When it comes to insulation, aerosol foam is one of the most effective materials available. It provides excellent thermal performance and the highest R-value (a measure of thermal resistance) per inch for greater potential energy savings compared to other forms of insulation of comparable thickness. The higher the R-value, the greater the insulating properties of the material. Spray foam insulation is a great product and homes insulated with it can be some of the most efficient and comfortable homes ever built.
However, spray foam insulation isn't without its problems. Air is a good heat insulator, but you can transfer it by convection. These airbags alone aren't the reason spray foam is so effective. Aerosol foam is effective because of the thin walls between each air bubble, making convection difficult.
This material allows heat to be trapped in air bubbles and no longer escapes. Aerosol foam comes in two flavors, open-cell and closed-cell, and provides the two parts of the building envelope: insulation and air barrier. As spray foam is both an insulator and an air barrier, proper alignment of the insulation and the air barrier is guaranteed. It's a more practical alternative to mineral wool insulation, as it doesn't require walls to be completely open and is more affordable than spray foam. I understand that people need recommendations and do their homework every time they look for a spray foam contractor. I once got a call to see a 10,000-square-foot house that had spray foam everywhere, but the owners had a serious problem their first summer in the house.
We have a 1950s ranch in Atlanta and are interviewing foam contractors to spray an open cell under the roof, with an “ankle” wall facing the eaves to seal the attic. The expandable foam was poured into the crevices and onto the materials, which, in vertical applications, was complicated. The foam manager said it needed ventilation, so completely sealing the attic wouldn't be a good idea. The third sprayer, from another company, was also furious because the company that had built my attic had not vacuumed up all the old cellulose insulation. In addition, he noticed that there were areas where the foam was shrinking or peeling off, and not even five weeks had passed since the spray. Also, they never told me to leave my house for a long time, so I (and my pets) were in the house the day they sprayed and all the time the disproportionate foam filled my house with horrendous vapors. One of these low-GWP options could be a better choice for homeowners who decide that spray foam insulation is right for their home.
My builder used closed-cell foam applied with a thickness of about 1 inch and then used insulation blown to the bottom of the rock sheet. Because closed-cell foam has a higher R-value per inch, installers typically spray 2 inches on walls and 3 inches on ceilings to meet energy code requirements of R-13 and R-19 respectively. In conclusion, aerosol foam insulation provides excellent thermal performance and energy savings compared to other forms of insulation. It's also more practical than mineral wool insulation as it doesn't require walls to be completely open and is more affordable than spray foam. However, it's important to do your homework when looking for a spray foam contractor as there are potential problems that can arise if not installed correctly.
