How To Install Metal Roof On Shingles. In simple terms, if the asphalt shingles are not used to support the metal roof, then you can install a metal roof over the asphalt shingles. Venting—the eaves to vent the roof, holes are cut in the old roof above the soffit, which pulls air through the soffit vents underneath.
Also, try to avoid using nails. In sunny climates like san diego, exposure to uv light can greatly reduce the lifespan of asphalt shingles. Having a metal roof without a buffer will end up causing the shingle granules to slowly wear away against the roofing panes.
Next, use 1 ¼ inch nails to secure some metal edging to the perimeter of the roof.
Can i install a new metal roof over shingles? “yes you can.” and by doing so, you save in the labor and hassle of tearing off the old roof and you won’t be contributing to filling our landfills. Now the second method usually involves installing the metal roof on top of the traditional shingle roof using battens and purlins. Also, try to avoid using nails.