Say the word "insulation" and chances are you envision yourself wrestling with a huge roll of fiberglass insulation or paying a professional to blow shredded newspaper around. Spray foam insulation offers a compelling alternative to traditional fiberglass and cellulose insulation. The following explains the benefits of spray foam insulation, as well as its caveats and how it fares against other types of insulation.
Why Use Spray Foam?
One major advantage of spray foam is that it offers a very effective barrier against cold and heat. As the foam is sprayed in, air becomes trapped within the individual cells, forming an air barrier that resists extreme temperature changes. As another advantage, spray foam quickly expands as it's applied, allowing it to spread into and seal off various nooks and crannies for the highest possible insulation value.
Even as it hardens, spray foam insulation remains flexible enough to cope with building stresses without losing its insulation value. This makes spray foam insulation an excellent long-term investment for most homes and businesses.
Open-Cell vs. Closed-Cell
There are two main types of spray foam insulation to choose from – open-cell and closed-cell. Each type has its own set of advantages and disadvantages to consider:
- Open-cell spray foam insulation features a lower R-value (3.5 to 3.6 per inch) and its relatively low density makes it more susceptible to vapor permeation, especially when used in cold climates to insulate unconditioned spaces. On the other hand, it's cheaper than closed-cell foam (at $1 per square feet) and it can be protected with either vapor-retarding paint or a vapor barrier.
- Closed-cell spray foam is more expensive than its open-cell counterpart (at $1.75 to $3 per square feet), but it offers a higher R-value (6.5 per inch) and, due to its closed-cell nature, has a greater imperviousness to moisture than open-cell foam. Closed-cell spray foam also has significant adhesion properties, allowing it to be used to structurally fortify walls and ceilings.
The type of spray foam insulation you choose will depend on your home's specific insulation needs as well as your budget. It's usually a good idea to have a home energy audit performed prior to choosing your insulation.
Is It Safe to Use?
It depends on which type of spray foam you use. Open-cell spray foams rely on water or carbon dioxide as a blowing agent, making it the environmentally friendly choice if you're looking to insulate your home while staying as green as possible. Some varieties of open-cell spray foam insulation are also made of soybean oils and other natural materials, as opposed to the typical petrochemicals used to manufacture spray foams.
On the other hand, most closed cell spray foams rely on hydrofluorocarbons (HFCs) as the blowing agent. Designed to replace chlorofluorocarbons (CFCs), HFCs are well known for contributing to the "greenhouse effect" despite having a negligible effect on the ozone layer.
There's also a potential for spray foams to emit potentially toxic chemicals if they're not mixed correctly during the spraying process. However, most professionals are well trained when it comes to applying spray foams and a proper application won't have any of these problems.
Comparisons to Other Types of Insulation
When compared to other types of insulation, spray foam usually outperforms its counterparts by a significant degree. It can fill in crevices and corners better than fiberglass or cellulose and it's not prone to sagging or settling over time.
On the other hand, traditional fiberglass and cellulose insulation is usually cheaper to install than open-cell or closed-cell spray foam insulation. If you're looking to insulate your home on a budget, then you may want to consider these other varieties of insulation. However, keep in mind that the long-term savings offered by spray foam insulation may offset its up-front costs.