Firestone’s Enverge™ Cavity Wall Systems Provide Opportunity For Long-Term Energy Savings

By Chris Tobias, Business Development Manager – Cavity Wall Products
Firestone Building Products

When it comes to cavity wall products, it’s all about the wall assembly. That fact was a driving force when Firestone Building Products developed and introduced its new line of Enverge™ Cavity Wall Products, which benefits everyone involved in a given commercial building project: from architects to contractors to owners.

The portfolio includes: continuous insulation (CI) exterior wall insulation, air and vapor barrier and thru-wall flashing. These individual products work together to improve thermal performance and prevent thermal bridging in commercial buildings; whether utilized with metal panels, metal composite panels or masonry claddings. The system of products also helps designers and facility owners achieve continued energy efficiency.

Continuous Insulation

The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) defines CI as that which runs continuously over structural members. It is free of substantial thermal bridging, like rigid foam insulation above a roof deck, and aids thermal performance of a wall assembly.

Thermal bridging in metal framing is generally caused by the loss of heat that’s conducted by the steel members. The issue can present itself in the form of decreased interior surface temperatures and in more extreme cases, condensation and mold development. All of these effects can be prevented with a properly detailed CI installation.

Firestone Building Products Enverge CI Exterior Wall Insulations are available in two facer options: coated fiberglass mat facer and aluminum foil facer. Both types incorporate a proprietary foam technology that uses an HCFC-free blowing agent and does not contribute to the depletion of the ozone (non-ODP).

Additionally, the products offer low global warming potential (low-GWP) and are formaldehyde-free. Both rigid insulation panels consist of a specially formulated fire resistant closed-cell polyisocyanurate foam core laminated to their respective facer options. Enverge CI Exterior Wall Insulations offer a Class A, FSI ≤ 25 SDI ≤ 450, ASTM E 84 performance and meet code compliance wall assembly testing under NFPA 285.

Air and Vapor Barrier

Uncontrolled air movement through a wall assembly will have negative, lasting effects not only on how a building functions, but on its energy expenditure, interior air quality and occupants’ comfort levels. That’s where the Enverge™ Air and Vapor Barrier comes into play. Air barriers do just what their name implies: Control the unintended movement of air into and out of a building enclosure, according to a white paper by the Air Barrier Association of America (ABAA).

“Air-barrier systems are made up of a number of materials that are assembled to provide a complete barrier to air leakage through the building enclosure,” the ABAA states. “A building enclosure includes all ‘six sides’ of a building — exterior walls, roof and foundation floor — and may also include separations within the structure.”

The Enverge Air and Vapor Barrier is an asphalt-based, self-sealing wall barrier that combats all the effects of air leakage by creating an impermeable barricade for a building’s shell. Its consistent membrane thickness yields energy savings.

Before installing the product, surfaces must be primed with an Enverge primer. Other considerations to maximize installation performance include:

• Removing the release liner at a 45-degree angle in 3-inch increments to promote correct alignment and installation continuity
• Firmly rolling from the center of the membrane to its outside edge to create maximum adhesion
• Ensuring seams overlap a minimum of 2 inches for most effective coverage
• Allowing the membrane to self-seal around mechanical fasteners to minimize air leakage around open gaps
• Using foil flashing tape, if preferred, which can also be utilized to seal penetrations

Thru-Wall Flashing

Thru-wall flashing products selected by design professionals must be durable and invulnerable to degradation or general failure. They come in a variety of options, from galvanized metal to lead-coated copper flashings and drips.

Firestone Building Products Enverge™ FlashGard™ Thru-Wall Flashing, a high-performance, flexible membrane is a premier choice for masonry wall assemblies. This tough, resilient EPDM membrane has excellent thermal and dimensional stability, as well as superior resistance to weathering, ozone and ultraviolet radiation. All of those features are necessary to ensure minimal lifetime maintenance in commercial building projects.

Not unlike other industry options, Firestone Building Products Enverge FlashGard Thru-Wall Flashing is aimed at protecting against water damage. Its superiority lies in many characteristics, including that it is puncture, tear and corrosion resistant. The material can remain exposed on a job site for an extended period of time, eliminating the need for rework or construction delays. It also allows for year-round installation in all weather conditions starting at -49 degrees Fahrenheit and conforms readily to irregular shapes and contours.

Enverge FlashGard Thru-Wall Flashing installs in the mortar bed or attaches mechanically to a variety of substrates. It can be exposed at the edge or used in conjunction with a drip-edge. All installation options require no more than standard construction tools.

Understanding the complete building envelope is crucial to even the most simplistic commercial building designs and evaluating the key elements that must be considered with a cavity wall assembly. Heat, air and moisture — both vapor and liquid — have a definite impact on how a cavity wall assembly should be designed and constructed. Once these elements have been addressed, a cavity wall assembly will increase energy efficiency, meet the required energy and fire code standards and provide cost-savings over the life of the building.

About Holcim Building Envelope Division

Holcim Building Envelope produces a broad range of exterior building products, including the Elevate™ (formerly Firestone) lineup of metal roof and wall panel systems. To learn more, visit or www.holcimelevate.com.