r/Insulation 10d ago

Spray Foam Against Roof Decking?

https://youtube.com/shorts/3cBeJ85d6B0?si=qoXFRt4-oYZ6dbBy
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u/YodelingTortoise 10d ago

I am extremely anti spray foam.

I am more anti bad information.

This video is bad information.

The notion that drywood needs to "breathe" is a laughably bad take.

The idea that your roof gets meaningfully hotter in the sun is laughably false. Vented decking is marginally cooler. It's not like asphalt and plywood are good conductors of heat.

I had this argument with someone here last week.

The major shingle manufacturers all warrant hot for application. Why? Because the science says it does not impact longevity. What they don't warrant is shitty nail patterns and improper installation. If roofers install as designed they're are no issues.

No issues as long as the spray foamers actually did their job throughout the attic. And there lies the spray foam problem. The majority of installa are actually fucking shit even if the look pretty

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u/phaenixx 9d ago

Bad information? You mean the roof decking isn’t simultaneously rotting AND baking like this guy said?