Fire Resistance Is Built into Polyiso’s Polymer

ENRGY 3.E from Johns Manville

ENRGY 3.E from Johns Manville

ENRGY 3.E from Johns Manville is the next generation of polyisocyanurate roof-board insulation whereby the fire resistance has been engineered into the polymer backbone without the need for added halogenated flame retardants. Unlike conventional halogenated flame retardants that are free un-bonded plasticizers mixed with the foam, the reactive polymer modifier used to produce ENRGY 3.E is a non-halogenated organo-phosphorus monomer that chemically reacts and bonds directly to the polymer network. This results in the polyiso performance attributes of the existing ENRGY 3 while being inherently fire-resistant and meeting all current fire codes.

Georgia-Pacific Gypsum Redesigns DensDeck Website

With the goal of providing more information and resources, Georgia-Pacific Gypsum has redesigned its website dedicated to its favorite roof board—DensDeck.

The new DensDeck website has targeted information that lets busy professional fine just what they need to know, quickly and effortlessly. Roofing consultants, Architects, Specifiers, Building Owners/Facility Managers or Roofing Contractors can click unto their specific section to find relevant content targeted to the interests and needs of those construction professionals.

The site was also designed to provide the best visual content for tablets and smart phones, making it much more accessible for highly-mobile design and construction personnel.

Visitors can also now sign up for eBlasts, with the option of providing a profile which will allowing Georgia-Pacific Gypsum to provide just that eBlast content which they would be interested in to make their roofing related tasks easier.

DensDeck.com also offers videos, case studies, technical resources and more on topics made to facilitate the roofing process for professionals.

Several ‘Sandwich’ Roof Assemblies Mitigate Sound Transfer

We all want a roof over our heads to protect us from the cold winter months, hot summer months and precipitation year round. How much thought goes into the sound-control construction of a roof, though? Have you considered the acoustic properties of your roofing system? Admittedly, acoustics is not a topic that many roofing contractors think about. The construction of a roof, however, can have a significant impact on the sound quality of the building interior. While this may not seem important in every project, it can be a critical element of the design for concert halls, theaters, auditoria and even school classrooms.

Sound Isolation

The acoustics of a space depend on many criteria, including sound isolation, sound reflection, impact noise and sound transfer. In many cases, particularly in noisy, urban environments, there is a need to prevent loud outside noises, such as traffic, sirens and airplane noise, from entering quiet spaces. Sound isolation depends on the entire envelope of a space, including external walls, windows and roofs.

Green roofs, particularly the “intensive” version, which includes several inches of heavier-weight soil, can provide effective sound control.

Green roofs, particularly the “intensive” version, which includes several inches of heavier-weight soil, can provide effective
sound control.

Historically, roofs over sound-sensitive spaces have been built with fairly dense materials, such as concrete, which by themselves are relatively effective in blocking sound transfer. As construction methods have developed, however, more lightweight construction is being used. If thought and care are not given to the assembly, these lightweight construction methods can cause serious issues with acoustics. Rain noise, mechanical noise and other exterior sounds can all transfer readily through a thin, lightweight roofing system.

In an effort to use lighter-weight construction, a “sandwich” assembly may be used to mitigate sound transfer. Similar to an Oreo cookie, a sandwich assembly’s outer layers are comprised of a heavy, dense material, and the inner filling consists of insulation and/or airspace. The materials of this assembly can differ from concrete to roofing board, rigid insulation to fibrous insulation, gypsum board to acoustic ceiling tiles. The components can be combined in a variety of ways, each with varying levels of sound isolation.

One of the principle phrases often heard when discussing sound isolation is “mass air mass”, which refers to the separation of two bodies of mass by an air space. The greater the mass and the deeper the air space, the more sound isolation will result. For this reason, a heavy mass, such as 5-inch concrete, followed by a deep air space, such as an 18- to 24-inch ceiling cavity in which ducts are run, followed by a continuous layer of drywall ceiling will provide a high level of sound isolation. Additional steps, like adding sound-absorptive material to the air space and/or using resilient connections when supporting drywall, further improves the sound isolation of the assembly.

Sandwich Roof Assemblies

Several sandwich roof assembly approaches are possible, including:

Good: Multiple layers of dense roofing board (at 2.5 psf per board, a final density of 10 psf or four-ply is often recommended) on either side of insulation, which ideally would be a sound-absorptive fibrous fill, like mineral wool, can reduce sound transmission. This approach is similar to a “floating floor”, often used in interior spaces to isolate sound transfer from one room to another. (Equivalent Sound Transmission Class, or STC, ratings can range from low 50s to low 60s, depending on whether a ceiling is included below the deck.)

Drywall ceilings hung on resilient hangers in conjunction with a lightweight roofing system provide even greater sound isolation by virtue of the resilient connection or “decoupling” of the drywall layer from the rest of the building structure.

Drywall ceilings hung on resilient hangers in conjunction with a lightweight roofing system provide even greater sound isolation by virtue of the resilient connection or “decoupling” of the drywall layer from the rest of the building structure.

Good: Green roofs, particularly the “intensive” version, which includes several inches of heavier-weight soil, can provide effective sound control. These can be part of a sandwich approach with airspace or rigid insulation between soil and a more-dense roofing material, similar to the roofing board described in the previous example. The mass-air-mass combination is similar to the approach just mentioned, and the benefits of green roofs appeal to many building owners for a multitude of reasons, including minimizing urban heat islands and storm-water management.

Good: A 5-inch slab of normal-weight concrete (150 pcf) has a density of 62 psf. This tried-and-true method is still used regularly and often proves to be the most cost-effective method of enclosing a space. The best sound isolation will occur if this is used in conjunction with a ceiling below, but on its own it still provides a reasonable level of isolation in many environments. This isn’t technically a sandwich system unless paired with a ceiling below or a green roof above. (Equivalent STC ratings can range from low 50s to low 80s. The highest ratings require pairing a resiliently hung ceiling with the concrete, as described under “Multi-function Roof Assemblies”.) IMAGES: Threshold Acoustics LLC [Read more…]

Insulation Offers Acoustic Properties

ROXUL TOPROCK DD Plus

ROXUL TOPROCK DD Plus

Designed for commercial and industrial roof insulation applications, ROXUL TOPROCK DD Plus is a dual-density mineral wool board insulation with a rigid upper layer for durability and enhanced strength. The product, which is suitable for new construction and reroofing applications, is impregnated with a bitumen layer compatible with torch- or mop-applied membrane. The dimensionally stable insulation is non-combustible, will not warp or cup, features high impact resistance and low moisture absorption, offers acoustic properties, and is made of natural and recycled materials.

New Family of Roof Boards for Commercial Assemblies

National Gypsum's DEXcell product line features high-performance roof boards for commercial roofing systems.

National Gypsum’s DEXcell product line features high-performance roof boards for commercial roofing systems.

National Gypsum has launched DEXcell, a new family of high-performance roof boards for commercial roofing systems.

The DEXcell brand family includes three products:

    1. DEXcell brand Glass Mat Roof Board
    2. DEXcell brand FA Glass Mat Roof Board (for fully adhered membrane systems)
    3. DEXcell brand Cement Roof Board (a lightweight cement board for the roofing industry that will withstand prolonged exposure to moisture)

National Gypsum’s new DEXcell family has gone through rigorous third-party testing and carry a number of approvals and meet various industry standards to resist mold and provide a fire barrier for commercial structures, such as schools, hospitals and hotels.

DEXcell Glass Mat Roof Board and DEXcell FA Glass Mat Roof Board are mold resistant gypsum boards designed for use as a coverboard and/or thermal barrier in commercial roofing applications. Both are produced in 1/4-, 1/2- and 5/8-inch thicknesses and 4-foot wide in 4- and 8-foot lengths. These products score and cut easily and are specially coated on the front, back and sides for easy handling.

DEXcell Glass Mat Roof Board is ideally suited for mechanically fastened roof systems and has coated fiberglass facers with an enhanced gypsum core.

DEXcell FA Glass Mat Roof Board is designed for fully adhered roof systems, and is manufactured with heavy-duty coated fiberglass facers with an enhanced gypsum core.

DEXcell brand Cement Roof Board is a lightweight moisture- and mold-resistant cement board designed for use as a cover board and/or thermal barrier in all commercial roofing applications. It provides a fire barrier and a thermal barrier. These boards are manufactured of Portland cement, lightweight aggregate and glass mesh that provide an exceptionally hard, durable surface. It is produced in 7/16-inch thickness and 4-feet wide in 4- and 8-foot lengths.