So, You Want to Insulate Your Home: Choosing the best Insulation Material (Part 2)
There are four common types of insulation that are typically used in homes
- Spray Foam
- Rigid Foam Board
With so many different options and methods to insulate your home, it may be difficult to determine what material is the best to use in your home, meets what you are trying to achieve, and gives you the best value for your investment. To make this decision it is important to understand what materials can be used in which areas of your home and the benefits each offer.
Spray Foam Insulation
Spray foam insulation can be used in two different applications, open cell and closed cell. Open-cell spray foam is less dense than closed cell, giving it a spongier feel. It contains more air pockets, therefore, lowering its R-value per inch and reducing its ability to resist moisture. Closed cell spray foam, is far more dense than open cell and acts as both a moisture and air barrier. Due to the density of both open and closed cell spray foam, and its expanding capabilities, it fills cracks and crevices that Fiber Glass and Cellulose do not, and offers air sealing properties.
Spray foam can be used in many applications such as:
- Crawl Space & Foundation Walls
- Crawl Space Joists
- Attic Rafters
- Attic Knee Walls
- Wall cavities
- Metal buildings
Spray foam has the unique quality of adhering to just about anything, so it is extremely diverse in application.
If you choose to insulate your crawl space with spray foam you will likely either insulate your crawl space walls or between the floor joists. It is typically recommended to use closed cell spray foam in order to create both a moisture and thermal barrier instead of using the more porous open-celled spray foam which does not resist moisture. It is important to remember that when using closed cell spray foam to resist moisture, it is considered a class 2 vapor retarder only when applied at approximately 1.5” or more. If you have HVAC equipment or ductwork in your crawl space, insulating from the crawl walls and dropping your thermal barrier to the ground means you are controlling the environment your HVAC equipment and duct work lives in which can result in less wear and tear on your HVAC unit and a more comfortable home for you.
The use of spray foam insulation in the attic is typically recommended to insulate from the attic rafters. By doing so, this moves the thermal barrier of your home from the attic floor to the attic rafters. This is also a good option if homeowners plan on finishing their attic after insulating or have HVAC equipment in their attic. By moving the thermal barrier, the HVAC is not inside and not subject to external factors. This means the unit can run more efficiently and less often. In this application, you can use either open or closed cell spray foam, depending on what you want to achieve.