Tar Paper Necessary Under Metal Roof

If you have a vertical seam where one piece ends and another starts make the overlap at least 6 inches.

Tar paper necessary under metal roof.

With metal roofing its also a good idea to put a layer of red rosin paper between the felt or ice water shield and the metal that way it wont potentialy stick to it and cause oil canning and would allow for expansion. Long term in service roof performance can be affected by several important factors including. Local building codes may specify a certain weight of felt paper but 30 pound paper is usually a good bet. There are pre printed lines on the tar paper that help show you where to end the overlap.

Our opinion is that on new asphalt shingle tile fiber cement slate and many wood roofs most roofing contractors apply an underlayment membrane of roofing felt tar paper or fiber reinforced roofing felt. The metal roofing system and its expected service life the climate at the building location roof slope and geometry and ambient conditions temperature relative humidity within the building. The slip sheet helps keep the metal from sticking to the felt paper while installing the roof. It provides trapped moisture from under the roof in low slope applications a path to drain.

Metal roofing underlayment is unique in requiring an extra slip sheet layer which is typically red rosin paper. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes. A special underlayment may be recommended by the manufacturers of specific roofing product and hybrid products.

Felt paper or not under metal rofing most codes and good roofing practice would require felt. It also creates a thermal break to minimize heat transfer from the roof surface to the structure. Felt otherwise known as underpayment is required when. Roofing felt is a layer of tar paper installed beneath the shingles to provide a backup waterproof membrane in case of leakage.