Why Batts and Loose Fill Insulation Won’t Work for an Old AtticFiberglass or cotton insulation batts have been used for years in more modern home designs because of their easy installation and low cost. But this doesn’t apply to most historic homes. Rafters of historic attics were often spaced differently than the industry standard spacing you will find in more modern houses. This makes it difficult to install batting—and more costly if it has to be cut up and fit to unusual spaces. Loose fill fiberglass or cellulose insulation is a little easier to install, but is more expensive than batting. And, neither batting nor loose fill can address air leaks or reinforce the envelope of your attic the way spray foam insulation can.
Types and Applications of Spray Foam InsulationSpray foam is the newest form of insulation used by contractors to provide superior performance in buildings that require a secure envelope for heating and cooling systems. But homeowners are also using spray foam insulation in spaces like attics to expand the conditioned space of their homes for things like extra bedrooms and game rooms, or to provide proper protection for their AC unit and ductwork. Creating an insulated closet in your attic can also provide proper storage for out-of-season clothing that is heat and moisture regulated. It’s ideal in a historic home with architectural constraints that make traditional batts and blow-in insulation difficult to install, as well as ineffective. Spray foam insulation comes in two types, open-cell and closed-cell. These have different R-values based on their densities, and it is recommended that you consult a professional about which one is best suited for your project since there are performance and environmental factors associated with both types. General characteristics of each are:
- Provides sound dampening
- Is inexpensive
- Has an R-Value of 3.7
- Provides a superior air barrier
- Offers structural reinforcement
- Can be used for indoor and outdoor applications
- Has an R-value of 6
1-Part Spray Foams:
- Applied using small cans
- Used to seal gaps in windows
- Used to seal small air leaks common to old attics
2-Part Spray Foams:
- Housed in barrels
- Require that a resin and a compound be mixed together prior to application
- Often used by contractors to seal air leaks and insulate ductwork of historic homes
- Used to insulate attic floors and walls in historic houses
The Advantages of Spray Foam Insulation for Your Historic Home AtticSpray foam insulation is made up of resin and chemical compounds that, when combined, react to form rigid cells. When it is sprayed on a surface, the reaction begins to occur and the foam expands and hardens, filling in and closing up any spaces that might have escaped the application process. This property of expansion is what makes spray foam superior to typical fiberglass and cellulose types of insulation in attics of historic homes that have unusual elements that make them difficult to insulate. Aside from providing superior sealing for air leaks, other advantages of spray foam insulation are:
- Durability: Spray foam insulation has a longer lifespan than most fiberglass and cellulose types.
- Higher R-value: Out of all the insulation types, it has the highest R-value.
- Resistance to mold and moisture: Because it has the ability to eliminate air leaks if installed correctly, no moisture can get through, making it difficult for mold to form.
- Adaptability: Spray foam allows you to insulate all those difficult to access architectural elements of your historic home’s attic.
- Increases frame strength: Unlike other types of insulation, spray foam adheres to surfaces, adding an extra layer to the envelope of your historic attic and reinforcing the strength of the frame—whether it be the floor, wall, or ceiling.
- Soundproofing: In addition to all the other benefits, it helps with soundproofing your home.