Should a Metal Roof be Installed over Asphalt?
LESLIE: Tony in Georgia is on the line with a roofing question. How can we help you today?
TONY: I wanted to transfer from a shingle roof to a metal roof. And I wanted to know if leaving the shingles on would give me a better insulating factor and if there are any other pros or cons that you could advise me on.
TOM: Well, leaving the shingles on gives you zero insulating factor. What it can do is add to the inefficiency of your home’s insulation system, because it’ll act as a heat sink. It’ll hold a lot more heat in that roof structure and that will raise the temperature of the building, costing you, ultimately, more air conditioning.
It also can result in the roofing material – the metal roofing material – be appearing uneven. So I would strongly encourage you to strip off all of those shingles. Metal roofing is a big investment. Let’s do it once, do it right and you won’t have to do it again for a hundred years. So it’s definitely worth stripping it off and starting from scratch.
TONY: Yeah. Also, I noticed that it is much better – easier – to walk on than it would be if it was just lap boards with metal on top of it.
TOM: I can see that but you shouldn’t really have to do much walking on that roof once it’s done.
TONY: Yeah, yeah. Once it’s done, it should last my lifetime.
TONY: Well, I appreciate your advice on this.
TOM: Well, you’re welcome. Good luck with that project. I think you’re doing a good thing, 888-666-3974.