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Bubbling exterior paint caused by insulation?

I had my old 1900's farmhouse exterior painted in July. The old layers of paint were almost completely removed. I december I had the house insulated, using a product that is blown in air/concrete mix (used on one of the TOH episodes, supposed to be less toxic than other blown in insulations). About a month after the insulation was installed, I noticed the exterior paint had started to bubble. Now it seems that the nearly the entire surface of the house is bubbling up...looks a little like a sharpee dog, drooping down. Any ideas? Was it the insulation?, a bad paint job?

Re: Bubbling exterior paint caused by insulation?


I am not sure of all the dynamics that are going on in your walls, but you can bet your bottom dollar that moisture is involved and those bubbles are caused by vapor pressure.

I am not familar with the type of insulation you describe, not having seen that episode of TOH. I am always hesitant to be the first to try some new miracle product ( remember urea-formaldihide foam of a couple decades ago).

One thng about old farmhouses, the walls had plenty of air moving in them and plenty of places for moisture to exit short of to the outside via pushing off the siding paint.

I suspect that the new insulation in interferring with alternate areas for moisture to exit. Just a guess.

What kind of paint and brand did you use? Full primer, acrylic or oil? What climate are you in?

Re: Bubbling exterior paint caused by insulation?

Ordjen's First and last sentence covers it.
My bet is an Elastromeric coating was used ?

Re: Bubbling exterior paint caused by insulation?

Not sure what this product was that you used for insulation, but it may have had some chemicals in it that had to "off gas" to cure and that gas could have been something that removes paint. So it is possible that once cured, the insulation won't damage the paint anymore, but it could be the cause of the damage now.

Was this insulation blown in through holes was was the interior surface removed and the wall cavity insulated and then new sheetrock put up. If it was the latter, was a vapor barrier installed?

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