beppington
Elite Member
I've installed metal roofing on barns 3 times, but never on a house, which is what I'm interested in doing now. My shingles are going on 20 years old, so I'd want to metal roof over them, if possible. I'd like to use the regular ol' galvanized silver 3'-wide 5-ridge metal roofing available at Home Depot/ Lowes.
The house across from me just did the same, but I believe I saw (from the road) that the roofing company just tar papered over the old shingles, laid the metal roofing right on that, & screwed it down ... I expected to see them install a series of 1x4's over the old shingles first, & then lay the metal roofing on those & screw into them.
With the metal I've used on barns, it's thin enough that I think laying it directly on shingles would let the wavy-ness of the shingles would make the flats of the metal also wavy. Laying the metal on tar paper over top of the shingles might help eliminate that, but I'm not sure.
I also wonder if laying the metal right on the tar paper, like I think they did, would trap moisture between the two & eventually cause the metal to rust underneath?
What do you think? Which way should it be done?
The house across from me just did the same, but I believe I saw (from the road) that the roofing company just tar papered over the old shingles, laid the metal roofing right on that, & screwed it down ... I expected to see them install a series of 1x4's over the old shingles first, & then lay the metal roofing on those & screw into them.
With the metal I've used on barns, it's thin enough that I think laying it directly on shingles would let the wavy-ness of the shingles would make the flats of the metal also wavy. Laying the metal on tar paper over top of the shingles might help eliminate that, but I'm not sure.
I also wonder if laying the metal right on the tar paper, like I think they did, would trap moisture between the two & eventually cause the metal to rust underneath?
What do you think? Which way should it be done?