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Spraying to steel substrates Post New Topic | Post Reply
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Robert Webster
Posted: Mar 11, 2008 12:39 AM
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Spraying to steel substrates
Looked at a pole barn the other day that another guy sprayed with opencell foam. The walls had 1-3 1/2" of oc, some sprayed directly to the exterior steel, and some to tyvek that had been put on a back wall(between the steel and the poles). The underside of the roof had been sprayed with about 2-3"s of oc all directly to the steel. Owner was upset, a fair amount of the oc on the walls was sprayed off ratio(or something)it would just rub off. Then in the areas that looked and felt good the owner had cut a hole to add a utility line in and noticed water running out the hole. Same in the ceiling he cut a 3"hole in roof and water ran out from uabove the foam. Everywhere he penetrated the foam it was very wet(saturated), and the backside of ext steel is heavily condensated(both areas with and without tyvek)between steel and foam. Thoughts??? and Input??? |
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SprayFoamSupply.com
Posted: Mar 11, 2008 07:03 AM
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Are you in a cold climate? Open cell foam allows some moisture to pass through it. Sounds like moisture could be condensating on the cold steel. Is the foam that just rubs off all dry and brittle? Maybe A rich? Anything off ratio should be ripped out, substrate cleaned and resprayed. If there is condensation everywhere, once the off ratio foam is fixed, you could wait till summer and see if the foam dries out. If it does, you could spray over the foam with a vapor retardant paint. That may or maynot fix the problem. The best solution would be to remove all of the foam, prep the substrate, and respray with 2" of closed cell. Surely that will fix the problem. George Disclaimer: This is only my opinion from a 30 second description of a problem posted on some message board. Opinions can change over time as spraying foam is a continuing education. I certainly don't want to be accused of "giving out alot of mis-information on this site". |
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David Kang
Posted: Mar 11, 2008 06:15 PM
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If properly applied, nione of these problems should occur. The powdery substance is an indicator of densification, usually a sign of cold substrate. My bet from the 30 second take is that the foam was applied to a cold substrate, causing sepersation. Outside cold, inside warm...condensate occurs. I almost agree totally with George!! I don't agree the 2# is an automatic fix...., and I woujld not use the vapor retardant paint unless the adhesion problem is fixed first. |
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David Kang
Posted: Mar 11, 2008 06:15 PM
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If properly applied, nione of these problems should occur. The powdery substance is an indicator of densification, usually a sign of cold substrate. My bet from the 30 second take is that the foam was applied to a cold substrate, causing sepersation. Outside cold, inside warm...condensate occurs. I almost agree totally with George!! I don't agree the 2# is an automatic fix...., and I woujld not use the vapor retardant paint unless the adhesion problem is fixed first. |
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Robert Webster
Posted: Mar 13, 2008 12:05 PM
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The building is in a cold climate was sprayed at 45degrees according to owner, and foam isn't powdery its got spots that are soft as cotton and smear off. Definately heavy condensation betweeen steel and insulation (however most of oc is bonded to steel(99%), and yet there is heavy condensation there and the 1st 1/2" of foam is saturated (roof and walls). Will that moisture eventually dry up so he can cover with a vapor retardent(perhaps cc), or does he need to remove the foam to prevent corrosion of the steel over time? was his question. Interested in everyones input on subject....Thanks |
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Robert Webster
Posted: Mar 16, 2008 01:56 PM
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