Can I Install a Metal Roof Over Shingles?
LESLIE: We’re heading over to North Carolina where Nicole has a roofing question. Tell us what’s going on.
NICOLE: Well, we had a tree fall on our house and we had no structural damage but we had shingle damage. And so we’ve been working on finding the best reroofing option. So we’ve gotten some estimates and been looking around and researching; doing some research on the different types of shingles and that sort of thing.
And what we’d really like to do is to go for a metal roof and we have a bid that’s not completely outrageous, which is nice. But the question, I guess, that we have is we’ve been told that some people choose to leave the shingles on the roof and to put the new, metal roof on top of it. Some people have said that it – that that minimizes the lifetime of the roof; of the new roof. So we’re just calling to get your take on that.
TOM: OK. I think what you’re doing is you may be confusing multiple layers of asphalt shingle roofs with a layer of asphalt under metal. First of all, I don’t think it will shorten the lifetime. If you’re talking about multiple layers of asphalt shingle roof, yes, a second layer is not going to last as long as just a single layer, because the single layer acts as a heat sink and stores a lot of heat.
And frankly, it’ll do some of the same thing with a metal roof and it’ll radiate some of that heat back into your house. But the nice thing about metal roofs is that they have – and you should confirm this with the product you’re thinking about buying – but most of them have low-e paint on them. So, essentially, they radiate a lot of the heat; they sort of bounce it right back out.
Now that said, I would prefer, if you’re putting a metal roof on, to make sure it was on the structure and not on a previous layer of roof. I don’t think it should add dramatically to the cost to take off that initial layer and I just think it’s a much nicer, cleaner way to do a metal roof. I mean a metal roof can last you a lifetime, so why have a …?
LESLIE: Yep. Fifty-plus years.
TOM: Yeah, why have a second layer of roofing underneath that for all that time?
NICOLE: Yeah, we’ve also been cautioned about how the metal lays because if it’s not put on …
TOM: Right, exactly. Yeah and so let’s say that you – let’s say that that roof starts to buckle a bit or those shingles start to curl underneath the metal roof, it could raise up the space. So I would tell you, if it was me, I’d probably pull it off even though I didn’t have to.
LESLIE: Mm-hmm. And Nicole, you may want to check with your community because I know in some municipalities, when you go to get your building permits, you know, some of them require a certain type of paperwork if you are leaving the roof structure as is and just putting a new layer on top and some require a different type of permitting if you’re taking everything off. So just make sure you follow up with your community, so you’ve got everything filed before you start the process.
NICOLE: Perfect. Thank you.
TOM: You’re very welcome. Thanks so much for calling us at 1-888-MONEY-PIT.