Putting Metal Roofing Over Old Roofing

Reroofing is the practice that involves installing a new roof over an existing one.

Putting metal roofing over old roofing.

Align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof line. The installation of metal roofing is often easier and faster than other roof types and because of its simple design and generally large size can actually be installed directly on top of existing roofing materials like asphalt shingles and foam roofing. Cool outside air then travels under the shingles to the vented ridge detail 2 pulling out moisture and heat. Installing metal roofing over existing roofing material can usually be successfully.

Installing a metal roof over shingles can also result in an increased chance of trapped water vapor and moisture between the new roof and old roof resulting in new mold and rot. Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing. However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life. This provides added protection against ice dams.

But is this a good idea. By removing the old roof before the new roof s installation you are able to give the underlayment a thorough inspection to ensure there are no damages that could. Doesn t provide the flattest surface for the metal roofing to be installed over each course of shingles is about a 1 8 higher than the course just below it. March 11 2020 by safe harbor roofing.

Pros and cons for metal roofing installation. Should you tear off the old roof and start over or simply remove the fasteners from the existing roof and install another roof over it. Be sure the larger edge is laid so that the small edge of the next panel will overlap it. Metal over metal retrofit considerations there are a number of issues a roofer will have to deal with when it comes to metal over metal retrofits but listed below are a few where the use of a roof hugger.

Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option a properly installed layover roof can look and function as well. To vent the roof holes are cut in the old roof detail 1 above the soffit which pulls air through the soffit vents underneath.