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Roofing Felt Paper

What is Roofing Felt Paper?

Roofing felt paper is usually made up of a base, which is made from natural materials like wood cellulose or they are made of synthetic materials (like polyester or fiberglass). The base material is either coated or saturated with a protective coating of a hydrocarbon (asphalt or bitumen which is also found in asphalt). It is this protective coating that repels water and allows the roof deck to breathe.

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At one time asphalt-saturated felt paper was the most popular material for roof underlayment, but it has since been replaced by synthetics as being the most popular.

There are typically two different types of asphalt roofing felt paper and they are No. 15 felt and No. 30 felt. No. 30 asphalt roofing felt is usually stronger, thicker, and will be less prone to ripping and tearing during installation or weather events. 

Why is Roofing Felt Paper used?

Roofing felt paper is used to protect your roof deck by ensuring water that gets under your shingles doesn’t cause damage to your roof. Often rain or snow can be wind-driven under shingles which then traps water underneath your shingles putting your roof and ultimately your home at risk of rot and mold, moisture damage, and leaks.

It is the roofing felt paper that roofing companies use to protect your structural roof decking, along with your roof shingles, to create a longer lasting and better-looking roof. 

Here are 7 more reasons to consider roofing felt paper:

  1. Extra weather protection
  2. It repels water
  3. While your roof is being worked on the roofing felt paper protects your roof deck.
  4. The look and uniformity of your roof can be positively influenced by roofing felt paper.
  5. In case of ice, snow, water damage the felt paper provides an additional layer of protection.
  6. In some locations roofing felt may be a necessity in order to meet Class A fire rating requirements.
  7. Not all roof decks lie perfectly square or flat, so adding a layer of roofing felt paper will give an even, uniform surface to install shingle on top of. This can help by stopping the projection of the not square roof decking through your shingles. 

What else can be used instead of Roofing Felt Paper?

Synthetic underlayment is more commonly used today, although more expensive than asphalt roofing felt paper.

Compared to asphalt roofing felt paper, synthetic underlayment is more tear resistant and it doesn’t absorb moisture. Due to synthetic underlayment not absorbing moisture it is resistant to fungal growth, wrinkle-free, and is also ultraviolet resistant for between six and twelve months. 

What if you don’t put Roofing Felt Paper on your roof?

Choosing to not put any kind of roofing felt paper on your roof is not the best choice for keeping your home dry and durable. The peace of mind you will have from knowing you have a properly installed roof that includes a roofing underlayment is priceless. Think of it as an investment in the well-being of your home and your safety. 

How is Roofing Felt Paper placed on a roof?

Roofing felt paper is placed on the roof deck or the roof sheathing that lies on top of roof’s joists and trusses. Your roof deck is typically OSB (oriented strand board) or can be plywood. The roofing felt paper is placed directly on top of your roof decking and is underneath your roof shingles.

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