Tar Paper Necessary Under Metal Roof

Felt paper or not under metal rofing most codes and good roofing practice would require felt.

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. A special underlayment may be recommended by the manufacturers of specific roofing product and hybrid products. 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. If you have a vertical seam where one piece ends and another starts make the overlap at least 6 inches.

There are pre printed lines on the tar paper that help show you where to end the overlap. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. 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. Felt otherwise known as underpayment is required when.

Sometimes called roofing felt underlayment roofing tar paper or roll roofing this is a layer of protection installed between the roof deck and the roofing shingles. Local building codes may specify a certain weight of felt paper but 30 pound paper is usually a good bet. Roofing felt is a layer of tar paper installed beneath the shingles to provide a backup waterproof membrane in case of leakage. The slip sheet helps keep the metal from sticking to the felt paper while installing the roof.

This thermal break promotes energy efficiency by stopping conductive heat transfer much like the air space between multiple panes of glass in a thermal pane window. 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. It also creates a thermal break to minimize heat transfer from the roof surface to the structure.