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Yvan Richard Posted: Feb 27, 2011 09:10 PM	Moisture Hello, I have a customer claiming that he is getting moisture between the spray foam and rim joist. We sprayed when it was dry, the substrate was approx. 10 celcius, so no issues there. Could there be gap between the top of the concrete basement wall and the plate? There was also a few days of snow melting outside, perhaps the spf simply could not hold back the moisture? Do you have an idea of of what some of my options are to fix this? How well can spf hold back water coming into a leaky basement? From my understanding eventually the foam will become saturated and begin to fail and not have an opportunity to ever dry out. Thank you.
mason Posted: Feb 28, 2011 07:25 AM	Closed cell foam will hold back bulk water but if there is a vapor drive going into the foam, it can become saturated. (unless there is a very high water table and a lot of hydrostatic pressure forces water into the foam). The foam can only stop water where it is sprayed. If there are gaps or cracks above where the foam is sprayed, then yes, water can get into the space. First you have to find out where the water is coming from, cracks in the wood framing, from the foundation wall or somewhere else. You may need to provide waterproofing and/or flashing from the outside to stop the infiltation of water into the space. You might also be having a vapor drive problem, if the foam is not sprayed in sufficient thickness to stop condensation. If the problem evident in the winter months and not in summer then that could be the problem. A hygrothermal modeling study would help determine the correct thickness of foam to use. In northern climates this would be between 2-3 inches of closed cell foam.

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Comments

Yvan Richard

Posted: Feb 27, 2011 09:10 PM

Moisture

Hello,

I have a customer claiming that he is getting moisture between the spray foam and rim joist. We sprayed when it was dry, the substrate was approx. 10 celcius, so no issues there. Could there be gap between the top of the concrete basement wall and the plate? There was also a few days of snow melting outside, perhaps the spf simply could not hold back the moisture?
Do you have an idea of of what some of my options are to fix this?

How well can spf hold back water coming into a leaky basement? From my understanding eventually the foam will become saturated and begin to fail and not have an opportunity to ever dry out.

Thank you.

mason

Posted: Feb 28, 2011 07:25 AM

Closed cell foam will hold back bulk water but if there is a vapor drive going into the foam, it can become saturated. (unless there is a very high water table and a lot of hydrostatic pressure forces water into the foam).

The foam can only stop water where it is sprayed. If there are gaps or cracks above where the foam is sprayed, then yes, water can get into the space.

First you have to find out where the water is coming from, cracks in the wood framing, from the foundation wall or somewhere else.

You may need to provide waterproofing and/or flashing from the outside to stop the infiltation of water into the space.

You might also be having a vapor drive problem, if the foam is not sprayed in sufficient thickness to stop condensation. If the problem evident in the winter months and not in summer then that could be the problem. A hygrothermal modeling study would help determine the correct thickness of foam to use. In northern climates this would be between 2-3 inches of closed cell foam.

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