Water based foam

Geo-TH,In · Oct 5, 2019

Planning on using spray foam on metal roof as a moisture barrier.
Insulator is concerned about urathane foan sticking to condensation.
Pole barn is 8 weeks out. So looking at sometime in Novermber.

Nephew tells me there is a water based foam that sucks up water.
Has anyone used it on inside of roof for moisture barrier? Pros and Cons please.

TJV · Oct 5, 2019

Not sure what kind of foam was used, our neighbor spray foamed his shop roof and walls in the beginning of December (in Minnesota) with no problems the only stipulation was it couldn't be too cold outside.

tomturkey · Oct 5, 2019

It may have to be done on a warmer day when the sun is shining on the roof. Even in the winter my uninsulated pole barn roof creaks and groans as the sun hits it and it expands. A bit of sun and open doors for air flow, there will be no condensation. jmho gobble

zep · Oct 5, 2019

I used to spray both types of foam on the north slope in Alaska. The main difference in the foam and the water soaking problem is open and closed cell types of foam.I would say you want the closed cell which would be urathane foam.Hope this helps.Tim

Adirondack case guy · Oct 5, 2019

Zep; I have a question for you. When I was erecting commercial steel buildings the insulation company that did our insulation work said that open cell was necessary on exterior steel because the steel expanded and contracted with heat and cooling and exposure to direct sun light. The open cell would expand and contract with this issue, and closed cell would not and lead to coming loose or distortion of the sheet steels. What is your take on this reasoning?? They also insisted on an air gap between the foam and the 2" thick DOW INSOLBOARD that we applied to the interior for walls and ceilings. which had a 1 hr. fire rating and offered another R-10 insulation rating, and was a moisture barrier.
Loren

Geo-TH,In · Oct 5, 2019

Loren,
Thanks for post. I didn't know about open cell. I'll have to shop around.

A guy who likes to cut my trees for the fire wood works for an insulated company. He's a union insulator. I'll have to give him a call.

dcarp · Oct 5, 2019

Our house, which is all metal on the outside, is insulated with the open cell foam. We used a moisture barrier like Tyvek under the metal and then sprayed the foam on. The Tyvek or a similar product is inexpensive. Any condensation will stay on top of it and run off. We have lived here 5 years now, no problems with the foam.

JD Seller · Oct 5, 2019

All I can say is both of my shop ceilings and four machine sheds have closed cell foam on the roofs. The oldest is right at 20 years old now. None of them given any problems.

George rather than taking what guys on here say, go to some local people that have had it done in YOUR area by companies that are the ones you would be getting to do yours.

PJH · Oct 5, 2019

Pick up the phone and call the people who make the metal. They'll tell you exactly what to use. They want your metal roof to be a success even more than you do.

Geo-TH,In · Oct 5, 2019

I will go to a business and insulation is their only business. Also got quotes from insulation businesses. Didn't ask if they use open or closed.

Bob Harvey · Oct 5, 2019

George, use 'house wrap' or 'Tyvek' under the metal. Whatever you use under that for insulation needs at least 2" of airspace from the soffit to the ridge - use ridge vents. I have done LOTS of these installations and it works. Anything else will 'sweat', mess up any insulation , and cause problems. Take my advice or don't - don't care, your choice.

Water based foam

Geo-TH,In

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TJV

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tomturkey

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zep

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Adirondack case guy

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Geo-TH,In

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dcarp

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JD Seller

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PJH

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Geo-TH,In

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Bob Harvey

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