Three Polyiso Roof Insulation Options to Simplify Your Next Job

Pre-fabricated roof sumps direct water to a center drain point, helping to ensure proper drainage and minimizing installation time. Photos: Hunter Panels

As a roofing professional, you undoubtedly are familiar with polyiso insulation, as it is used in 70 percent or more of the commercial roofs in North America. Polyiso is popular with roofing professionals because it offers a high R-value per inch, is affordable, readily available, compatible with many roofing systems and meets both FM 4450 and UL 1256.

While you likely have specified or installed flat stock polyiso products, you might be less familiar with specialized product make-ups, which can help you simplify roof insulation jobs. Three options to be aware of are:

  1. Tapered systems
  2. Pre-cut hips and valleys
  3. Pre-fabricated sumps

Tapered Systems

As roofing professionals know, water is the enemy of the roof assembly. To prevent ponding and provide a positive slope to drain, polyiso insulation manufacturers offer sloped panels. Tapered polyiso typically comes in 4-foot-by-4-foot or 4-foot-by- 8-foot panel sizes, and in various compressive strengths. Commonly available slopes (per foot) include 1⁄16 inch, 1⁄8 inch, 3⁄16 inch, 1⁄4 inch, 3⁄8 inch and 1⁄2 inch. Tapered systems range from two-panel to eight-panel repeats, with such systems including varying thicknesses of flat polyiso insulation to complete the taper profile.

Photos: Hunter Panels

Tapered polyiso insulation installs similar to flat stock polyiso insulation, using adhesives or fasteners. As with multi-layer flat stock installations, when installing tapered products, crews should stagger the joints between layers to reduce potential pathways for airflow and condensation within the insulation layers.

Full-service polyiso manufacturers can design a tapered insulation layout based on the roof plan and specified R-value. They then will provide shop drawings showing where to place each tapered and flat stock panel to ensure positive slope and effective drainage across the entire roof.

Pre-Cut Hips and Valleys

In addition to the one-way sloped tapered panels discussed above, roofing professionals have access to pre-cut hips and valleys made of polyiso insulation. The hips and valleys help direct water on more complex roof designs. Well-equipped manufacturers will custom design and fabricate pre-cut, one-piece polyiso hips and valleys to meet your jobsite requirements including slope, and minimum and maximum thicknesses.

While crews can form hips and valleys by field-cutting tapered panels, ordering the pre-cut, one-piece panels reduces labor time and costs, as well as dumpster fees. It also prevents material waste caused by cutting errors.

Pre-Fabricated Sumps

Going a step farther in slope complexity, and further reducing ponding water, some polyiso insulation manufacturers offer pre-fabricated roof sumps. Commonly available as 4-foot-by-4 foot panels that ship flat, pre-fabricated sumps direct water from four directions to a center drain point. Some manufacturers also offer 8-foot-by-8-foot hinged sumps for greater design flexibility. All of these sumps offer a variety of starting thicknesses at the drain from 1/2 inch to 2 inches.

Choosing a Polyiso Supplier

Roofing professionals can obtain polyiso roof insulation from several suppliers. Which one is right for you? Following are a few factors to consider to help simplify your next roofing job.

  • Access to technical support: Some polyiso manufacturers provide customers with a variety of technical services. Having access to designers and estimators who work every day with specialized polyiso products takes the guesswork out of the process for you, saving time and money while helping ensure a high-quality roof.
  • Ready availability: Choosing a supplier with facilities throughout the country helps ensure timely access to specialty polyiso insulations when you need them.
  • Training support: To help your crews get up to speed faster on working with specialized polyiso roof insulation systems, look for a manufacturer that offers training support — whether via online videos, in person or on the jobsite.

Cap Sheet Reflects Ultraviolet Rays, Absorbs Less Heat

The RCap Plus cap sheet features reflective white granules embedded into the membrane to reflect ultraviolet rays and absorb less heat.

The RCap Plus cap sheet features reflective white granules embedded into the membrane to reflect ultraviolet rays and absorb less heat.

Malarkey Roofing Products has introduced the RCap Plus cap sheet for low slope, commercial roofing systems. It features reflective white granules embedded into the membrane to reflect ultraviolet rays and absorb less heat.

RCap Plus utilizes ground and packed granules, and these granules ensure more coverage in the membrane per square. Malarkey grinds the asphalt granules at its South Gate, Calif., manufacturing facility.

The solar reflectivity and limited heat absorption of the RCap Plus cap sheet are key design features of the product. RCap Plus meets CEC Title 24, Part 6 standards and has an initial Solar Reflectance Index (SRI) rating of 87. As part of a roof system, RCap Plus may help decrease energy costs used to cool the building and extend roof service life.

Lightweight Solar Panels Can Be Used On Flat Roofs

Beamreach Solar has introduced Sprint, a lightweight photovoltaic solar panel system for flat commercial roofs.

Beamreach Solar has introduced Sprint, a lightweight photovoltaic solar panel system for flat commercial roofs.

Beamreach Solar has introduced Sprint, a lightweight photovoltaic solar panel system for flat commercial roofs. Sprint can be installed on nearly all commercial roofs that cannot currently support heavy conventional solar systems, dramatically expanding the commercial solar power market. Featuring maximum power capacities ranging from 290 to 320 watts, Sprint integrates racking into the panel for quicker installation that requires no tools and no grounding. Sprint’s design also reduces the distance required between panel rows, enabling up to 30 percent more panels to be installed on a roof, increasing the solar system’s overall energy output. Sprint panels have been tested to support test loads up to 5,400 Pascals and withstand wind speeds of 115 mph. Sprint also comes with a 25-year linear output warranty and 10-year product warranty.

NRCA Supports Commercial Roof Depreciation Legislation

The National Roofing Contractors Association (NRCA) strongly supports bipartisan legislation introduced in Congress on May 22 to reform the outdated depreciation schedule for commercial roofs. This legislation, which replaces the current 39-year depreciation schedule with a 20-year schedule, will remove an obstacle in the tax code that limits economic growth in the roofing industry, thus facilitating the creation of an estimated 40,000 new jobs among roofing contractors and manufacturers. It also will benefit millions of small businesses nationwide and advance energy efficiency within the commercial building sector.

NRCA wishes to commend Reps. Tom Reed (R-N.Y.) and Bill Pascrell (D-N.J.) for sponsoring the House bill (H.R. 4740) and Sens. Ben Cardin (D-Md.) and Mike Crapo (R-Idaho) for authoring the companion legislation (S. 2388) in the Senate. NRCA looks forward to working with these and other lawmakers to enact this legislation as the congressional tax-writing committees consider possible changes in tax policy that will help grow the economy and create jobs.

There has been a need for depreciation reform since the depreciation schedule for nonresidential property was increased from 15 to 39 years between 1981 and 1993. The average life span of most commercial roofs is only 17 years, according to a study by Ducker Worldwide. This has caused building owners to delay the full replacement of older, failing roofs in favor of limited, piecemeal repairs. Moreover, building owners who install new roofs before the current 39-year schedule has elapsed are required to depreciate roofs at different schedules, causing paperwork burdens for businesses.

This legislation will rectify this problem by providing the 20-year depreciation schedule for commercial roof retrofits that meet a benchmark energy-efficiency standard. Depreciation reform for energy-efficient commercial roofs will provide significant energy, environmental and economic benefits by reducing energy costs for businesses of all types that install new roofs.

Depreciation reform for commercial roofs enjoys the support of numerous business, labor and energy efficiency groups, including the National Roofing Contractors Association; United Union of Roofers, Waterproofers and Allied Workers; and the Polyisocyanurate Insulation Manufacturers Association. For more information, please contact NRCA’s vice president of government relations Duane Musser, or manager of federal affairs Andrew Felz at (202) 546-7584.