The 5 Best Roof Felt Alternatives (Ultimate Guide)

Roof Felt Alternative

When you’re trying to fortify your home and shed, roofing is going to be a major part of your investment. Roofing is what keeps your stuff dry and acts as the barrier between your stuff and the elements. Roof felt is a layer of waterproof, tar-based paper that is meant to help keep water outside of your rooftop and slow down rot. In recent years, people have been searching out different alternatives to roof felt, but what are they?

Getting a roof felt alternative for your shed is a must if you want to ensure that your roof stays leak-proof. If you want to get an alternative for roof felt, you will need to look at synthetic materials such as:

  • EPDM
  • Rubber Asphalt Underlay
  • Rhepanol
  • Thermoplastic Polyolefin
  • Waterproof Ice And Rain Guard

If you want to make sure that your roofing stays dry during inclement weather, then you should know what alternatives are available to you. Let’s talk about this issue at length.

Before You Begin: Using Real Roof Felt Is Best

I want to preclude this article with a major caveat. The vast majority of shingle makers do not want you to use synthetic felts. This is because they can be more prone to leaks and are generally not seen as good choices for people who want long-term protection. As a result, if you choose to go with a roof felt alternative, then you might have your shingle warranty voided.

You really need to think long and hard about using a roof felt alternative. With that said, all alternatives to roofing felt are considered to be synthetic, chemical materials. It’s something to be aware of.

What Are The Best Roof Felt Alternatives?

Roof felt alternatives are being made every single day. For the sake of this article, we’re going to select the best candidates that we’ve found in terms of rating.


Ethylene Propylene Diene Monomer is the full name of this compound, but most people just prefer to call it EPDM. This is a single-ply synthetic felt that is made of dried out rubber that is poured into a sheet. Most people who are in the roofing industry will tell you that this is about as good as it gets.

Most people choose EPDM when they live in an area that’s known for extreme temperature. This is an ideal choice for people who live in areas that range from extremely hot to extremely cold all within a year. If you want to have a thin membrane that doesn’t add bulk to a roof but keeps things good to go, you’ll like this option.

Rubber Asphalt Underlay

Traditional roof felt is asphalt-coated paper. Rubber asphalt underlay is just a slight tweak on the classic concept. This is exactly what it sounds like. It’s a semi-synthetic underlay that involves a rubbery substance (can be rubber or a synthetic polymer, depending on the subtype) that is given a light coat of asphalt.

This underlay is fairly similar to standard felt in terms of functionality. The main difference is that this will have a more rubbery feel to it. There are several subgenres in this category, so you can always find one that works well for you. Sometimes this is also called polymer modified bitumen, or PMB.

Not sure if you’ve got PMB? Look at the color. Most PMB is black.


This is the most common name for this felt alternative in the UK, but once in a while, you’ll hear it stateside. The proper term for Rephanol, if you want to get chemical with it, is polyisobutene or PIB. This is considered to be one of the more durable options in terms of felt alternatives.

This material is best for flat rooftops, like the ones you might see in London or Brooklyn. This membrane is excellent for waterproofing. It can be bonded, fixed, or just sealed into place. A lot of roofers consider Rhepanol to be one if the best choices for roof felting that you can get outside of PMB.

Thermoplastic Polyolefin

Also known as TPO, this is another alternative to standard roof felt. It’s most commonly compared to EPDM in terms of both quality and application, so it’s pretty similar in a lot of ways. TPO, however, is very different from most others on this list. It’s meant to withstand high UV radiation ratings, which means that it’s great for reflecting light in high sunlight areas.

If you need to have felt that can offer a high level of insulation, then you will like TPO. To install it, you’ll need an air gun to melt the sheets together. With that said, it’s a fairly durable alternative that will give you years of good service. We would recommend this to anyone who wants to have a sturdy insulation layer to their roofing.

Unlike PMB, TPO is most commonly noted for being pale in color. So, you might see it in white or grey rather than black.

Premium Waterproof Ice And Rain Guard

From what we were able to uncover, this is not a specific chemical or style of roof felt alternative. However, it is a category of ultra-premium covers that are meant to be far more rugged than a typical felt alternative would be. These are meant to do just about everything you could want a layer of roofing do: protect against snow, ice, water, mold, sunlight, and every other threat out there.

If you can’t guess from the word “premium,” these are supposed to be the platinum standard as far as roof felts go. These are technically better than the real felt that is suggested. However, the prices of these types of guards would make most of us wince. Moreover, most people will find them to be overkill, especially if all you’re insulating is a shed.

Most of the time, it doesn’t make sense to get a premium guard unless you are storing something really unique in your shed. For example, if you are storing tools or a bunch of cleaning supplies in your shed, this is overkill. On the other hand, if your shed (somehow) has a Rolls Royce Phantom with fur lining, getting protection for it would make sense.

Which Roof Felt Alternative Is Right For You?

Honestly, every single shed that you’ll felt up is going to be different. What would work for one won’t for another, and some might not even be a good idea to even consider. When in doubt, it’s best to go for real roof felt rather than synthetic. Traditional roof felt is popular because it works in almost every single situation and also won’t void warranties placed on your roofing shingles.

The truth is, this is a matter that requires you to think about how much protection you want as well as what you want protection from. At times, you might not even need to have any roof felt at all. (This tends to be the case if you really don’t use your shed for much of anything important.) If you are not sure which type of roofing felt (or felt alternative) you should try to use, ask a hardware store employee. They usually know what will work.

Related Questions

Is roofing felt considered to be toxic?

One thing that has become increasingly popular among builders is a concern about the materials that they are using in their projects. Roofing felt looks like it would be toxic, but surprise! It’s actually not. The most recent studies deem it to be totally non-toxic and non-carcinogenic. So, it’s not about to give you cancer, even if things get toasty from that one heatwave.

The toxicity of roofing felt is not something you should have to worry about, at least in most cases. If the felt is being lit on fire, things might change. After all, that will change the chemical makeup of the felt.

Can you put new roof felt over old felt?

If you need to replace your felt, it’s generally smarter to remove the old felt by hand and then replace it with new felt. This is the easiest way to ensure that you won’t have any leaks and that mold from the older felt won’t contaminate your new roof felt. However, if you want to do things the fast way, you can place new roof felt over older felt. We do not suggest doing this as it can shorten the life of your felting.

Can roof felt be repaired?

Most people assume it isn’t repairable, but they would be wrong. Roof felt can be patched up in a pinch, even if it’s a large section that’s been damaged. However, if you are noticing large swaths (like over six square feet) of bad felt or if you notice that you’ve gotten mold under the felt, don’t patch it. It’s better to replace the felt that you see torn up.

When in doubt, always go for the replacement in full. It’s a safer way to ensure your roofing stays intact.

Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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