Use of Spray-Foam Insulation for Cold Climate
LESLIE: Ron in Alaska is on the line and needs some help with the use of spray-foam insulation. What can we do for you today?
RON: Well, I’ve got a house that was pretty extensively remodeled and all polyurethane spray-foam insulation.
RON: And we went in – yeah, that’s what I thought. Well, we went into the first winter season – about into about 10-degree Fahrenheit weather – I notice a lot of frost buildup in various areas in my eaves. And as I looked closer, the more I find. And then we come out of the cold – well, it kind of cycles through about, I don’t know, a period when we come into some warmer weather and I’ve got water leaks around various areas, down the side of the house and everything.
So then I start taking a ladder and going up and I’ve got what I would call a “hut (ph).” So I’ve got tongue-and-groove – it’s (inaudible) and they put 2×12 rafters with OSB on top and then the shingles. And in between the rafters, they put the spray-foam urethane. Well, I can look up, because I don’t have my soffits closed in yet. I can look up with a bright light up in there and I see balls of ice on the bottom of the OSB, so it’s – you know, basically, what’s happening is we’ve got a lot of little air leaks where hot, humid air from inside the house is venting out and then it condensates, I guess, and freezes.
TOM: You know what’s interesting about this story is it sounds to me like the use of spray-foam insulation was not done correctly. Because when you use of spray-foam insulation, you convert your attic from a non-conditioned space to a conditioned space. It more becomes part of the living space than the exterior space. And when you use spray-foam insulation, you typically do not need ventilation. In fact, sometimes, the best thing to do is to seal off the old ventilation because spray-foam insulation, again, when properly installed, does not need to be vented.
Now, you said you put this up between the rafters. Did it cover the rafters or was it just sort of covering the sheathing?
RON: Well, the rafters go all the – because it is vented. So the rafters go all the way up to the OSB.
TOM: Of course. But the thickness of the foam insulation, did it actually cover the rafters when it was applied?
RON: No, they put in 12-inch-high rafters and they only went with 8 inches of foam so there’d be 4 inches of venting.
TOM: I see. If you don’t mind me asking, what brand insulation did you put in here?
RON: Ooh, I don’t know. I know the company I used but I don’t know what brand they used.
TOM: I think you need to reach out to the manufacturer and send some photos, because I suspect the use of spray-foam insulation was not done well. When you do foam insulation, you don’t have to vent that space. And the fact that it is vented now means that you’re going to have the same kinds of condensation issues that you had before but maybe even potentially a little bit worse. So I suspect it was an issue with the installation.
This should not be happening. I personally have a spray-foam – converted spray-foam – attic where I have a very old house from the 1800s. And when the guys I hired put this in, they completely covered the rafters. And that space always amazes me, especially when it’s very cold or very hot outside, because when I go up there it’s the same temperature as the rest of the house. We knew we’d lose no heat out of the attic. But there’s no ventilation. Where there was a vent, we have a window and we never had soffits.
RON: Yeah, so I see what you’re saying. You applied more of a complete blanket across the whole roof, where I’ve got breaks. Every time there’s a rafter, there’s a break.
RON: So they’ve done it in rows.
TOM: Mm-hmm. Yeah.
RON: Ah, very interesting. And I bet you that – I bet you you’re on to something there because that’s – I’ve thought about every little angle other than that.
TOM: Yeah. So here’s the thing. I mean if you go back to your contractor, they’re probably going to have a bunch of excuses at this point. I would take photographs. I would figure out who the manufacturer is. I would contact their technical-services department and say, “Here’s my situation. Can you help me out? Tell me what’s going on. And how do I fix it?” And they’re probably going to point at the installation as the cause but they’ll tell you exactly what’s going on. And then, once you have that, then maybe you can go back to the contractor and say, “Look, you guys made a mistake here and here’s how – here’s what has to happen.” And at least you won’t waste any time being baffled by any potential contractor BS, if you know what I mean.
RON: Yeah. And that’s what I’m getting. And I’ve got $36,000 into this roof and there’s no access. It’s demolition to get to any of this area (inaudible).
TOM: Yeah, well, that’s why I say you need to get the right information here to know if the spray-foam was properly applied. And if you can’t get it from the manufacturer, then I would hire my own expert. I would find a good-quality professional home inspector or an engineer to evaluate that project, compare it against the specs and write a report determining what’s happening and what has to be done to fix it, OK?
RON: Alright. Good help. One quick, last question: do you – what type of engineer would I look for? Just a mechanical engineer?
TOM: No, probably a structural engineer.
RON: OK. OK.
TOM: Yeah. Or a home inspector. You can go to ASHI.org – A-S-H-I – the American Society of Home Inspectors – .org. And actually, I think it’s HomeInspector.org. Let me correct myself. And you could find an ASHI-certified member in your area. You’ll probably get a list of two or three or four by ZIP code and I would talk to each one, tell them what’s going on and find out who’s going to be the most competent to come out and evaluate it and write a report about it.
RON: OK. Very helpful. Very much appreciated.