Industrial Maintenance Coating Designed for TPO and PVC Roofing Systems

EverprimeEverest Systems offers Everprime All Ply, a primer for various new and aged single-ply membranes. According to the manufacturer, this high-quality, plasticizer free, single component, solvent based primer can be applied by a spray brush or a roller. The product is designed to provide exceptional adhesion to new and aged TPO and PVC membranes. In addition, this high-performance coating provides excellent surface for subsequent application of acrylic, 100 percent solids Silicone and fluoropolymer coatings.

For more information, visit http://everestsystemsco.com.

Rooftop Decks Add Outdoor Living Space to Sacramento Town Homes

The three-story homes are built on narrow lots without a backyard, so the decision was made to offer a roof deck package to provide an area to enjoy the outdoors. Photo: The Grupe Company

More and more, builders, architects and designers are looking to the rooftop as an area for usable living space — especially in urban areas, where lots are narrow. For a new town home development in Sacramento, the idea to add rooftop decks emerged late in the design process, but it’s proved so popular the builders are not only glad they made the change — they are considering making it a standard feature in future projects.

Designed by Ellis Architects and built by The Grupe Company, the neighborhood is known as 20 PQR. “The project fronts on 20th street in mid-town Sacramento and runs from P Street down to R Street,” notes Ron Rugani, vice president and purchasing manager for Grupe. “Q Street runs down the middle of the project, so that’s how we came up with the name 20 PQR.”

The 32 town homes are arranged in four groups of eight. The three-story residences have two different floor plans, one with 1,750 square feet and the other 1,850 square feet. “It’s an interesting concept,” Rugani says. “They are really considered single-family homes. They have their own lot, and they are detached from the next unit. There is a 6-inch space between the units, and they don’t share a common wall. However, the way we trim out that space, on the top and sides, you would view the eight units as one building, but they are actually eight individual single-family detached town homes.”

The narrow lots left no room for a yard, so that’s what inspired the idea to create usable outdoor space on the roof. “If you can imagine the urban setting — the fronts of these units are right on the city sidewalk. All of the units have two-car garages in the back and are accessible through a common alley. But there is no outdoor living space, and so that’s essentially what’s driving these roof decks,” Rugani says. “The backyard is where people are going to have outdoor living in a typical single-family home, and the rooftop deck is where they are going to have outdoor living in a town-home setting.”

The low-slope roofs were designed with internal drains and parapet walls. A GAF TPO roof system was specified. When the decision was made to add the rooftop living area, Ellis Architects recommended installing rubber roof deck tiles from sofSURFACES on top of the TPO roof. “The architect steered us in this direction because they liked the product,” notes Rugani. “After the roofer installs his regular TPO roof, it gets inspected to make sure there are no leaks before the roof deck tiles are installed. It’s a really unique product. It allows water to go through to the TPO roof for drainage. It has an excellent warranty, and so we have a long-term warranty for the entire roof system.”

Applying the Roof System

The TPO roof system was installed by PetersenDean Roofing and Solar, Fremont, California. “We are a roofing subcontractor for Grupe on several projects in the Northern California area,” says Mark Vogel, president of PetersenDean’s Builder Division. “We have built a great relationship with them over the years.”

Photo: sofSURFACES

There was approximately 900 square feet of roof area on each structure. PetersenDean crews mechanically attached the 60-mil GAF EverGuard TPO membrane over quarter-inch Georgia-Pacific DensDeck roof board and rigid insulation. “It is a flat roof with low slope conditions,” Vogel says. “This is absolutely a great system for this type of work.”

The parapet walls greatly simplified the safety plan, but safety is never taken for granted, according to Vogel. “We have 22 safety engineers nationwide, with 14 in California,” he says. “Safety is our biggest concern, and we invest to ensure we send everyone home at night. Our workers are considered our most valuable asset and we strive to maintain a world-class safety culture. Having a skilled and talented workforce that truly cares about safety drives everything that we do.”

Everything on the project went smoothly, notes Vogel. “It was not tough to coordinate the work with the other trades,” he says “It is what we do, and there is no one better. We are a full-service roofing contractor and solar power installer. We handle estimating, design, permitting, and installation for roofing and solar roofing systems for all our clients and this project is a great example of this.”

Installing the Roof Tiles

The deck area on each roof encompassed approximately 700 square feet. The interlocking duraSTRONG tiles are made from recycled rubber and are ideal for outdoor rooftops, walkways and patio projects, notes Chris Chartrand, director of marketing for sofSURFACES. “This space was ideal for our product as the rooftops are flat and have proper slope with a contained edge,” Chartrand says. “The design allows for efficient drainage of surface water.”

The low-slope roofs were covered with a TPO roof system manufactured by GAF, and the deck areas were topped with interlocking rubber paving tiles from sofSURFACES. Photo: sofSURFACES

The tiles were applied by a manufacturer-certified installer, Leonard’s Construction of Fontana, California. “Coordinating delivery and installation of our product within Grupe’s required timelines was a fairly easy task, as we were the last phase of the project,” notes Chartrand.

Paulo Carrillo, installation supervisor, typically installs the product in gyms and playground areas, but recently he’s found himself doing a lot of work on terraces and rooftops. After the roof system was completed on the homes at 20 PQR, a second sheet of TPO membrane was installed as a protective barrier. “We chalked our lines on that,” Carrillo notes. “We measure out the whole rooftop and chalk it off into a 2-foot-by-2-foot grid. Every other square is a keystone — those are the tiles that we put in first that hold everything in line.”

After the keystones are glued in place, the crews cut pieces to fit along the perimeter and then begin to add tiles in strategic lines. After those tiles cure, tiles are laid in opposite directions, both horizontally and diagonally. “We do it step by step,” Carrillo notes. “When we put the final squares in at the end, they are all interlocked together. After we do the final step, we glue each seam, so everything is 100 percent glued.”

The tiles all interlock, and compression allows for expansion and contraction. “Every tile is 24-1/8 inches, but they go into a 24-inch space,” Carrillo explains. “They are all compressed. With any perimeter cuts, we add another 1/8 of an inch to get our compression.”

Stacking the Deck

According to Rugani, Phase 1 and Phase 2 of the 20 PQR have been completed and are sold out, while Phase 3 and Phase 4 are currently under construction.

The interlocking duraSTRONG tiles are made from recycled rubber. They are designed for use on rooftops, walkways and patio projects, as well as gyms and playground areas. Photo: sofSURFACES

Originally the roof deck area was offered as an option, but it’s proved so desirable all of the units in the last phase are being built with decks. “It’s been an interesting dynamic,” says Rugani. “When we started, we weren’t sure how many people would want this option. For the first phase, we had to spec those, so, we said, let’s build six of the eight with the roof deck. It started to gain in popularity, and the price didn’t seem to be an issue, so in the last phase, we said, let’s build them all. It’s become very popular.”

Based on the success of the roof decks at 20 PQR, Grupe is exploring roof deck options for other projects in development. “We are building a mid-rise apartment complex just a few blocks away, and we said from the get-go in that project that we are going to have some type of roof deck for outdoor living space for the tenants,” Rugani says. “For that project we did develop a rooftop deck, and I believe that is going to be the M.O. moving forward in any project we do. Otherwise there might be no place for tenants to gather on site and have some outdoor living space. It makes perfect sense to go to the roof. So, yes, I see this as a trend, especially in urban settings.”

In the 20 PQR project, the homes were not originally designed with roof decks, and the decision made to add them later meant a lot of extra time and work for engineers and architects. “A lot of people might walk away from that and say it is too much work,” Rugani says. “We said, this is something we need to do, and it’s going to benefit the people who buy it. We were happy in the end that we spent the time and effort to do it.”

TEAM

Architect: Ellis Architects, Sacramento, California, www.ellis-architects.com
General Contractor: The Grupe Company, Stockton, California, www.grupe.com
Roof System Installer: PetersenDean Inc., Fremont, California, www.petersendean.com
Rubber Paving Tile Installer: Leonard’s Construction, Fontana, California

MATERIALS

Rubber Paving Tiles: duraSTRONG, sofSURFACES, Petrolia, Ontario, Canada, www.sofsurfaces.com
Roof Membrane: 60-mil TPO, GAF, www.GAF.com
Cover Board: DensDeck, Georgia-Pacific, www.densdeck.com

Easy-to-Use Discs Enable Induction Welding of PVC and TPO Membranes Over EPS Insulations

With induction welding, the membrane is heat bonded to the top of each plate and there are no penetrations in the membrane. Photo OMG

Over the past ten years, North American roofers have begun to adopt induction welding as a fast, simple and secure way to mechanically attach TPO and PVC membranes. The method also helps create a high-performance roof assembly by eliminating fastener penetrations of the membrane.

For most of its history, induction welding was limited to installations over thermoset insulations such as polyiso or over other rigid insulations with a cover board. But now, a deceptively simple and easy-to-use disc enables roofers to use induction welding over expanded polystyrene (EPS) insulations that don’t have cover boards. The result is faster and more affordable insulation installation and lower fatigue for work crews.

The Induction Welding Method in Brief

A roof fastener manufacturer pioneered induction welding attachment as a way for roofers to streamline TPO and PVC membrane installation, while avoiding membrane penetrations, for a more watertight roof assembly.

A roofing technician seals the seam with hot-air welder. Photo: Insulfoam

In a typical mechanically fastened membrane system, roofers secure the membrane with 2-inch to 3-inch diameter plates on the seams held down by screws that pass through the membrane and insulation layers to the underlying deck. With the induction welding method, each plate becomes a fastening point for the membrane, and the membrane is heat bonded to the top of each plate. With this method, crews screw down the insulation layer as usual, then unroll the membrane over the insulation. They then place a stand-up or handheld induction welding tool on the membrane at each plate location. In less than five seconds, the tool heats the plate under the membrane to about 400 degrees Fahrenheit, bonding the membrane to the plate. Heating is accomplished via electromagnetic induction between the tool and the plate, rather than via direct application of heat (think of an induction cooktop compared to conventional stove heating coils). Induction welding meets the FM 4470 approval standard and is accepted by most membrane manufacturers.

Induction welding typically requires 25 percent to 50 percent fewer fasteners and plates than typical mechanically fastened installations, as well as fewer seams, resulting in both labor and material savings. As the fasteners are spread across the roof in a grid pattern, the resulting assembly enhances resistance to wind uplift and reduces membrane sheet flutter.

EPS Insulations and Induction Welding

Until now, the induction welding process could not be used with EPS insulations that lacked a cover board, as

EPS insulations can be used in both new construction and roof recovers. Photo: Insulfoam

the 400-degree heated plates caused the insulation to soften and draw back. This resulted in numerous depressions in the roof assembly (at each fastener location), where water could pond.

To enable use of the induction welding process with a broader range of rigid foam insulations, fastener manufacturers have developed a simple solution. For each fastener, crews place a thin disc between the fastener plate and insulation. This separation medium protects the EPS from the high heat of the induction welding process, without interfering with the bond between the membrane and the fastener plate. Manufacturers typically refer to these separators as “induction welding cardboard discs.” While they are paper-based products, calling them “cardboard” understates their performance, as they are densely compressed and have a moisture-resistant coating, so they work well in high-performance roof systems.

Why This Matters

For roofers who prefer using EPS insulations for the products’ thermal performance and ease of installation, the discs allow them also to achieve the benefits of the induction welding process discussed above.

Induction welding cardboard discs enable use of the induction welding attachment process for TPO and PVC membranes over EPS insulation. Photo: Insulfoam

While induction welding has always been possible using EPS insulation products that have standard cover boards, the discs make it possible to induction weld over EPS products with glass facers and fanfold EPS with polymeric facers. Glass-faced EPS products can be used in new applications and recovers while roofers typically use fanfold EPS in roof recovers.

Fanfold EPS bundles, like R-TECH FF and others, are available in standard sizes up to 200 square feet, comprised of 25 panels that are 2 feet by 4 feet each, and come in various thicknesses. A typical two-square bundle weighs less than 11 pounds, so it is easy for one person to carry. EPS fanfold bundles require fewer fasteners per square foot than most roofing insulations and are less expensive than virtually every recover board. The man-hours needed to install fanfold bundles are about 60 percent less than working with individual sheets. Material costs are also lower than wood fiber, perlite, or gypsum board. On large projects, the

Induction welding typically requires fewer fasteners and plates than mechanically fastened applications, resulting in both labor and material savings. Photo: OMG

total savings can add up to tens of thousands of dollars. As with other EPS insulations, the product’s light weight also means less crew fatigue.

As roofers look for ways to create cost-effective, high-quality roof assemblies, new methods provide the opportunity to boost the bottom line by reducing labor and material costs. A simple, affordable disc now enables you to obtain the benefits of both the induction welding method for fastening TPO and PVC membranes and the advantages of EPS insulations.

Hospital Pedestrian Overpass Poses Logistical and Safety Challenges

The elevated pedestrian walkway at the BJC Healthcare/Washington University Medical Center complex connects the parking garages to buildings in the medical campus. It is approximately 1,200 feet long. Photo Paric Corporation and KAI Design & Build.

“The more complicated and complex the project, the more it is up our alley,” says Drew Bade, project manager for Bade Roofing Company in St. Louis, Missouri.

The company’s recent work roofing the new 1,200-foot-long elevated pedestrian walkway at the BJC Healthcare/Washington University Medical Center complex in St. Louis certainly qualifies as complex. The fully enclosed walkway connects the parking garages to buildings in the medical campus. Constructed atop 14 concrete pillars at an elevation of approximately 40 feet over busy roadways, the 13-foot-wide structure posed obvious logistical and safety challenges.

Bade Roofing’s union-affiliated workforce focuses on commercial projects, and the lion’s share of the company’s work is in the re-roofing arena. But for this new construction project, designed and executed through a joint venture between KAI Design & Build and Paric Corporation as part of a long-term project to update the medical campus, Drew Bade knew his company was the right candidate for the roofing portion of the job. The successful roofing installation proved him right. “We teamed up with Paric and KAI and made this thing happen,” says Bade.

The Roof System

The heated and air-conditioned walkway features carpeting, LED lighting, security intercoms, windows and metal wall panels. It also features a durable roof system. “It’s a walkway, but this thing was built like a tank,” notes Bade.

The walkway was constructed atop 14 concrete piers that elevate it over busy roadways. Photo Paric Corporation and KAI Design & Build.

The roof is a Firestone TPO system that includes R-20 polyiso insulation and a half-inch DensDeck cover board from Georgia-Pacific. The 60-mil UltraPly TPO membrane was attached using Firestone’s InvisiWeld induction welding system. The base of the system is the walkway’s 18-gauge steel deck, which features interior drains, scuppers and downspouts. Tapered insulation was used to provide proper drainage.

To make the project’s logistics even more complicated, work was scheduled on the fly as different areas of the walkway were completed. “There were some areas that weren’t built yet when we started to put this roof on,” Bade recalls. “It was a fluid situation. It was a challenge just to keep up with the changes, and we had to bounce around a lot. We couldn’t just start at one end and roof our way over to the other end. We had to hop around and handle what was finished at the time, tying the sections in together as they were completed.”

The short parapet walls were capped with edge metal after the roof was installed. “In some spots, after the roof was put on, it was more like a drip edge than a parapet,” Bade says. “At the highest, it was about 8 inches. We installed edge metal that tied into the metal wall panels they used on the sides of the bridge. It was all integrated together.”

Loading components proved tricky. “Getting material to each section and moving it around was a challenge in itself,” Bade explains. “We had to coordinate certain time frames that we could get our crane into an area to drop the material off. Because of how the safety systems were set up and how narrow this bridge was, you couldn’t really transport material along it very far. The crane essentially had to put the material right where it was going to go for that day.”

Loading the roof was usually done first thing in the morning, as use of the crane could mean blocking off roads or going into gated areas. “We’d try to beat all of the other trades in there,” Bade says.

The Safety Plan

The key to executing the project was finding the right safety plan. Initially the team explored the use of a

The Beamguard lifeline system from Guardian Fall Protection was installed in the center of the roof deck by workers in a boom lift. Photo Bade Roofing Company.

temporary guardrail system, but it proved infeasible due to the short parapet walls. “We use temporary guardrails on almost 100 percent of our projects, but the engineer came back and said the parapet walls weren’t strong enough to support a guardrail system,” Bade recalls.

The company looked for other options. “We looked at a special system that is more commonly used on road bridges during construction,” he says. “It uses a cable that runs between stanchions, and crew members can clip off to the cable.”

The system chosen was the Beamguard lifeline stanchion system from Guardian Fall Protection. The posts were attached to the steel I-beams every 30 feet. “We had to cut the metal deck out and clamp the posts to the I-beams,” Bade explains.

Crew members’ personal fall arrest systems were connected to the lifeline, but only two workers could tie off to the cable in between the stanchions. “We were tied off 100 percent of the time,” Bade says. “Safety was a huge issue for everyone on this project. There were no warnings. Everyone knew that if someone wasn’t tied off, they’d immediately be thrown off the job.”

The stanchions for the lifeline system were attached to the steel I-beams under the roof deck. Photo Bade Roofing Company.

The cable system posed some limitations on crew movement, which affected the delivery of materials. “With the cable system, you could only go so far because only two people could be tied off to a 30-foot section at a time. Essentially you had two guys walking 30 feet to hand insulation boards to the next two guys. It was kind of like a chain gang, moving material down each section of the roof.”

Ensuring the safety of pedestrians and vehicles below was also crucial. “There was a sidewalk area in the parking garage that was fully functional during the project, as there was a walkway constructed of scaffolding that offered overhead protection,” Bade notes.

However, other areas of sidewalk and roads had to be closed in order to complete work on some sections. “It depended where you were working that day,” Bade says. “Some areas of sidewalk had to be closed, and sometimes we had to redirect traffic. If you were working in areas without scaffolding, you would have to have two guys on the ground with flag lines directing traffic and blocking people off.”

One crucial section over a busy road posed some additional challenges. The three-lane road could only be shut down on one weekend. All of the trades had to complete their work that weekend, so the roofing installation had to be completed in just one day. “We did a 120-foot stretch of the roof that crossed this main road, and we did it all on a Saturday. It was the only opportunity we had. Otherwise we would’ve had to pay to shut the road down lane-by-lane, as we went. We were lucky that we were able to get in there on that one day and finish the whole length.”

The roofing installation was completed in sections as they were constructed after the 18-gauge steel deck was in place. Photo Bade Roofing Company.

Communication between all of the companies involved in the project was essential, notes Bade. “The foremen for every trade met every morning before work started. All of the contractors on the project had their meeting every week to plan and go over everything,” he says. “There were multiple forms you had to fill out every morning. The paperwork on this project was flying like you wouldn’t believe.”

After the work was completed in each section, the safety system had to be disassembled and removed. The last chore completed on each portion of the roof was to fill in the patches of roofing material where the stanchions had been. Workers completed these last steps tied off to a snorkel lift.

Despite the logistical hurdles, the project went smoothly and feedback has been positive, notes Bade. “It ended up being a great project for us,” he says. “It turned out really nice.”

It’s just another tough project now in the rear-view mirror. “The coordination, the safety, and the complexity of the actual roof system itself — not that it was necessarily a difficult roof to install, but given where it was, and how difficult it was to access — it all shows how dedicated and skilled our company is,” Bade concludes. “I don’t think there are a lot of companies out there that could do this project.”

TEAM

Architect: KAI Design & Build, St. Louis, www.kai-db.com
General Contractor: Joint venture between KAI Design & Build and Paric Corporation, St. Louis, www.paric.com
Roofing Contractor: Bade Roofing Company, St. Louis, www.baderoofing.com

MATERIALS

Membrane: 60-mil UltraPly TPO, Firestone Building Products, www.firestonebpco.com
Cover Board: DensDeck, Georgia-Pacific, www.densdeck.com

Adhesive-Free Roofing System Eliminates Temperature Restrictions

Carlisle SynTec Systems introduces its RapidLock (RL) Roofing System. This adhesive-free system uses VELCRO Brand Securable Solutions to fully attach 115-mil FleeceBACK RL EPDM or FleeceBACK RL TPO to InsulBase RL or SecurShield HD RL polyiso insulation. According to the manufacturer, the RapidLock system does away with temperature restrictions, has no VOCs or odors, offers wind uplift ratings comparable to traditional fully adhered single-ply systems and has a Factory Mutual 1-90 approval rating. The adhesive-free system also saves time and labor.

Carlisle’s new RapidLock Roofing System was unveiled at the 2018 International Roofing Expo in February 2018, where it won Best Commercial Product in the Expo’s Product Showcase. Judges reviewed new products and selected winners based on a number of criteria including innovation, productivity, and cost-effectiveness.

“We’re very excited about this product, seeing that it’s an industry first – a fully adhered system that’s adhesive-less,” said Chad Buhrman, Carlisle’s Insulation Product Manager.

“Carlisle’s RapidLock system is a game-changer for contractors. RapidLock installations are quick, quiet, and odor-free, making this system an ideal solution for occupied buildings,” said Austin Kulp, Carlisle’s FleeceBACK Product Manager.

For more information, visit www.carlislesyntec.com.

Silicone Coating Restores the Roof, Reduces Utility Costs at Mixed-Use Complex

At the Shoppes of Johnson’s Landing in Angier, North Carolina, ACC applied a high-solids silicone roof coating on the 20-year-old metal roof to seal penetrations, restore the roof, and provide a white reflective coating. Photos: All-County Contracting (ACC)

Glenn Wujcik, the owner of All-County Contracting (ACC), headquartered in Raleigh, North Carolina, has been fascinated with spray rigs since he and his brother first used one in 1979 to insulate a van with spray polyurethane foam (SPF). His company specializes in applying SPF and roof coatings on existing buildings. Lately, he’s found silicone roof coatings are making up an increasing share of his company’s workload.

“The coatings industry in general is booming right now,” Wujcik says. “A lot of the TPO and EPDM roofs are nearing the end of their service life, and instead of tearing them off, if you catch them in time, you can go over it with the silicone coating and get a new 10-year warranty. Silicones have a proven track record. When you put it on properly, it weathers really well. It has excellent elongation.”

Wujcik characterizes himself as a hands-on owner who strives to be on the site for every job. He believes there is an art as well as a science to operating a spray rig properly, and experience is crucial. “I love doing this,” he says. “I’ve been doing it for more than 30 years, my business partner’s been doing it more than 30 years, and our best sprayer has sprayed more than both of us combined. We know what we have to do, we know how long it’s going to take, and we have the right equipment. We are really good about the preparation and the application.”

Coatings and spray foam are excellent products, but only in the right situations, notes Wujcik. They should only be used on the proper substrates and applied in the right conditions. “In spraying, the most important thing is knowing when not to spray,” he says. “Right now, I’m working on a job, and for the last two days, there have been 10-20 mph winds, and I haven’t finished it yet. I told the owner, ‘I haven’t oversprayed anything yet, and I don’t want to.’ I’d rather do it right and not have any problems.”

Wujcik points to a recent project on a mixed-use building in Angier, North Carolina, to illustrate some of the benefits of a silicone roof coating. “It’s a U-shaped building with about 14,000 square feet of roof space,” Wujcik notes. “There’s a bakery, a restaurant, a pharmacy, and a doctor’s office, and there are a lot of penetrations on the roof.”

The penetrations were the site of multiple leaks. Wujcik decided to use a high-solids silicone coating, GE Enduris 3502, to prevent leaks and extend the life of the roof. The monolithic coating will seal the penetrations, and the white reflective surface will provide an additional benefit: reduced cooling bills in the summer. “Putting a white coating on it is going to reduce their energy load in the summer pretty substantially,” he says.

Applying the Coating

On this project, the first step was to pressure wash the existing roof. “That’s where most coating jobs fail — surface preparation,” Wujcik states. “Washing the roof properly is one of the most important steps.”

The high-solids silicone coating was applied to the existing standing seam metal roof. Care had to be taken to ensure all sides of the metal ribs were properly covered with the material. Photos: All-County Contracting (ACC)

The company uses 4,000 psi belt-drive power washers, so care has to be taken not to damage the roof or skylights, which are covered and marked for safety reasons. The company follows all OSHA regulations, which in most cases means setting up safety lines 6 feet from the edge, with stanchions 10 feet apart, to establish a safety perimeter.

“Safety is my number one thing,” Wujcik says, “I’ve been doing this a long time and I’ve never had a lost-time accident. I preach safety. That is absolutely the most important — and accidents are expensive.”

The next step is to apply the GE Seam Sealer at the penetrations. “When this roof was originally installed 20 years ago, they did it textbook perfect,” Wujcik notes. “Each 4-inch pipe coming though had at least 20 fasteners holding it down.”

However, over time, the rubber grommets on the fasteners can degrade, and expansion and contraction can take their toll. “We have really hot summers here, we’ve seen roofs where literally thousands of fasteners have backed out,” he says.

The seam sealer is typically applied with a brush. “Any horizontal seams, any termination bars, any penetration that goes through the roof that has a screw, we apply the seam sealer,” he says. “It goes on quite thick — at about 80 linear feet per gallon.”

After the seam sealer cures for one day, the coating is applied. Spraying flat roofs with EPDM, TPO, and PVC membranes is a fairly straightforward process, according to Wujcik. “You basically spray it just like you would spray paint a wall,” he says. “You overlap your spray pattern 50 percent. I’ve been doing it for so many years, and you get a feeling for how fast you can go.”

After the roof was power washed, the seam sealer as applied to the seams and penetrations. After it cured, two coats of the high-solids silicone product were sprayed on the roof. Photos: All-County Contracting (ACC)

A wet mil gauge is used to ensure the proper thickness. Wujcik notes the high-solids silicone formulation has very little shrinkage as it dries.  “As we’re spraying, we insert the gauge into the wet coating and it tells you how many mils you have sprayed down. In this case, we were applying to achieve 21 dry mils.”

The spray rig is set up on the ground and operated by one man, while the sprayer and the hose man are working on the roof. “It’s a minimum of a three-man crew per coating rig,” he notes. “You’re dealing with about 6,000-7,000 psi of pressure, so you need special hoses rated for at least 7,000 psi. You never want to kink them. If you busted a hose, by the time someone came down from the roof to the machine, you could pump out 20 gallons on the ground. That’s why you need a ground man.”

Flat roofs are sprayed perpendicular to the roof, but the standing seam metal roof on this project called for a different technique. “On metal roofs with high ridges, if you don’t angle your gun you’ll miss the sides of the ribs,” Wujcik points out. “You have to do it from one direction, working one way, and then turn around and do it from the other direction, working the other way. If you try to spray straight down on the roof, you’re going to miss the nooks and crannies in all of those ribs.”

The surface area of the ribs also has to be taken into account when calculating the amount of liquid that will be applied, notes Wujcik.

The final step in the process is to touch up the applications at the penetrations to ensure a clean look. On vertical surfaces including parapet walls, crews ensure the coating is applied to a uniform height. “On the last day, we take up brushes and rollers and cut in straight lines,” he says. “That really finishes the job. The detailing gives it that final touch.”

Open for Business

The active and open jobsite posed some challenges. “There were a lot of cars around the building, so we had to be very careful not to hit them with overspray,” Wujcik notes. “When you’re working on a plant, you might be able to move all of the cars to a different location, but at doctor’s offices and restaurants, you have traffic in and out of the parking lot all of the time. We can use car covers if there are a few cars there, but when they are in and out like that, it’s not practical, so you have to be very careful when you do the job.”

The job was completed in the winter, and bad weather resulted in some delays. “A job like this in the summertime would have been a weeklong project at most,” Wujcik notes. “This project took almost a month because we had an exceptionally cold winter with a lot of high winds. It took extra time, but that’s my philosophy: If it’s not the right conditions, I just won’t do it.”

The project qualified for a 10-year warranty, and when it expires ACC plans to be there to pressure wash and recoat the roof for another 10-year warranty.

“We inspect our jobs every year,” Wujcik says. He notes that annual roof inspections and routine maintenance are the simplest and most cost-effective ways to ensure the roof’s life span. Yet these steps are often neglected.

“It’s amazing that some of these multi-million-dollar companies don’t send their maintenance guys up on the roof for 10 minutes to check the drains,” he says. “If a roof has 2 inches of pine needles around the drain, the whole roof has to have 2 inches of water on it before it begins to drain. That puts tremendous, tremendous stress on a roof. Keeping your drains clear is really important.”

TEAM

Roofing Contractor: All-County Contracting (ACC), Raleigh, North Carolina

MATERIALS

Roof Coating: Enduris by GE 3502, GE Performance Coatings, www.GE.com/silicones
Seam Sealer: GE Seam Sealer, GE Performance Coatings

Multifaceted Residential Project Puts Contractor to the Test

Photos: Petersen

Diversification has always been a key component of Paul Graham’s business philosophy. Graham is the president of StazOn Roofing Inc., headquartered in Dallas, Texas. The company has been in business 38 years, handling all types of roofing, custom sheet metal fabrication and specialty wall panel systems.

Graham designed his company to be able to tackle multiple scopes of work on complicated projects. “Through time and through practice on all of these jobs, we’ve just been able to step up to the plate and maintain a multi-level task force to handle different types of work on the job,” he says.

The company’s diverse portfolio has been on display at Craig Ranch, a multi-phase residential development in McKinney, Texas. “It’s a high-end multi-family project,” Graham notes. “The most recent phase of the project involved a few five-story and predominately four-story buildings, all wood-framed. There are pools and courtyards with amenity areas for the residents.”

The buildings featured a blend of different roof systems. Crews from StazOn installed 60,000 square feet of shingles on roofs with a 4:12 pitch, 52,000 square feet of TPO on low-slope areas, and 8,500 square feet of standing seam metal roofing on roofs with an 8:12 pitch. They installed 22,000 square feet of standing seam wall panel cladding. The metal roof and wall panels were custom fabricated by StazOn with PAC-CLAD metal from Petersen in two colors, Zinc and Weathered Steel.

The company also fabricated and installed trim, flashing, gutters, collector boxes and rectangular downspouts. “We have our own sheet metal shop, so we can manufacture any type of architectural sheet metal product for our own jobs,” Graham says. “We also provided the builder with a proprietary door pocket at each of the door locations.”

Up on the Roof

The roofing work came first. On the large multi-family buildings, GAF EverGuard 60-mil white TPO was applied on the low-slope sections, which house the mechanical units and serve as a design feature on the project. “These were on the

Craig Ranch is a multi-phase residential community in McKinney, Texas. Condominiums and town homes feature shingles and standing seam metal roofs. The metal wall panels are a distinctive focus of the design. Photos: Petersen

perimeter of the buildings, primarily,” Graham explains. “The architect likes to showcase the walls, so to create that effect, they design a flat roof adjoining the pitched roof sections.”

GAF Timberline Dimensional Shingles in Weathered Wood were installed on the steeper sections of the large multi-family buildings. “These roofs had long, big runs,” Graham notes. “It was kind of like a roofer’s dream if you will, to shingle up there with nothing in the way. It was pretty wide open.”

Metal roofs were installed on a section of town homes. Where the intersecting roof sections formed valleys, crickets were installed to provide adequate drainage. These cricket sections were covered with TPO, and the details where the TPO roof and metal roof came together were crucial. “We terminated the TPO at the sloped roof with a receiver flashing that we heat welded to the TPO,” says Graham. “We take it one step further with that application, so we have a complete watertight transition from the TPO to the bottom of where the metal panel starts.”

The crickets divert water to the exterior, where it drains through the custom-made collector boxes. “The downspouts in those locations are oversized four-by-six downspouts fabricated at our shop from the Petersen material,” Graham notes. “Along with the other sheet metal items, we did the coping, the pre-flashing and flashing, the edge trim, and miscellaneous other vertical and horizontal expansion details.”

On the Walls

After waterproofing inspection of the exterior facade was completed, crews first applied a peel-and-stick building wrap from Grace, Vycor enV-S. “We took field measurements and we custom made all of the trim out of the four-by-eight sheets that Petersen supplied for the job,” Graham explains. “We make all of the trim to fit the windows, doors, penetrations, the steel support beams, which all get pre-flashed and clad.”

The metal roof and wall panels were custom fabricated with 24-gauge aluminum supplied by Petersen. Photos: Petersen

The 16-inch-wide wall panels were fabricated on the site. “We keep the panels protected until the guys are ready to install them,” Graham says. “We have everything we need right there on hand so we can keep up with the needs of the job as it is evolving.”

Panels are installed using a man lift. “From a safety standpoint and a production standpoint, it made sense to use the man lifts,” says Graham. “It’s the most maneuverable way to do the installation. We work in synchronization, moving three or four lifts at a time along the side of these walls as we work our way around the project.”

One unexpected challenge was a section of the leasing office that did not line up perfectly. “The builder came to us and asked if we could build the wall out and make sure all of the wall panels on the facade would be flush once the building was completed,” notes Graham. “We made some custom 16-gauge steel hat channels and Z-members and installed them as structural members to the wall. Then we installed the panels over the steel framing, so that we would have that same elevation and same build-out across the front of the building.”

Coordinated Attack

Phase III of the project was just completed, and Phase IV is now underway. Graham points to a few keys to navigating complicated projects like these. “It usually is a tight schedule, so coordinating with the builder to keep everything on schedule is the key,” says Graham. “You have to fabricate the necessary components and deliver them to the job in a timely fashion to keep the crews on target.”

Crews from StazOn Roofing installed the roof systems and wall panels, as well as custom-made trim, flashing, gutters, and downspouts. Photos: Petersen

Maintaining the consistency and quality of the details is also important, and experience helps. “We know what works best for the long haul,” he says. “At the end of the day, you want those details to line up with what the architect had as his vision, but we will make recommendations if we think there is a better way to construct a detail for specific conditions.”

The wall panels on this project were a top priority. “The specialty wall panel systems are so architecturally significant,” he says. “We kind of live and breathe them. We understand them. We’ve come across many, many challenges along the way on other jobs, so when we run into a new challenge, we just roll up our sleeves, get it figured out, design it with all of the people involved, and get going with it.”

Graham credits the Dallas-based builder and the Dallas-based architecture firm, JHP, for spearheading the successful project. “It’s nice when you have a team you’ve worked with and everyone understands what needs to be done to satisfy the client’s desires,” he says.

TEAM

Architect: JHP, Dallas, Texas, www.jhparch.com
Roofing Contractor: StazOn Roofing Inc., Dallas, Texas, www.stazonroof.com

MATERIALS

TPO: EverGuard 60-mil white TPO, GAF, www.GAF.com
Asphalt Laminate Shingles: Timberline Dimensional Shingle in Weathered Wood, GAF
Metal Roof and Wall Panels: PAC-CLAD 24-gauge aluminum in Zinc and Weathered Steel, Petersen, www.Pac-Clad.com
Building Wrap: Vycor enV-S, Grace, www.gcpat.com

Building to Last With Asphalt-Based Roofing

The property owner of this building opted for a BUR/modified-bitumen hybrid system with reflective white coating. Photos: Johns Manville

The advantages of a built-up roofing (BUR), modified bitumen, or hybrid roofing assembly include long life, a variety of maintenance options, and outstanding puncture resistance. This durability means property owners will spend less time worrying about fixing leaking roofs and the associated hassles — lost productivity, disruption in operations, slips and falls, repair bills, and other liabilities.

Recommending clients install a roof system that gives them the best chance of eliminating unproductive distractions is a good business decision for design/construction professionals. A more durable roof will enable property owners to focus on making profits instead of dealing with the aftermath of a roof leak.

“I have no problem endorsing asphalt-based roofing,” says Luther Mock, RRC, FRCI and founder of building envelope consultants Foursquare Solutions Inc. “The redundancy created by multiple plies of roofing is really what sets systems like BUR and modified bitumen apart.”

One can argue BUR’s closest cousin — the modified bitumen (mod bit) assembly — is actually a built-up roof made on a manufacturing line. The reality is the plies of a BUR create a redundancy that can help mitigate any potential oversights in rooftop workmanship.

BUR systems are offered in a variety of attractive and reflective options with a proven track record of performance. Photos: Johns Manville

“I’ve replaced BURs for clients I worked with 30 years ago,” says Mock. “We recently replaced [a BUR] specified in the early 1980s. And the only reason was because some of the tectum deck panels had fallen out of the assembly. Meanwhile, the roof was still performing well after 30 years.”

According to the Quality Commercial Asphalt Roofing Council of the Asphalt Roofing Manufacturers Association (ARMA), one of the main drivers of the demand for BUR systems is the desire of building owners for long life cycles for their roofs.

“A solid core of building owners and roofing professionals in North America continue to advocate asphalt-based roofing systems because of their long lives,” says Reed Hitchcock, ARMA’s executive director.

Benefits of Asphalt-Based Roofing

Over the years, asphalt-based roofing assemblies have earned a reputation for reliability with building owners, roofing consultants, architects, engineers, and commercial roofing contractors. The original price tag tends to be greater than other low-slope roofing options, but these assemblies offer competitive life-cycle costs. BUR enjoys a track record spanning more than 150 years; it provides a thick, durable roof covering and can be used in a broad range of building waterproofing applications.

An aerial view of a reflective roof membrane. Photos: Johns Manville

Available as part of fire-, wind-, and/or hail-rated systems, BUR and modified bitumen assemblies offer proven waterproofing capabilities, high tensile strength, long-term warranties, and a wide choice of top surfacings (including ‘cool’ options). Their components include the deck, vapor retarder, insulation, membrane, flashings, and surfacing material. The roofing membrane can be made up of a variety of components, including up to four high-strength roofing felts, modified bitumen membranes (hybrid systems) and standard or modified asphalt. Hot-applied asphalt typically serves as the waterproofing agent and adhesive for the system.

The roofing membrane is protected from the elements by a surfacing layer — either a cap sheet, gravel embedded in bitumen, or a coating material. Surfacings can also enhance the roofing system’s fire performance and reflectivity ratings.

Another surfacing option is gravel, commonly used in Canadian applications where the existing roof structure can handle the extra weight. There are also several smooth-surface coating options, the most popular of which are aluminum or clay emulsion products offering greater reflectivity than a smooth, black, non-gravel-surfaced roof. These reflective roof coating options are typically used in warmer regions when required by code. Reflective white roof coatings are also becoming more popular.

Cold-Process BUR

Cold application of BUR has provided an alternative to traditional hot-applied systems for more than 48 years. The term ‘cold-applied’ means the BUR roofing system is assembled using multiple plies of reinforcement applied with a liquid adhesive instead of hot asphalt. These cold adhesives are used between reinforced base/ply sheets to provide a weatherproof membrane.

The owner of this shopping mall chose BUR primarily due to its redundancy. Multiple plies of roofing can provide extra insurance against water intrusion. Photos: Johns Manville

In BUR cold-process roof systems, manufacturers typically require that only fully coated, non-porous felts (such as standard base sheets) are used as base and ply sheets. Generally, an aggregate surfacing or a coating is then applied over the completed membrane to provide surface protection and a fire rating for the roof system.

“In the re-roofing market, we’re definitely seeing more cold-applied systems being specified, particularly with modified bitumen,” says Mock. “It’s a natural alternative when a building may be occupied during the reroofing process and hot asphalt is not an option.”

Adhesives can be manually applied with a squeegee, brush, or spray application equipment. When numerous roof penetrations or rooftop access become issues, manual application of adhesives is usually the best option. Proper coverage rates are vital to a successful, long-term, cold-applied roof system. Both spray and manual application methods require the proper amount of adhesive material be installed. If too little adhesive is applied, there is a potential for an improper bond to be formed between the felts. If too much is applied, then the potential for longer setup times and membrane slippage is increased. Additionally, ambient temperatures must be 40 degrees Fahrenheit (5°C) and rising before installation. This limits, but does not preclude, use of cold-process BUR in much of the northern United States and Canada.

“I’m also comfortable specifying BUR, because I’m confident I will have a seasoned contractor on the job,” says Mock. “The commitment in terms of skilled labor and equipment is simply too great for these contractors to be first-timers.”

Flashings are another critical component of every roofing system, particularly in cold-weather applications. Four-ply BURs use modified bitumen flashings almost exclusively. These membranes are predominantly styrene butadiene styrene (SBS)-modified and offer greater elongation in frigid climates where it counts most — at the interface of the roof system with other building components.

Use of a modified-bitumen base ply is one way of handling general flashing requirements, although modified bitumen cap sheets are more common.

BUR Repair and Maintenance

Like all roof systems to some extent, the life expectancy of a BUR system depends on the property owner’s commitment to routine maintenance. All roof systems can benefit from an owner willing to undertake a proactive management plan. BUR installed over an insulation package lends itself well to non-destructive testing in the future (e.g., infrared) as a means to maximize service life.

“Asphalt roofing systems have the potential for a very long life, and preventive maintenance is the key to realizing that potential,” says Hitchcock.

Non-gravel BUR surfacing options include aggregate, a mineral surface cap sheet, or a smooth, surface-coated membrane. Photos: Johns Manville

The goal is for problem areas to be detected and fixed before they develop into leaks. Inspections can reveal potentially troublesome situations, such as a loss of gravel surfacing, which could lead to felt erosion or brittleness. Less commonly, punctures and cuts to the membrane can occur, so it is wise to remove sharp objects and debris from the roof. Clogged drains or poorly sealed flashings also present problems that are repaired easily. The effects of chemical exhausts on roofing materials should also be monitored.

Preventive maintenance actions can help catch problems before they damage larger areas of the roof system. Inspections should be performed not only on aging roofs, but also on newly-installed roofs to guard against errors in installation, design, or specifications.

BUR and modified bitumen also have a long history of proven performance in the northern United States and Canada, where snow and ice buildup are common. Perhaps more than any other roof membrane, the BUR system shrugs off minor abuse.

BUR has proven to be a low-maintenance roofing system, and it can also be effectively repaired when needed. This means property owners can usually get more life out of a BUR. The ability to enhance the performance of existing BUR membranes with coatings, mod bit cap sheets, or flood coats of asphalt explain the long service lives of these systems in demanding applications.

“Property owners rarely have to replace a four-ply BUR until it is absolutely, positively worn out,” says one roofing contractor who asked to remain anonymous. “Based on experience, these asphalt-based systems ‘hang in there’ longer than less-robust roof options.”

When BUR Is Not the Best Option

There is no roofing product solution that will fit every building specification, and that certainly holds true for BUR. Probably more than any other roofing system (except spray polyurethane foam), the built-up roofing application is more of a skill than a science. As alternative systems have been introduced into the market, the job of finding experienced BUR contractors has become more difficult. This is especially true for the hot mopping of multi-ply BUR systems.

BURs are labor intensive and their installed cost will fluctuate with crude oil prices. However, as oil prices have continued to fall, BUR manufacturers have enjoyed the lowest asphalt pricing since the 2008-09 recession. (The price of oil peaked at about $117 a barrel in September 2012 and is $50 a barrel at this writing.) Typically BUR manufacturers will pass on a portion of these savings to their customers.

BUR has always held up well in life-cycle cost analyses. However, if a roof is not expected to last 20 years or more, it usually does not make sense to specify a premium four-ply BUR.

On larger projects, gravel-surfaced BURs are typically not practical from a cost standpoint unless a source of gravel is available locally. Projects where roof access is difficult often present challenges when roofing kettles are used. And despite the preponderance of low-fuming asphalts and kettles, re-roofing occupied buildings is often unacceptable to neighbors and/or the property owner.

Built-up roofing systems have sufficient strength to resist normal expansion and contraction forces that are exerted on a roof; however, they typically have a low ability to accommodate excessive building or substrate movement. Rephrased, if the roof must be used to “hold the walls” together or if the use of “loose-laid insulation” has a benefit, then a traditional three- or four-ply built-up roofing system is not a good choice.

A built-up roof typically provides high tensile strength with low elongation. Guidelines about where expansion joints should be installed in the roofing system should not be ignored by the designer. These guidelines include installing expansion joints where the deck changes direction, approximately every 200 feet (61 meters), although many consider that this dimension can be expanded for single-ply roofing membranes; where there is a change in deck material; and, anywhere there is a structural expansion joint, etc. Based on these requirements, on some projects it simply isn’t practical to use a BUR.

BUR materials must be kept dry before and during installation to prevent blistering in the roof system. Proper storage is the key: Do not overstock the roof; use breathable tarps to cover material on the roof; store material on pallets to minimize the possibility of material sitting in water; and store rolls on-end to prevent crushing. In general, polymeric single-ply membranes like TPO (thermoplastic polyolefin) are less susceptible to storage issues.

Many roof consultants and product manufacturers clearly state that there should be no phased construction of a built-up roof. If phasing is required, then a BUR should not be specified. This is a clean and simple rule to understand; if the roof being constructed is a four-ply BUR, then only as much insulation should be installed as can be covered the same day with all four of the plies in the built-up roofing membrane. Phased construction of a built-up roof greatly increases the potential for blistering of the membrane and does not allow for the total number of plies to be installed in a shingled fashion. Phased application contains other perils, such as roofing over a small amount of overnight precipitation or dew that, even with the best of intentions, can cause harm.

As stated above, costlier modified bitumen materials should be specified for flashings and to strip in metal. Stripping in two plies of felt will most likely result in splitting at the joints in a gravel stop because the two-ply application cannot accommodate the movement in the edge metal. On new or existing buildings where significant expansion/contraction is expected, a TPO, PVC or EPDM roof membrane can save the property owners money and eliminate premature roof failure due to roof splitting.

Conclusion

Manufacturers across North America are making asphalt roofing systems like BUR better and more versatile for architects, builders, contractors, roofing consultants, and building owner/managers. Thanks especially to the addition of polymers that add stretch and strength, architects can now specify a commercial, low-slope roof as part of a multi-ply BUR system any way they want it — hot, cold, torch, or self-adhered (hybrid BUR) — to meet the individual low-slope roofing project’s needs.

Most importantly, asphalt-based roofing products offer exceptional life-cycle cost performance. They have proven to be reliable, easy to maintain, and are trusted to perform exceptionally well in extreme weather conditions.

Portable RhinoBond Hand Welder Designed for Use in Tight Spaces

OMG Roofing Products introduces the RhinoBond Hand Welder. Based on patented Sinch Technology, the portable RhinoBond Hand Welder is designed to help roofers weld RhinoBond Plates in tight spaces such as under raised rooftop equipment and on vertical surfaces. The ergonomically designed tool features a vibrating handle and an indicator light that lets roofers know when the tool is activated and when the weld cycle is complete. The base is recessed and features centering indicator lines to help users properly align the tool over installed RhinoBond Plates for optimum bonding and improved productivity.

The new tool weights just six pounds (2.7 kg), and operates on 110V and 220V power sources for global use. Each tool comes with three, eight-inch tall magnets, and a durable carrying case that protects the induction tool when not in use. Using a 12-gauge RhinoBond Power Cord (sold separately), the independent Hand Welder can be operated up to 100-feet (30 m) from the power source. A quick connect power cord pig-tail enables international users to quickly switch to the local plug configuration for global use (international pig-tails sold separately).

“Many roofers understand the tremendous productivity and performance benefits that RhinoBond offers,” said Web Shaffer, vice president of marketing for OMG. “In fact, some roofers have seen productivity rates increase by 30%. To enhance the systems’ overall productivity, we wanted to offer a solution that can be used everywhere on the roof, even in tight spaces. This new product makes that possible.”

The RhinoBond System is designed for use with TPO and PVC roofing membranes and approved by most roofing system manufacturers. The System uses advanced induction welding technology to bond roofing membranes directly to specially coated plates used to secure the insulation to the deck. The result is a roofing system with improved wind performance that requires fewer fasteners, plates, and seams, and zero penetrations of the new membrane. Since it was introduced in 1998, nearly 2.0 billion square feet (185 million square meters) of membrane has been installed with the RhinoBond System around the world.

For more information, visit OMGRoofing.com.

Single-Ply Roofing Best Practices: Doing Everything Right the First Time.

Figure 1: Designing resilient roof systems is the best of practices. When developing details, we find it very helpful to draft out the roof system (for each different system), noting materials and installation methods. Photos: Hutchinson Design Group

Single-ply membranes have risen from being the “new guy” in the market in the early ’80s to become the roof cover of choice for most architects, consultants and contractors. Material issues have for the most part been resolved, and like no other time in recent history, the industry is realizing a period of relative calm in that regard. Whether EPDM, TPO or PVC, the ease of installation, the cleanliness of the installation (versus the use of hot or cold bitumen), the speed at which they can be installed, and the material costs all blend to make these materials a viable option for watertight roofing covers. But with this market share comes issues and concerns, some of which are hurting owners, giving forensic consultants such as myself too much business, enriching attorneys, and costing contractors and, at times, designers dearly.

Following are some of my thoughts on various issues that, in my opinion, are adversely affecting single-ply membrane roof systems. Paying attention to these issues will bring about best practices in single-ply applications.

Specifying the Roof by Warranty

OMG, can architects do any less? Don’t get me started. The proliferation of “canned” Master Specs which call for a generic 10-year or 20-year warranty and then state to install the product per manufacturer’s guidelines is disheartening. Do

Figure 2: Coordinating with the mechanical engineer in the detailing of the pipe penetrations is critical. Here you can see all the components of the curb, penetrations, roofing and waterproofing are noted. We recommend that the same detail be on the mechanical sheets so that at least an 18-inch curb is known to all. Photos: Hutchinson Design Group

designers realize that manufacturers’ specifications are a market-driven minimum? When architects leave out key details, they are simply relying on the roofing contractor to do what is right. This deserves another OMG. The minimum requirements for a warranty can be very low, and the exclusions on a warranty quite extensive. Additionally, a design that calls for products to be installed based on achieving a warranty may result in a roof system that does not meet the code. Owners are often oblivious to the warranty requirements, and all too often fail to ensure the standard of care until the service life is shortened or there is storm damage — sometimes damage the roof should have withstood if it were properly designed and detailed.

If one is not knowledgeable about roof system design, detailing and specification, then a qualified roof consultant with proven experience in single-ply membranes should be retained. Roof systems and their integration into the impinging building elements need to be designed, detailed and specified appropriately for the building’s intended use and roof function. By way of example, we at Hutchinson Design Group typically design roof systems for a 40- to 50-year service life (see Figure 1); the warranty at that point is nice, but almost immaterial. Typical specifications, which are project specific, cover all the system components and their installation. They are typically 30 pages long and call out robust and enhanced material installations.

More Than the Code

I recently had a conversation with a senior member of a very large and prominent architectural firm in the Chicago area and inquired about how they go about designing the roof systems. The first thing he said was, “We do what is required by code.”

Photo 1: The roof drain sump pans shown here were provided and installed by the plumbing contractor, not the steel deck installer. Having the roof drain level with the top of the roof deck allows for a proper integration of the roof drain and roof system.

What I heard was, “We give our clients the absolute poorest roof the code allows.” An OMG is allowed here again. Does it really need to be said again that the code is a minimum standard — as some would say, the worst you are allowed to design a building by law? Maybe you didn’t realize it, but you are allowed to design above the code. I know this will shock a few of you, but yes, it’s true. Add that extra anchor to prevent wood blocking from cupping. Add extra insulation screw fasteners to improve wind uplift resistance; if too few are used, you may meet the code, but your insulation will be susceptible to cupping. Add that extra bead of polyurethane adhesive. (If I specify 4 inches on center, then perhaps by mid-day, on a hot and humid day, I might get 6 inches on center — as opposed to specifying 6 inches or 8 inches on center, and getting 12 inches on center in spots.) Plan for construction tolerances such as an uneven decks and poorly constructed walls. Allow for foot traffic by other trades. These types of enhancements come from empirical experiences — otherwise known as getting your butt in the ringer. Architects need more time on the roof to observe what goes on.

It’s About Doing What is Right

Doing it right the first time isn’t all that difficult, and it’s certainly less stressful than dealing with the aftermath of doing so little. The cost of replacing the roof in the future could easily be more than double the original cost. Twenty years ago, I

Figure 3: Coordinating with the plumbing engineer, like coordinating with the mechanical engineer, is a requirement of best practices. In this drain detail, we can see the sump pan is called out correctly, and the roof drain, integration of the vapor barrier, extension ring, etc., are clearly defined. Photos: Hutchinson Design Group

chaired an international committee on sustainable low-slope roofing. At that time, the understanding of sustainability was nil, and I believe the committee’s Tenets of Sustainability, translated into 12 languages, helped set the stage for getting designers to understand that the essence of sustainability is long-term service life. That mantra seems to have been lost as a new generation of architects is at the helm. This is unfortunate, as it comes at a time when clients no longer ask for sustainable buildings. Why? Because they are now expected. The recent rash of violent and destructive storms — hurricanes, hail, intense rain, high winds and even wildfires — have resulted in calls for improvement. That improvement is called resiliency. If you have not heard of it, you are already behind. Where sustainability calls for a building to minimize the impact of the building (roof) on the environment, resiliency requires a building (roof) to minimize the impact of the environment on the building. This concept of resiliency requires designing a roof system to weather intense storms and to be easily repaired when damaged. (Think of Puerto Rico and consider how you would repair a roof with no power, limited access to materials, and manpower that might not be able to get to your site.)

Achieving resiliency requires the roof system designer to:

  1. Actually understand that roofs are systems and only as good as their weakest link. Think metal stud parapet and horizontal base anchor attachment; only forensic consultants and attorneys like to see screws into modified gypsum boards.
  2. Eliminate your old, out-of-date, incorrect details. Lead vent flashing and roof cement cannot be used with single-ply membrane.
  3. Design the roof system integration into associated barrier systems, such as where the roofing membrane (air/vapor retarder) meets the wall air barrier. You should be able to take a pencil and draw a line over the wall air barrier, up the wall and onto the roof without lifting it off the sheet. If you cannot, you need to redesign. Once you can, you need to consider constructability and who may get there first — the roofer or air barrier contractor. Then think material compatibility. Water-based air barrier systems don’t react well when hit with a solvent-based primer or adhesive.

    Photo 2: This roof drain is properly installed along with 6 inches of insulation and a cover board. The drain extension ring is 1/2 inch below the top of the cover board so that the water falls into the drain and is not held back by the clamping ring, resulting in ponding around the roof drain.

    Perhaps the roofing needs to be in place first, and then the air barrier brought over the top of the roofing material. This might require a stainless-steel transition piece for incompatible materials. Maybe this requires a self-adhering membrane over the top of the roof edge prior to the roofing work, as some membranes are rather rigid and do not bend well over 90-degree angles. You as the designer need to design this connectivity and detail it large and bold for all to see.

  4. Design the roof system’s integration into the impinging building elements, including:
  • Roof curbs for exhaust fans: Make sure they are insulated, of great enough height, and are not installed on wood blocking.
  • Rooftop unit (RTU) curbs: The height must allow for future re-roofing. Coordinate with the mechanical engineer regarding constructability – determine when the curb should be set and when the HVAC unit will be installed. Roof details should be on both the architectural and mechanical drawings and show the same curb, drawn to scale. Be sure the curb is insulated to the roof’s required R-value. Avoid using curb rails to support mechanical equipment. The flashing on the interior side of the rails may be inaccessible once the equipment is placed. Use a large curb where all four sides will remain accessible.
  • Piping penetrations: Detail mechanical piping penetrations through the roof and support of same, where insulation and waterproofed pipe curbs are needed (see Figure 2). If you are thinking pourable sealer pocket, stop reading and go sign up for RCI’s Basics of Roof Consulting course.
  • Roof curbs, RTU, pipe curbs and rails: Coordinate their location and show them on the roof plan to be assured that they are not inhibiting drainage.
  • Roof drains: Coordination with the plumbing engineer is essential. Sump pans should be installed by the plumbing contractor, not the steel deck installer (see Photo 1), and the location should be confirmed with the structural engineer. Be sure drains are located in the low point if the roof deck is structurally sloped — and if not, know how to design tapered insulation systems to move water up that slope. Do not hold drains off the deck to meet insulation thickness; use threaded extensions. Be sure any air/vapor barrier is integrated into the curb and that the insulation is sealed to the curb. I like to hold the drain flange a half-inch down below the insulation surface so that the clamping ring does not restrain water on the surface. Owners do not like to see a 3-foot black ring at the drain, where ponding water accumulates debris (see Figure 3 and Photo 2).
  1. Understand the roof’s intended use once the building is completed. Will the roof’s surface be used for anything besides weather protection? What about snow removal? Will there be excessive foot traffic? What about mechanical

    Photo 3: Gaps between the roof insulation and roof edges, curbs and penetrations are prevalent on most roofing projects and should be sealed with spray foam insulation as seen here. It will be trimmed flush once cured.

    equipment? Photovoltaic panels? Yes, we have designed roofs in which a forklift had to go between penthouses across the roof. Understanding how the roof will be used will help you immensely.

  2. Understand the construction process and how the roof might be used during construction. It is amazing how few architects know how a building is built and understand construction sequencing and the impact it can have on a roof. I firmly believe that architects think that after a lower roof is completed, that the masons, carpenters, glazers, sheet metal workers, welders, pipe fitters, and mechanical crews take time to fully protect the newly installed systems (often of minimal thickness and, here we go again, without a cover board — OMG) before working on them. I think not. Had the architect realized that temporary/vapor retarders could be installed as work surfaces, getting the building into the dry and allowing other trades to trash that rather than the finished roof, the roof system could be installed after those trades are off the roof.
  3. Coordinate with other disciplines. Roof systems cannot be designed in a vacuum. The architect needs to talk to and involve the structural, mechanical and plumbing engineers to ensure they realize the importance of essential details. For example, we cannot have steel angle around the drain whose flange rests on the bar joist, thus raising the roof deck surface at the roof drain. Ever wonder why you had ponding at the drain? Now you know. I attempt to always have a comprehensive, specific roofing detail on the structural, mechanical and plumbing sheets. I give the other disciplines my details and ask that they include them on their drawings, changing notes as required. That way, my 20-inch roof curb on the roof detail is a 20-inch curb on the mechanical sheets — not a standard 12-inch curb, which would more often than not be buried in insulation.
  4. Detail, detail, detail, and in case you glossed over this section, detail again. Make sure to include job-specific, clearly drawn details. Every condition of the roof should be detailed by the architect. Isn’t that what the client is paying for? Do not, as I once saw, indicate “RFO” on the drawings. Yes, that acronym stands for “Roofer Figure Out.” Apparently, the roofer did not figure it out. I enjoyed a nice Hawaiian vacation as a result of my work on that project, courtesy of the architect’s insurance company. How do you know that a condition works unless you design it and then draw it to scale?

    Figure 4: Insulation to curbs, roof edge and penetrations will not be tight, and to prevent a thermal short, the gaps created in construction need to filled with spray foam, as noted and shown here in this vent detail. Photos: Hutchinson Design Group

    I’ve seen roof insulation several inches above the roof edge because, OMG, the architect wanted gravel stop and forgot about camber. Not too big a deal (unless of course it’s a large building) to add several more layers of wood blocking and tapered edge strips at the now high wood blocking in the areas that were flush, but now the face of the roof edge sheet metal needs to increase. But what if the increase is above the allowable ANSI-SPRI ES1 standard and now a fascia and clip are required? You can see how the cost spirals, and the discussion ensues about who pays for what when there is a design error.

  5. Develop comprehensive specifications that indicate how the roof system components are to be installed. This requires empirical knowledge, the result of time on the roof observing construction. It is a very important educational tool that can prevent you, the designer, from looking like a fool.

Components

Best practices for single-ply membranes, in addition to the design elements above, also involve the system components. Below is a listing of items I feel embodies best practices for single-ply roof system components:

  1. Thicker membranes: The 45-mil membrane is insufficient for best practices, especially when one considers the thickness of the waterproofing over scrim on reinforced sheets. A 60-mil membrane is in my opinion the best practices minimum. Hear that? It’s the minimum. You are allowed to go to 75, 80 or 90 mils.
  2. Cover boards: A cover board should be specified in fully adhered and mechanically attached systems. (Ballasted systems should not incorporate a cover board.) Cover boards have enhanced adhesion of the membrane to the substrate over insulation facers and hold up better under wind load and hail. Cover boards also protect the insulation

    Photo 4: The greatest concern with the use of polyurethane adhesives is that the insulation board might not be not fully embedded into the adhesive. Weighting the boards at the corners and center with a minimum of 35 pounds for 10 minutes has proven to work well in achieving a solid bond.

    from physical damage and remain robust under foot traffic, while insulation tends to become crushed. Cover boards are dominated by the use of mat-faced modified gypsum products. Hydroscopic cover boards such as fiberboards are not recommended.

  3. Insulation: Now here is a product that designers seldom realize has many parts to be considered. First, let’s look at compression strength. If you are looking to best practices, 25 psi minimum is the way to go. The 18-psi insulation products with a fiber reinforced paper facer can be ruled out entirely, while 20 psi products are OK for ballasted systems. Now let’s look at facers. If you think about it for a second, when I say “paper-faced insulation,” you should first think “moisture absorbing” and secondly “mold growth.” Thus paper-faced products are not recommended to be incorporated if you are using best practices. You should be specifying the coated glass-faced products, which are resistant to moisture and mold resistant. A note to the manufacturers: get your acts together and be able to provide this product in a timely manner.

Additional considerations regarding insulation:

  • Insulation joints and gaps: You just can’t leave joints and gaps open. Show filling the open joints at the perimeter and curbs and around penetrations with spray foam in your details and specify this as well (see Photo 3 and Figure 4).
  • Mechanical attachment: Define the method of attachment and keep it simple. On typical projects, I commonly specify one mechanical fastener every 2 square feet over the entire roof (unless more fasteners are needed in the corners). Reducing the number of fasteners in the field compared to the perimeter can be confusing for contractors and the quality assurance observer, especially when the architect doesn’t define where that line is. The cost of the additional screws is nominal compared with the overall cost of the roof.
  • Polyurethane foam adhesive: Full cover spray foam or bead foam adhesive is taking over for asphalt, at least here in the Midwest, and I suspect in other local markets as well. The foam adhesive is great. It sticks to everything: cars, skylights, clerestories, your sunglasses. So, it is amazing how many insulation boards go down and don’t touch the foam. You must specify that the boards need to be set into place, walked on and then weighted in place until set. We specify five 35-pound weights (a 5-gallon pail filled with water works nicely), one at each corner and one in the middle for 10 minutes (see Photo 4). Yes, you need to be that specific.
  1. Photo 5: The design of exterior walls with metal studs that project above the roof deck is a multi-faceted, high-risk detail that is often poorly executed. Here you can see a gap between the deck and wall through which warm moist air will move and result in the premature failure of this roof. The sheathing on the wall cannot hold the horizontal base anchor screw, and the joints in the board allow air to pass to the base flashing, where is will condense. This is the type of architectural design that keeps on giving — giving me future work.

    Vapor/air barrier: A vapor air barrier can certainly serve more than a function as required for, say, over wet room conditions: pools, locker rooms, kitchens, gymnasiums. We incorporate them in both new construction and re-roofing as a means of addressing construction trade phasing and, for re-roofing, allowing time for the proper modification of existing elements such as roof edges, curbs, vents, drains, skylights and pipe curbs. Be sure to detail the penetrations and tie-ins with wall components.

  2. Deck type: Robust roof decks are best. Specify 80 ksi steel roof decks. Try staying away from joint spacing over 5 feet. Decks should be fully supported and extend completely to roof edges and curbs.
  3. Roof edge design: A key aesthetic concern, the termination point for the roof system, the first line of defense in regard to wind safety — the roof edge is all of these. The construction of the roof edge on typical commercial construction has changed drastically in the last 20 years, from brick and block to metal stud. Poorly designed metal stud parapets will be funding my grandkids’ college education. The challenge for the metal stud design is multifaceted: It must close off the chimney effect, prevent warm moist air from rising and condensing on the steel and wall substrate, create an acceptable substrate on the stud face in which to accept base anchor attachment, and — oh, yes — let’s not forget fire issues. Tread lightly here and create a “big stick” design (see Photo 5).
  4. Roof drains and curbs: As discussed above, there is a great need for coordination and specific detailing here. The rewards will be substantial in regard to quality and efficiency, minimizing time spent dealing with “what do we do now” scenarios.
  5. Slope: Design new structures with structural roof deck slope, then fine tune with tapered insulation.

Final Thoughts

Best practices will always be a balancing act between cost and quality. I believe in the mantra of “doing it right the first time.”

The industry has the material and contractors possess the skill. It’s the design and graphic communication arm that needs to improve to keep everyone working at the top of their game.

Designers, get out in the field and see the results of your details. See firsthand how a gypsum-based substrate board on a stud wall does not hold screws well; how a lap joint may not seal over the leading edge of tapered insulation; how the roof either ponds water at the roof drain or doesn’t meet code by drastically sumping; or how the hole cut in the roof membrane for the drain might be smaller than the drain bowl flange, thus restricting drainage. Seeing issues that the contractors deal with will help you as the designer in developing better details.

Contractors, when you see a detail that doesn’t work during the bidding, send in an RFI and not only ask a question, but take the time to inform the architect why you don’t think it will work. On a recent project here in Chicago, the architect omitted the vapor retarder over a pool. The contractor wrote an explicit explanation letter and RFI to the architect during bidding, and the architect replied, “install as designed.” In these situations, just walk away. For me, this is future work. A local contractor once told me, “I don’t get paid to RFI, I get paid to change order.” He also said, “If I ever received a response to an RFI, I would frame it!”

Manufacturers, too, can raise the bar. How about prohibiting loose base flashings at all times, and not allowing it when the salesman says the competition is allowing it. Have contractors on the cusp of quality? Decertify them. You don’t need the hassles. Owners don’t need the risk.

Seek out and welcome collaboration among contractors, roof systems designers, knowledgeable roof consultants, and engineers. Learning is a lifelong process, and the bar is changing every year. Too often we can be closed off and choose not to listen. At HDG, I am proud to say we have the building owners’ best interests at heart.

By all working together, the future of single-ply membranes can be enhanced and the systems will be retained when the next generation of roof cover arrives — and you know it will.