Spray Foam Under Rafters

A-1 Insulation foam can be applied to the underside of rafters in a roof. This reduces conduction through the roof, lowers attic temperatures and blocks radiation. However it can also raise the attic floor temperature and potentially damage the roof materials in some climates. This can be addressed by using a hybrid application that ventilates the attic floor through baffles on the side or ridge vents up top.

The biggest pro to insulating the underside of rafters is that it creates a conditioned space in your attic and keeps the internal weather out of the rest of your home. However, this does cut off the attic from the rest of your house and can experience vast temperature swings during the seasons depending on the weather outside. This can cause problems with moisture and air infiltration if the attic is not properly vented.

Spray Foam Under Rafters: Benefits and Considerations

If you choose to go this route be sure to hire a company with experience and the right tools. You’ll need to use a depth gauge to ensure you are installing the correct thickness of foam and coating. The thickness is important because it determines the R-value you want to achieve and how well your roof slopes. If the roof is not sloped properly it can result in ponding or standing water on your roof. This can also result in a manufacturer’s warranty being denied.

“A-1 Insulation
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“Greer, SC, 29651
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864-506-4098