Install a Metal Roof Over Asphalt Shingles
LESLIE: Next up, we’re going to take a call from Frank in Alabama who has a shingling question.
Frank, what can we do for you?
FRANK: Yes, I have a question regarding roofing.
LESLIE: Roofing. Excellent.
FRANK: Metal roofing has gotten to be very popular in the southeast and I am wondering – I’ve seen it done two ways: with the conventional shingles ripped off and the metal roofing applied; and in some forms, stripping put down over the shingles and the metal roofing applied on top.
LESLIE: Well, what type of roofing shingles do you have now?
FRANK: Right now, fiberglass shingles.
LESLIE: Fiberglass. And have you been in the house a long time?
FRANK: Quite a while.
LESLIE: Are you planning on staying there?
TOM: Well, I’ll tell you. If that’s the case, you’re probably better off removing all of the shingles because you’re going to get the better job in the long term if you start clean with just your roof sheathing, Frank. If you try to go on top of that, if there’s any deflection in those roof shingles from built-up layers over the years, that can show up through the metal. Plus it makes it really hard if you ever want to make a modification to that: fix a leak, put in a skylight, run a plumbing pipe through it, or anything of that nature. It’s just that much more material to do. So if you’re thinking about replacing your roof now, I would suggest that you rip off all of the shingles.
And I would give you the same advice regardless of whether or not you’re putting on an asphalt roof or a metal roof. If you’re putting on another asphalt roof, the advice is even more important, though, because if you have old roofing layers underneath the new roofing layer, the new roof is not going to last nearly as long as the old roof.
LESLIE: Because the old roof will actually cook – they’ll heat up and they’ll cook the new shingles, right?
TOM: Exactly, and you’ll be serving cooked shingles. You’ll lose about a third of your roof life that way. OK, Frank?
FRANK: Thanks a lot.
TOM: You’re very welcome. Thanks so much for calling us at 1-888-MONEY-PIT, 888-666-3974.
It’s really an economic question, isn’t it, Leslie?
LESLIE: Well, you know, it’s also a time question. Do you have the time to remove it? Do you want to? And a good thing to know is does it reduce the life of your new roof because why do you want to do all that work only to have to do it again in a short time.
TOM: Exactly. But if you were not planning on staying in the house for a long time, then you might just do it and just enjoy it for, say, five years and leave it for the next owner to deal with.
LESLIE: (chuckles) Tricky, tricky, Tom.
TOM: It’s an economic question.
Frank, thanks again for calling us at 1-888-MONEY-PIT, 888-666-3974. The website, don’t forget, is MoneyPit.com.