Your flat roof replacement is a little different than a standard roof replacement. Because water won’t run off a flat area like it does standard roof pitches, it needs something waterproof.
The problem is knowing which waterproof material to choose. That’s why we’ll give you the waterproofing applications we recommend to homeowners for their flat roofs.
For over 30 years, the team at Bill Ragan Roofing has helped homeowners find the perfect material fit for their upcoming roof replacement. Now I’ll do the same for you and your flat roofing project.
Let’s get to the 3 best waterproofing applications for your flat roof and how much they cost.
1. TPO roofing membrane
TPO roofing (thermoplastic polyolefin) is a single-ply white membrane used in commercial and residential roofing. Because a TPO roofing membrane is white, it reflects heat instead of absorbing it.
This makes TPO a great option for a flat roof over a bedroom because it’ll keep the room below cooler. Of course, you can still use it over a non-living space like a garage or covered patio.
No matter where the TPO roofing membrane is installed, it’s important to consider the look of a white membrane. The white will get noticeably dirty over time, so you need to determine if seeing it from a window is a big deal.
If you don’t care about the look or can't see the roof, you won’t have to worry about this. But it’s just something to keep in mind when making your final decision.
Just know the “dirtiness” doesn’t affect the functionality of the membrane. As long as your TPO roofing membrane is installed properly, you can expect to get around 25 years out of it.
2. PVC roofing membrane
PVC roofing (polyvinyl chloride) is a single-ply white membrane used in both commercial and residential roofing. Like TPO, the white membrane reflects heat instead of absorbing it.
Besides their chemical makeup, a PVC roofing membrane has very similar characteristics to a TPO roofing membrane. The installation process for both is even pretty much the same.
The only real difference is that PVC roofing is more flexible and has been around longer than TPO roofing. Just like TPO, a PVC roofing membrane is a great option for a flat roof over a living space because it’ll keep the room below cooler.
But you’ll also have to consider how dirty the white will get when seeing it from the window. Remember, it will have no impact on the functionality of the membrane roof.
You can expect to get around 25 years out of a PVC roofing membrane as long as it’s installed properly.
3. EPDM roofing membrane
EPDM roofing (ethylene propylene diene terpolymer) is a synthetic rubber black membrane mostly used in commercial and medical facilities. However, EPDM roofing has its place in residential roofing and is becoming more popular.
Because an EPDM roofing membrane is black, it’ll absorb heat instead of reflecting it like the white membranes. For this reason, I wouldn’t recommend using it over a bedroom or living space.
While it doesn’t have the advantage of reflecting heat like a white membrane, you don’t have to worry about it getting as dirty. So, you don’t have to necessarily worry about the aesthetic of an EPDM roofing membrane if it can be seen from a window.
EPDM is recommended for a flat roof over a garage or a non-living space, but it can still be installed over a bedroom or living roof. Just make sure to consider the heat absorption of the black EPDM membrane roof system when making your final decision.
EPDM roofing membranes are extremely durable, and we like to say it’s like having a bulletproof rubber roof system. Because of this, you can expect to get around 25 to 30 years out of a fully adhered 0.060 thickness EPDM roof.
How much do the 3 best waterproofing applications for a flat roof cost?
After learning about the 3 best waterproofing applications for your flat roof and their lifespans, there’s still one more important thing to know. This is how much they’ll cost you.
Just know that it’s impossible to give you an exact price for the roofing membranes because of all the different cost factors. However, I can give you an idea of the budget you’ll need for a membrane roof system.
You can expect a new roofing membrane to cost around $14.00-$17.00 per square foot for smaller projects and around $12.00 per square foot for slightly larger projects. While I can’t possibly get into all the cost factors here, there are a couple that determines where you’ll fall in the price range above.
The first one is the type of insulation used under your roofing membrane. Using insulation thick enough to insulate the entire structure costs more than using fabric insulation and gluing the membrane to it.
The second factor is the size of the flat roof getting the roofing membrane installed on it. If you have a smaller flat roof, the cost per square foot will actually be on the higher end of the price range.
For larger flat roofing projects, the cost per square foot has the opposite effect and drastically decreases.
Get the tips you need to find a great roofing contractor for your flat roofing project
Now you have an idea of how much you’ll pay for a membrane roof system on your flat roof. After reading this article, you should have an idea which one of the best waterproofing applications is right for your roof.
Just know there are other options out there, like modified bitumen. However, these are the 3 we recommend and are the most popular among the homeowners we work with.
After determining which one is right for you, you’ll need to find a great roofing contractor to install it. This is an important decision that you can’t take lightly, especially when it comes to waterproofing.
Because it’s such an important decision, you need to know how to spot a great roofing contractor out of the sea of options in your area. That’s why we want to give you 7 tips to find a great roofing contractor for your flat roofing project.
Since 1990, the team at Bill Ragan Roofing has proudly helped homeowners in Nashville and surrounding Middle Tennessee areas with all of their flat roofing needs. Whether it’s for a flat roof replacement or to fix a flat roof leak, you can count on us to provide high-quality workmanship that gives you peace of mind.