Can I Use Felt Paper Under Metal Roof

It s created by saturating paper or fiberglass mat with asphalt.

Can i use felt paper under metal roof.

The temperature under a metal roof can get very hot and over time 30 felt which is composed of asphalt will dry out quickly leaving not much in the way of a secondary weather barrier. Felt paper or not under metal rofing most codes and good roofing practice would require felt. Synthetic or felt paper. The main advantage of using felt roofing underlayment is cost.

Conversely felt underlayment is appropriate in conjunction with ice dam protection at eaves and other critical transitions in cold climates. Felt roofing underlayment is one of the oldest types of roofing underlayment. Underlayment must also act as a secondary weather barrier in case the roof fails. This allows moisture that can become trapped in the roof deck to evaporate and escape.

30 felt doesn t come with any kind of warranty as opposed to synthetic underlayment which can come up to a 50 year warranty. Once again this is used on cold roof construction. However contractors now recognize the benefits of synthetic underlayment for metal roofing particularly when it comes to its tolerance to heat and ultraviolet uv radiation. For the most part though felt paper and its synthetic counterpart both do a great job of weatherproofing the decking before shingles can be applied.

30 felt is typically thicker stronger and may be less prone to tearing or ripping off during installation or weather events. Architectural metal roofs with felt underlayment are best suited for buildings with proper slope and low moisture loads in dry or arid climates. Synthetic also alleviates some of the weight on the roof because it is so much lighter. Applications are similar for both materials and both stand up to the elements.

Make sure the product is designed to be used under metal. Felt roofing underlayment is typically available in two types. Both are good choices to use for metal roofing but there are some distinct differences to keep in mind. 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.

Traditionally metal roofs have used standard 30 pound felt paper underlayment.