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

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Chris Cole Posted: May 10, 2008 10:43 AM	Humidity I am in the early stages of starting a foam business. We have a lot of humid days down here on the gulf coast. How does the humidity play a part in spraying. Is there a cut-off to where I have to say, I cant spray today? Chris
mason Posted: May 10, 2008 02:50 PM	Humidity is important. Most manufacturers do want you spray within 5 degrees of dewpoint, a few are even more strict. Also be sure to check the substrate moisture with a probe. You typically cannot see moisture in wood very well. Be sure to check the framing members, joists and beams. Those are the areas where water likes to accumulate.
Terry Adams Posted: May 12, 2008 01:07 AM	I been spraying down here for 3 years and no problems with humidity. The only problem you will have down here are there are only 2-3 foam jobs a week and 12 local foam guys and at least 6 out of town foamers all try to bid them. Good luck and don't expect to get anywhere near the board foot prices your supplyer is telling you. There are guys spraying closed cell for 60 cents a board foot and open cell for 25 cents a board foot. Suppliers don't care cuz their prices are going up.
mason Posted: May 12, 2008 07:28 AM	Terry, Humidity is important, wood tends to absorb a lot of moisture. I worked on the Gulf Coast for decades and my father before me. Be sure to check out the moisture content of the wood surface before starting. It can be wet outside so long as the inside humidity is ok and the inside substrate relatively dry. (less than 19% moisture content as measured by a moisture probe such as a Delmhorst). You need a surface that is suitable for paint, relatively clean and dry.
David Hanson Posted: May 12, 2008 04:33 PM	What happens to closed cell foam if humidity is too high when it is applied? Does it look different, or does it exhibit different physical characteristics and/or measured performance?

Author

Comments

Chris Cole

Posted: May 10, 2008 10:43 AM

Humidity

I am in the early stages of starting a foam business. We have a lot of humid days down here on the gulf coast. How does the humidity play a part in spraying. Is there a cut-off to where I have to say, I cant spray today?

Chris

mason

Posted: May 10, 2008 02:50 PM

Humidity is important. Most manufacturers do want you spray within 5 degrees of dewpoint, a few are even more strict. Also be sure to check the substrate moisture with a probe. You typically cannot see moisture in wood very well. Be sure to check the framing members, joists and beams. Those are the areas where water likes to accumulate.

Terry Adams

Posted: May 12, 2008 01:07 AM

I been spraying down here for 3 years and no problems with humidity. The only problem you will have down here are there are only 2-3 foam jobs a week and 12 local foam guys and at least 6 out of town foamers all try to bid them. Good luck and don't expect to get anywhere near the board foot prices your supplyer is telling you. There are guys spraying closed cell for 60 cents a board foot and open cell for 25 cents a board foot. Suppliers don't care cuz their prices are going up.

mason

Posted: May 12, 2008 07:28 AM

Terry,

Humidity is important, wood tends to absorb a lot of moisture. I worked on the Gulf Coast for decades and my father before me. Be sure to check out the moisture content of the wood surface before starting. It can be wet outside so long as the inside humidity is ok and the inside substrate relatively dry. (less than 19% moisture content as measured by a moisture probe such as a Delmhorst).

You need a surface that is suitable for paint, relatively clean and dry.

David Hanson

Posted: May 12, 2008 04:33 PM

What happens to closed cell foam if humidity is too high when it is applied? Does it look different, or does it exhibit different physical characteristics and/or measured performance?

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