cedar shakes | Ask Mason Knowles - SPF Consultant | Spray Foam Technical Questions and Answers | SprayFoam Magazine Q&A Forums

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Posted: Apr 24, 2008 01:57 PM	cedar shakes Hi Mason, I'm bidding a job that is using white cedar shakes for the roof. In some spots they used plywood sheathing with no cedar breather and some roof bays end at a header. I've used styro baffles before to give air supply from soffit to ridge vent but can't use here. Talked to shake manufacturer and rep said he sees no problem applying cc to underside of shakes. I see a large liability issue here. Thoughts? OC?
mason Posted: Apr 25, 2008 09:11 AM	This is one of the situations where your caution is warranted. SPFA's Technical Committee does not recommend installing SPF directly to cedar shakes. Moisture and movement can negatively affect your foam application. Check SPFA technical document AY 112 for backup at sprayfoam.org

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Posted: Apr 24, 2008 01:57 PM

cedar shakes

Hi Mason,

I'm bidding a job that is using white cedar shakes for the roof. In some spots they used plywood sheathing with no cedar breather and some roof bays end at a header. I've used styro baffles before to give air supply from soffit to ridge vent but can't use here. Talked to shake manufacturer and rep said he sees no problem applying cc to underside of shakes. I see a large liability issue here. Thoughts? OC?

mason

Posted: Apr 25, 2008 09:11 AM

This is one of the situations where your caution is warranted. SPFA's Technical Committee does not recommend installing SPF directly to cedar shakes. Moisture and movement can negatively affect your foam application.

Check SPFA technical document AY 112 for backup at sprayfoam.org

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