If you have a screened-in porch with a low slope roof or a flat roof facet anywhere, you’re going to need something different than asphalt shingles. Even if you get an entire asphalt roof replacement, that specific low slope area has to have a membrane or metal roof installed over it.
Both are great options, but the commonly used and cheaper option is a membrane roof system. But you’ll have more than one membrane roofing choice.
Here at Bill Ragan Roofing, we want you to have all the information you need before making a purchasing decision. That’s why we’re going to break down the types of roof membrane for your flat or low slope roof.
By the end of this article, you’ll learn the 3 types of roof membranes, an idea of the cost of a membrane roof system, and the reason you must have a membrane on a low slope roof.
After all that, there's a checklist that'll help you find a great roofing contractor for your membrane roof.
3 types of roof membranes for a flat or low slope roof
The 3 types of roofing membranes are EPDM, TPO, and PVC. All 3 have their place in residential roofing, but it depends on the look you want and what rooms are directly below the roof.
1. EPDM membrane roofing
EPDM (ethylene propylene diene terpolymer) is a synthetic rubber black membrane commonly used in commercial and medical facilities. While it’s used mostly in commercial, EPDM has its place in residential roofing.
Because it’s a black membrane, I wouldn’t recommend using it over a bedroom or living space because of the heat it’s going to absorb. However, I recommend EPDM for a roof over a garage or another non-living space you can see from a window because the black won’t get as dirty as a white membrane.
EPDM is extremely durable and is basically like having a bulletproof rubber roof system. Because of this durability, you can expect to get 25 to 30 years out of a fully adhered 0.060 thickness EPDM roof.
2. TPO membrane roofing
TPO (thermoplastic polyolefin) is a single-ply white membrane used in both commercial and residential roofing. Unlike EPDM, TPO’s white membrane reflects heat instead of absorbing it.
If you have a flat roof or a low-slope dormer over a bedroom, TPO is a great option because it’ll keep the room cooler. You still have the option to choose to get it over a non-living space like EPDM.
But remember, if you have a window that looks over the membrane, white will get dirtier a lot quicker than a black membrane. Both will do the job of keeping the flat roof leak-free, it just depends if you care about what you’ll see when looking out the window.
While it’s not as durable as EPDM, you can still expect to get 25 years out of TPO membrane as long as it’s installed properly.
3. PVC membrane roofing
PVC (polyvinyl chloride) is also a single-ply white membrane used in commercial and residential roofing. PVC is also a great choice for any flat or low slope over a living space or bedroom.
Besides being a white membrane, PVC and TPO are very similar in their characteristics besides their chemical make-up. Even the installation process is pretty much the same.
The only major difference is that PVC is a bit more flexible and has been around longer than TPO. Like TPO, you can expect to get 25 years out of a PVC roof as long as it’s installed properly.
How much does membrane roofing cost?
There are a few factors that determine the cost of a membrane roof. One factor is the type of insulation that you're using under the membrane.
For example, using insulation that’s thick enough to insulate the entire structure will cost more than if you're just using fabric insulation and gluing the membrane to it. Another huge factor is the size of the roof that’s getting the membrane.
A good rule of thumb is to budget between around $14.00-$17.00 per square foot for a smaller membrane roof and around $12.00 per square foot on slightly larger projects. When you get into larger commercial projects, the cost per square foot drastically decreases.
Why do you even need a membrane roof system?
If you have a roof or a roof facet that’s pitch (aka steepness) is below a 2:12 (less than 2 vertical units up for every 12 horizontal units out), it’s considered low slope. It needs to be waterproof because water won’t run off as fast on a low slope or flat roof as it would on higher pitched roofs.
Because asphalt shingles aren’t meant to have sitting water on them, the shingle manufacturer’s installation instructions and building codes state you can’t install asphalt shingles on a roof with a pitch below 2:12. This is why a membrane (or metal) roof system has to be installed to prevent leaks from coming into the space below a low slope or flat roof.
If a roofing contractor even mentions putting shingles on a low slope roof, don’t go with them.
Find a great roofing contractor for your membrane roof with this checklist
Now you know the 3 types of membrane roof systems, an idea of how much it costs, and why you need one in the first place. But before reaching out to a roofing contactor for your membrane roofing needs, you need to know how to spot a reputable company.
The best way to do this is by asking the right questions when calling or meeting with potential roofing contractors. To help you do this, we created a checklist of 16 questions every homeowner needs to ask a roofing contractor.
The checklist also contains the right answers a reputable roofing will give back. Don't let your membrane roof investment be ruined right from the start by making the wrong hiring decision.
Keep going to get your checklist of questions to ask a roofing contractor.
Since 1990, the team at Bill Ragan Roofing has proudly helped homeowners in Nashville with all of their roofing needs. Whether it’s to give you a new roof or to fix your roof leak, you can count on us to provide high-quality workmanship that gives you peace of mind.
If you're in the Nashville area, don't hesitate to contact us for any of your membrane roofing needs.