Can I Use Felt Paper Under Metal Roof

The main advantage of using felt roofing underlayment is cost.

Can i use felt paper under metal roof.

It s created by saturating paper or fiberglass mat with asphalt. When hot roof construction is done a roof with no ventilation a breathable underlayment is recommended. 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. Once again this is used on cold roof construction.

Make sure the product is designed to be used under metal. No 15 felt and no. 30 felt doesn t come with any kind of warranty as opposed to synthetic underlayment which can come up to a 50 year warranty. Both are good choices to use for metal roofing but there are some distinct differences to keep in mind.

This allows moisture that can become trapped in the roof deck to evaporate and escape. Underlayment must also act as a secondary weather barrier in case the roof fails. Felt roofing underlayment is one of the oldest types of roofing underlayment. Felt paper or not under metal rofing most codes and good roofing practice would require felt.

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. When it comes to metal roofing there are two main options for underlayment. Applications are similar for both materials and both stand up to the elements.

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. Felt roofing underlayment is typically available in two types. Synthetic or felt paper. 30 felt is typically thicker stronger and may be less prone to tearing or ripping off during installation or weather events.

Synthetic also alleviates some of the weight on the roof because it is so much lighter.