# Hybrid Spray/Rigid Foam Insulation



## Windows on Wash (Aug 30, 2011)

Using spray foam between the studs is probably overkill if you are going with a rigid foam topper.

Use a good fiberglass batt, cover it with rigid foam, and then check code and make sure the foam is approved for exposure use. If not, you will need to cover it with an ignition barrier.

Make sure you have enough foam depth to prevent condensation on the framing and/or be careful to make sure you vapor retarder details are correct.


----------



## yaemish (Jun 14, 2010)

Right now I have fiberglass that is exposed and subject to wind washing. I feel like the stuff is next to useless in this type of installation. I would just like to know from someone with experience if this is something that will work effectively.


----------



## Windows on Wash (Aug 30, 2011)

Covering the FG with a rigid foam or other air barrier will prevent the wind degradation of the R-Value.

CC foam definitely has a higher R-Value than FG but comes at a price. If you are using rigid foam, fill the bays with FG or other more batt type insulation, seal all the seams in the rigid and be done with it.

Make sure the rigid foam is covered with the code required ignition barrier or get approval.


----------



## Gary in WA (Mar 11, 2009)

F.g. is good: http://www.finehomebuilding.com/PDF/Free/021105092.pdf

You have to maintain that air barrier: http://oikos.com/esb/51/sideattics.html
http://www.familyhandyman.com/DIY-P...ency/how-to-seal-attic-air-leaks/Step-By-Step

Gary


----------

