Techniques for insulating exterior walls in commercial buildings have received considerable attention in recent years for many good reasons. Energy codes are requiring higher thermal performance values in walls. Green building standards and energy efficiency programs seek to exceed the minimums called for in the codes. Building owners are seeking to control energy consumption and associated expenses while still controlling construction costs. All of this has architects and other building professionals seeking solutions for proven and effective exterior wall assemblies that provide the thermal performance needed. Among the emergent and popular choices, spray foam insulation is being used to address a number of thermal performance needs in different types of wall assemblies.

Spray Foam Insulation Overview

When selecting building insulation, architects have a broad range of products to choose from. Foam insulation products, whether used in board products or sprayed in place, have typically and rather consistently been shown to provide equal or greater insulation performance per inch than other products such as batt or loose fill insulation. While foam board products are common and widely used in wall and roof assemblies, foam that is sprayed in place in the field is becoming more widespread for a variety of performance and construction ease reasons. In particular, wall assemblies in commercial buildings that use spray foam insulation have evolved to be a very attractive and pervasive technology with greater flexibility in regard to both design and installation.

Right up front, it should be noted that unlike traditional insulation products, spray foam insulation is mixed and formed in the field. Most of these systems require two distinct ingredients that are combined on site using specific equipment associated with a manufactured foam product. Typically, equipment is mounted in a trailer or truck with flexible hoses carrying the needed ingredients from there to a handheld gun that both mixes and sprays the combined product onto the surfaces being insulated. As soon as the two parts are mixed, a chemical reaction begins causing the liquid mixture to foam, expand, and eventually harden. This customized on-site application means that the sprayed insulation readily conforms to the shape and geometry of the surfaces it is being applied to while its chemical make-up provides the needed properties for it to adhere to those surfaces.

Continuous spray foam insulation is suitable for use in commercial buildings to create superior thermal performance, air sealing, and moisture control. Photo courtesy of ICYNENE, Inc.

Because of this full custom on-site application, spray foam insulation is generally found to be effective at boosting the energy performance of wall assemblies in multiple ways. First, it fills completely the spaces being insulated. In typical stud wall cavities, that means that irregularities from framing can be filled around rather than restricting or compromising the amount of insulation installed. This complete filling is thus unhindered by unusual conditions that can be a significant challenge for other insulation products that are pre-cut or pre-formed in shapes that differ from field conditions. Second, spray foam has been shown to hold its shape over time such that sagging, settling, and other potential incomplete insulation installations that cause gaps or voids can be readily overcome with spray foam insulation. Third, it significantly reduces air leakage, thus reducing unwanted air infiltration. In fact, spray foam insulation has been used in many buildings specifically to seal openings, penetrations, and around doors and windows. Because of this air sealing quality, it can also be an effective barrier that minimizes airborne moisture transfer. Keeping unwanted moisture out of wall assemblies has long been a goal of successful design, thus these properties are significant indeed. Overall, the use of spray foam insulation, then, goes beyond just R-values and truly addresses a comprehensive way to optimize energy efficiency.