Building Science: Alternate insulation for multi-unit housing

Our first hurdles were the insulation listings and specs submitted by the architect to the planners. With the help of our cellulose manufacturer, we were able to locate listings that would satisfy every wall assembly except the floors.

February 15, 2013

The year was 1991. I was a custom home builder looking for ideas to heighten my awareness of energy-efficient designs and separate myself from the competition, so I attended the EEBA conference in Indianapolis. It changed my future. I met Graeme Kirkland, eventual founder of Icynene, sitting at a card table with a tricolor brochure and a block of soft-water blown foam. When I saw this material and was offered the chance to visit their headquarters, I took it. We built a urethane spray rig and became one of the first low-density foam contractors in the U.S.

Alternate superior design

New insulation systems and assembly design applications have historically evolved in the residential building market. Fiberglass insulation systems have dominated the commercial and residential market segments for decades.

Individual glass fibers are basically monolithic glass rods without a cellular core. Properly installed foam or cellulose insulation systems with cell cores typically maintain higher effective thermal resistance when subjected to significant temperature extreme and wind pressure differential. The individual microcells depending on cell adhesion or installed density help eliminate air movement and convection just by the nature of their design. This insulation microperspective is critical for us to understand the evolution of alternate methods of insulation design.

Information revolution

Insulation contractors with varying degrees of contracting or building science expertise have developed niche markets for new technologies such as water-blown low-density spray foams. Historically contractors, architects, and custom builders researching new systems have driven these lesser-known insulation methods to the forefront. Because the Internet has become a valuable research tool for multiple generations, homeowners have become a force in the selection of residential building systems.

Residential insulation design has evolved rapidly. Commercial insulation design has been slower to change due to the critical assembly listings necessary to satisfy structural fire or sound issues. Every wall, floor, or roof assembly design must be tested fully assembled to satisfy municipal planners. Architects have shied away from alternate insulation methods due to a lack of qualified contractors satisfying the public works’ licensing, bonding, and manpower issues necessary to maintain scheduling time frames.

Superior performing materials coupled with installation techniques that superseded the norm, as well as a stable shop of accomplished technicians, were necessary tools for us to survive a culture of indifference when it came to insulation and the lowest labor denominator typically associated with the trade.

Key to our survival was an extreme climate that was unforgiving to substandard insulation installation practices. Forged by the necessity to perform flawless insulation applications and comprehend the dynamics of roof design, we developed multiple system combinations and a consulting division to interact with architects, builders, and clients.

The job

The chance to bid on a job was presented to us by one of our region’s largest builders. This builder had experienced firsthand the liabilities associated with the insulation practices in our extreme climate. On one particular high-profile development, his company suffered multiple roof failures with devastating internal leakage. The only 70-plus units that did not fail had the framing and ductwork altered due to consulting and insulation packages designed by our company. This contractor wanted us to bid on a high-profile job in a more moderate climate for one of the largest multi-unit developers in the nation.

Our first hurdles were the insulation listings and specs submitted by the architect to the planners. All of the listings were typical fiberglass specifications. With the help of our cellulose manufacturer, GreenFiber, we were able to locate listings that would satisfy every wall assembly except the floors. The architect was pushing for the highest LEED certification possible, and my company was eager to satisfy the superior fiberglass-free thermal, sound, and fire assemblies we were accustomed to providing for the residential sector.

The team at GreenFiber began pursuing the necessary engineering and confirmed UL scheduling to satisfy the project time frames. UL M512 was accomplished two days before scheduled installation. It was a densely packed cellulose floor assembly that satisfied fire ratings exceeding one hour. The impact or IIC rating was 56 and the STC rating was 53. These values represent the safest and quietest floor assembly available for multi-unit design. LEED Platinum certification was achieved and a superior thermal and sound enclosure assembly accomplished. PR

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