INSULATION MATERIALS

Choosing the right insulation product for your project can have a large impact on your home or building’s energy efficiency, comfort, and indoor air quality. Here are several techniques that are available, many of which we install.

Open-Cell Spray Foam
Closed-Cell Spray Foam
Cellulose
Fiberglass
Tri-Polymer Foams
Mineral Wool
Cotton Bats

Open-Cell Spray Foam

Open-cell spray foam is one of the best all-purpose home insulation materials.
It is a lightweight semi-rigid polyurethane foam insulation product that has roughly the consistency of a nerf ball or a seat cushion, although it will compress permanently under pressure. Its open cell structure will allow liquid water to pass through without absorption but resists the flow of air, and with that water vapor.

Closed-Cell Spray Foam

Closed cell spray foam is a heavier rigid polyurethane foam insulation that provides a higher R value and a complete air and moisture barrier. The material is also called rigid, or 2-lb density foam. This product is typically best for exterior applications, below slabs and on masonry foundations, or in interior applications like pool rooms where moisture drive may be an issue. It’s properties as a moisture barrier helps resist the intrusion of water, and it’s rigidity can also be a benefit.

It should be noted that we do not recommend the application of closed-cell foam to wood members. It is inflexible and may separate from wood that is moving, and also will not allow moisture intrusion in wood framing to be detected before significant damage occurs.

Closed cell spray foams currently uses blowing agents with extremely high greenhouse gas potential. Decades of carbon savings will be required to offset these blowing agents. New blowing agents that are more benign and foam technology in general are under constant R&D, so we are hopeful this issue will be resolved soon.

Cellulose

Cellulose insulation is a fiberous material that is made from shredded newspaper, borates, and glue. The material can be a good solution for insulating a ceiling economically. With enough depth or a good caulking package cellulose can perform quite well. Some applicators also mix cellulose with water and apply the material vertically in stud cavities. This application method can result in settling over time, and when installing cellulose in wall cavities, we prefer “dense-packing”, which provides superior air flow resistance without future settling. While we believe foam can be a better product in many situations, cellulose is still an excellent insulation material.

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Fiberglass

Fiberglass is a fibrous material made of woven strands of glass. This material is the most commonly used for insulation – and has made a significant contribution to energy efficiency, mainly because it is very inexpensive and is better than nothing. Fiberglass does nothing to stop the movement of air through a building frame, however, and in fact is often used as an air filter in HVAC systems. Since air movement is a serious component of energy loss in homes, the use of fiberglass as insulation can be questionable. We believe that there is enough fiberglass in the world, and do not offer this product.

Tri-Polymer Foams

There are several brands of shaving cream type foams that are used for wall injection and block fill. Typically these foams are known as “tri-polymer” foams and are water-based. These foams are easily installed into an existing cavity, and can be a profitable retrofit product relative to other retrofit products. Conversely, they are also prone to shrinkage or collapse as they dry. Having seen the results of these foams over time, we believe that they defeat one of the biggest benefits of foam retrofits – the ability to air seal. In our experience, these foams can shrink up to 1/2” in every direction and are easily damaged. We do not recommend tri-polymer foams.

Mineral Wool

Mineral wool is made from woven gypsum fibers. It is a good insulator and an excellent fire retarder. There are no petro-chemicals in mineral wool and it can withstand compression. There are many applications where this material can be the right choice.

Cotton Bats

There are several brands of recycled denim bats on the market that are a good substitute for fiberglass. They use recycled cloth as an input, and they have very good sound attenuation properties. They contain the same borate materials as cellulose to improve fire properties and inhibit mold growth.

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