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Roof Membrane Installation: What You Need to Know

April 27, 2017 , In: Exterior Improvements, Outdoors , With: One Comment

A flat roof can add a unique look to your home, but if it’s not installed correctly or has been exposed to years’ worth of heat, snow and weather, it can start to leak in rain or snow. How can you fix this? By installing a roof membrane! It might sound like something grotesquely organic, but if you’re handy and don’t have any problems climbing a ladder, you can install one yourself.

What Type of Roof Do I Have?

Flat roofs might seem pretty straightforward, but there are actually three different types of flat roofs that might be installed on your home. Each type needs a different kind of roof membrane.

  • Built-up roof: This is made of layers of waterproof materials — tar paper or fiberglass membranes, commonly — alternated with tar and gravel. The gravel looks good if you actually see the roof, but it’s a super-heavy type of roof.
  • Modified bitumen: This is a peel-and stick-roof that can be installed quickly and easily. It’s not tear-resistant, so don’t expect to walk on your roof much once it’s installed.
  • Rubber membrane: Imagine sticking a bicycle inner tube to your roof. It’s a thick rubber that can be glued or anchored into place. It’s not good for places that get a lot of sunlight, though, because black rubber absorbs heat.

Built-up roofs, since they don’t provide a smooth surface, can make installing a new roof membrane tricky. The roof membrane adhesive may not stick well enough to create a waterproof seal.

roof top view

Installing a Roof Membrane

Now that you know what kind of roof you’re working with, it’s time to get to work. Make sure you’re keeping safety in mind — no one wants to fall off the roof, after all — and that you’ve got everything you need to get started.

Step 1 — Clean the Roof.

You can’t expect sticky stuff to stick to a dirty roof — it’ll stick to the dirt instead and you’ll be stuck with a bunch of useless roof membrane. If you’ve got a gravel roof, there’s no way to clean that down to a smooth surface, so you’ll need to lay down some thin plywood first.

Step 2 — Measure Everything.

You know the old saying measure twice, cut once? That goes double for installing a roof membrane. Measure your entire roof and make sure your measurements are as accurate as possible.

Step 3 — Cut the Membrane.

Now that you know how big your roof is, you need to cut the rubber to fit. Don’t do this on the roof — you’ll end up cutting it too short and having to start over. Don’t be afraid to cut it a little too long, though. A quick trim will make it fit perfectly.

Step 4 — Glue, But Be Patient.

This isn’t as easy as opening a bottle of Elmer’s Glue, after all. Read the directions, then read them again. Mix the glue according to those directions. Then lay down the glue on both the roof and the rubber — waiting until it becomes slightly tacky before pressing the two pieces together.

Step 5 — Rubber It Up!

The last step is to lay the rubber down. Once it’s down, use a roller to push out any air bubbles, and cover any seams between the rubber pieces with seam tape to ensure a perfect waterproof seal.

Why Should I Install a Roof Membrane?

Now that you know how to install a room membrane, why should you bother climbing up on the roof and installing it? The benefits of installing a roof membrane include:

  • New life: A roof membrane can add years of new life to your roof, and many materials even come with a warranty if properly installed.
  • Repair rather than re-roof: If your flat roof has started leaking, installing a roof membrane can repair the leaks. Also, a roof membrane can make it easier to repair leaks in the future.
  • Environmental protection: Adding a roof membrane to your home can help protect your roof from the ravages of the elements. Rain, snow and sun all take their toll on your roof.

A leaky roof is the probably the worst thing ever, especially if it happens in winter or the middle of the stormy season when it’s likely to do the most damage to your house. A roof membrane can help protect not only your roof, but also your home and your investment, for a fraction of the cost of replacing the entire roof. Take some time to learn how to install a roof membrane and you won’t regret it.

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Editor at Your Wild Home
Hey! I'm Megan. I am a dog-lover and enjoy exploring the outdoors. Your Wild Home covers a lot of topics, including (but not limited to) home improvement, home decor, construction, real estate, and sustainability. I enjoy writing in third-person and I am addicted to chocolate, coffee, and terrible puns. Learn more on my About Me page!
  1. Reply

    Megan, I’m really enjoying some of your articles. I wish I could say flat roofs were near and dear to my heart but there not after replacing 2 on commercial buildings I own in Dallas in the last 5 years.

    One built up and one membrane. The other way to do it is cover with metal. That will last the longest. I got a 25 year warranty on membrane and 15 year on built up. My biggest problem with them is they sure seem more susceptible to hail damage.

    You insure them but every time there is a claim you just are one step closer to becoming uninsurable.

    I know you are talking smaller residential roofs but I would advise anyone to stay away from the flat roof situation if they could. Flat is just that flat and water finding a flat place to sit vs a slope to run off makes it more susceptible to leaks.

    Thanks for the article.

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