Good building envelope design has received a great deal of attention in recent years for good reason. Creating wall, roof, and floor systems that are durable and long lasting as well as aesthetically and economically appropriate is the usual starting point. But there is also the critically important need to control what flows through those systems, such as heat, air infiltration, moisture, and sound. This is compounded by the fact that different building categories such as commercial, industrial, residential, or institutional will often have different requirements for the degree of control required for any one or all of these things. Further variations occur when looking at buildings in different climate zones or with different operating conditions. The key to a successful building envelope then becomes finding ways to combine the right materials into assemblies that can meet all of these varied requirements. Among the critical choices to be made, the selection of an insulation material used in an assembly will have a significant impact on the total performance of that assembly. In particular, the selection of spray foam insulation systems has been shown to be a very attractive and effective choice that can address all of the control issues related to heat, air, moisture, and sound transmission. Further, it is appropriate for use in wall, roof, and floor assemblies in buildings of all types from low-rise residential, through large-scale industrial or institutional, and mid- to high-rise commercial with equal abilities to perform very effectively in all cases.

Overview of Spray Polyurethane Foam Insulation

As the name indicates, spray polyurethane foam (SPF) insulation is a polyurethane product that is sprayed into openings or cavities in building envelope assemblies. It is in fact a two-component system of liquids that are mixed in the field and then spray applied where the resulting foam expands in place to fill cavities completely. This foam also has an adhesive quality that means it readily sticks to the substrate where it is applied. This combination of adhesive and expansion properties creates a very effective sealant against air infiltration as well as providing very good thermal performance. In fact, according to the Air Barrier Association of America (ABAA), many spray foam insulations, regardless of type, are classified as air barrier materials and recognized as the key component in tested air barrier assemblies.

SPF insulation is generally regarded as an environmentally responsible product primarily due to its excellent energy-efficiency benefits both as an effective thermal insulation and air sealant. The manufacture and application of these products is also accomplished with a zero-ozone depletion process, meaning that the outdoor environment is not unduly impacted. When it comes to indoor environmental quality, SPF insulation is in fact a type of in-organic plastic, so it has no food value for mold or mildew to grow and develop. This reduces the chance of mold occurring in the first place which cannot be assured with organic materials.

The field application process is really quite comparable to typical in-plant applications that have been used since the 1960s to insulate appliances such as dishwashers, refrigerators, and freezers. The only difference is that the equipment is placed into trucks and trailers to essentially make mobile factories. This highly specialized equipment commonly includes things like plural component proportioning units, compressors, a generator, and 200-300 feet of hose for applications in the field. These mobile factories can range from $60-$100K and the applicators that operate them need to be highly skilled technicians, definitely not from the local day labor shop. Across the spray foam insulation industry, quality control standards and training programs have been developed to train applicators, improve installation quality, and help SPF installations meet design and specification requirements.

Spray Polyurethane Foam (SPF) insulation installs readily, completely, and easily in buildings of all types. Photo courtesy of Demilec (USA) LLC

 

While all SPF insulation shares these general qualities, there are two distinct product types that are used in buildings: Low-Density, and Medium-Density. Each one has their own specific set of characteristics as described: