Updated: Oct 12, 2016

roof underlayment

Roofing Underlayment Reviews:

  • What is roofing underlayment?
  • Benefits of using synthetic roofing underlayment
  • How much does roof underlayment cost? Which should I buy?

No one wants to have to redo their roofs, but if you stay in your home long enough it's one of those homeowner expenses that is hard to avoid. It's a big expense and you should be fully aware of all the products available when redoing your roof. Considering it's been over 20 years since I last had a roof done, I didn't realize that the traditional roofing paper (underlayment) has changed a bit. You typically see roofing companies using the 15lb or 30 lb felt underlayment. I had a new roof done in 2013 and the roofing contractor asked me if I was familiar with the new synthetic underlayment. These new types are lighter, stronger, and can hold up to the elements (when exposed) much longer than the regular felt roofing paper.

I got the chance to see both types up close and feel the difference. I have to admit that the synthetic roof underlayment (FelTex) seemed strong, but compared to the 30lb felt roofing paper, I just couldn't imagine it being better. I was assured by several people in the roofing industry that it was good quality and that the product would hold up just as well (if not better) than the traditional roofing paper. I was going with asphalt shingles and most people said the synthetic roofing underlayment would be just fine. Here is the comparison I did on my own between the two types of roofing paper.

roof underlayment


Video on How To Install GAF Roof Deck Protection & Roofing Underlayment:



Choosing a Roof Underlayment

I started off with the Ehow website and their article on types of roofing paper (http://www.ehow.com/list_6727607_types-roofing-paper.html). There are 3 main types - roofing felt, synthetic roofing paper and self-adhering roofing paper. Let's start with what the roofing underlayment does for your roof. No matter which type you choose they are all designed to give you that protective barrier between the plywood roof and the shingles. Your ultimate goal is to keep moisture and condensation from getting into your attic and the roofing paper acts like a 'vapor barrier' if by chance the shingles fail. Felt roofing paper is quite thick (saturated with asphalt) and it's water resistant (not waterproof). Felt underlayment comes in 15 and 30 lb options. Of course the 30 lb is considered the better choice for climates like ours in the Pacific Northwest, but it is not necessary in other climates. As we mentioned above, the synthetic underlayments like FelTex are stronger and more durable than felt and substantially lighter. Are they better? Depends on who you talk with. The pluses to the synthetics are that they give the roofers better traction while standing on them, can go up to 6 months in the elements without failing, and they are more resistant to abrasions than felt.

What does all that add up to? You might want to give them a try in your neck of the woods. The best article I could find was on Nyashi.com (SEE IT HERE). It compares synthetic roofing underlayments - although it's an older article it will still help guide your decision. There are some great Forum discussions about roof underlayments on Roofing.com and Contractortalk.com. I always like to see the discussions between actual roofing contractors on new products and listen to their feedback. From all that I heard around here from experienced roofers, it seems that the synthetics are just as good as the felt paper, so either way you should be happy.

The top brands are Feltex, Tarco, IKO, and Owens Corning, DuPont, and GAF. You can buy the roofing paper in a variety of sizes - we saw a 4 foot by 250 foot roll for $115 at Lowe's and that seemed expensive. Much of the other material we found online was roughly $50 for a similar 30lb felt paper. Definitely shop around for the best prices. In most cases your roofing company will order the shingles, roofing paper, flashing, vents, etc. all from a building/roofing supply store and it will be delivered. You can browse the best selling roofing underlayments online here.

best roofing underlayment

Best Roofing Underlayment:

The TYPAR Surround S.R. Roof Underlayment ($33) comes in rolls that measure 45" by 53.4 feet. When you compare the TYPAR to traditional 30# felt roofing paper, you can quickly see the advantages to using it. The TYPAR is 10 times stronger and 10 times lighter than 30# felt. Therefore, it's tear resistant and very easy to carry up onto the roof top. They are slip resistant as well, which helps keep those that are installing it be safe during the process. Surround SR Underlayment is used by roofing crews all across the United States and considered a great alternative to felt. The underlayment creates a secondary water barrier on the roof, so leaks and water damage due to rain and storms are eliminated.

The Grace Ice & Water Shield 36" x 36' Roll is another product that is recommend in areas that get more rain and snow. The rubberized asphalt layer actually seals around roofing nails, so they are totally water resistant. The roll bonds to the roof deck easily and the membrane will not dry out (rot) or crack. Some reviews mention that the backing is so sticky it's hard to not get stuck to it yourself. A second set of hands would be a good idea to get it layed down properly.

To check out how to install roofing underlayments - click the image below to go to video.

roofing underlayments roofing underlayment

Synthetic Roof Underlayment:

RECOMMENDED - Talk with local roofing companies and see which products they recommend. Most have websites that are loaded with their favorite brands for roofing paper. Two of the most common synthetics are Titanium UDL from Interwrap and FelTex from System Components. Others are Sharkskin Comp, Tri Flex 30, and Roofshield. All range from 20 to 30 years in terms of warranty. The cost per square foot goes from $.10 up to about $.40. FelTex is the one that was recommended by my roofer, although we didn't go with it. FelTex is a woven polypropylene fabric that features a waterproof backing. One roofer mentioned online that he couldn't get the FelTex to take a chalk line. Synthetic underlayments are good if you plan on leaving the roof with just roofing paper for a few months - not sure why you would do that. Also, they are perfect for homeowners who may not check their roofing shingles that often and need to know that the roofing paper can hold up when perhaps the shingles have failed. The long term durability is not totally proven amongst roofers, eventhough the manufacturers assure us that they will last longer than the felt option.

More videos and resources are here on our Roof Underlayment Resource Page.

synthetic roof underlayment

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