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Matt Findley Posted: Jan 27, 2011 09:39 PM	close cell dry rotting out plywood I have a building contractor worried about close cell foam sprayed in walls dry rotting the plywood. I told him I dont see how it could. The tyvek lets it breath from the outside. Whats your opinion?
SprayFoamSupply.com Posted: Jan 27, 2011 09:54 PM	Dry rot is caused by a fungus in wood. It is prevented by controlling moisture and keeping the walls dry. Nothing does this better than closed cell foam. I wonder how much moldy fiberglass he has pulled out over the years only to find black, soft plywood behind it. That is what he should be concerned about. See link at left. George
Matt Findley Posted: Jan 27, 2011 10:39 PM	Thanks for the fast reply. You confirmed what I "thought" was the correct information. I just wanted to be sure I was relaying the correct information to my customers. Thanks again.
mason Posted: Jan 28, 2011 07:46 AM	Good information George. However, be sure wood is not saturated with water and is free of little critters such as termites or carpenter ants. If the wood has a lot of moisture in it already, the addition of closed cell foam will increase the amount of time it takes to dry it out. Meanwhile if there is already insects in the wood or deteriation starting, this would tend to make the situation worse. So just make sure you check the moisture content of the wood before spraying the foam . However, once the foam is in place (properly installed), it will reduce the potential for condensation, thereby reducing the potential for wood rot.

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Comments

Matt Findley

Posted: Jan 27, 2011 09:39 PM

close cell dry rotting out plywood

I have a building contractor worried about close cell foam sprayed in walls dry rotting the plywood. I told him I dont see how it could. The tyvek lets it breath from the outside. Whats your opinion?

SprayFoamSupply.com

Posted: Jan 27, 2011 09:54 PM

Dry rot is caused by a fungus in wood. It is prevented by controlling moisture and keeping the walls dry. Nothing does this better than closed cell foam. I wonder how much moldy fiberglass he has pulled out over the years only to find black, soft plywood behind it. That is what he should be concerned about. See link at left.

George

Matt Findley

Posted: Jan 27, 2011 10:39 PM

Thanks for the fast reply. You confirmed what I "thought" was the correct information. I just wanted to be sure I was relaying the correct information to my customers.
Thanks again.

mason

Posted: Jan 28, 2011 07:46 AM

Good information George. However, be sure wood is not saturated with water and is free of little critters such as termites or carpenter ants.

If the wood has a lot of moisture in it already, the addition of closed cell foam will increase the amount of time it takes to dry it out.

Meanwhile if there is already insects in the wood or deteriation starting, this would tend to make the situation worse.

So just make sure you check the moisture content of the wood before spraying the foam .

However, once the foam is in place (properly installed), it will reduce the potential for condensation, thereby reducing the potential for wood rot.

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