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What is a Low Slope Roof? (& What Roof System is the Right Fit)

October 23rd, 2020 | 5 min. read

What is a Low Slope Roof? (& What Roof System is the Right Fit)

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Are you ready for a new roof? Do you have a roof that is considered “low slope”? 

If so, you’re probably wondering what that even means. Luckily, we’re here to help you understand this style of roof. 

The team at Bill Ragan Roofing has taken care of low slope roofs in the Nashville area since 1990. We know what it takes to maximize the life of your roof. When you work with us, you’ll never worry about your roof again. 

So, what is a low slope roof? Always eager to educate on all things roofing, I’m going to answer that question. 

By the end of this article, you'll learn about roof pitch, what a low slope roof is, and what roof system(s) is right for this kind of roof. 

What is roof pitch? 

Before we get to what a low slope roof is, you need to know about roof pitch. Roof pitch is simply the steepness (angle) of your roof. 

Your roof’s pitch will be a ratio that is calculated by the number of inches or feet it rises vertically for every 12 inches or feet it extends horizontally. For example, a roof that has a 4/12 pitch will be 4 inches (or feet) up for every 12 inches (feet) out. 

Don’t try to get on your roof to measure its pitch. You’ll learn your roof’s pitch when it’s inspected by a local roofing contractor for your roof replacement

What is a low slope roof?

Now that you know about roof pitch, you’re ready to learn what a low slope roof is. A low slope roof is a roof that is not steep enough, per the shingle manufacturers or codes, to put shingles on it. 

what is a low slope roof

Remember, roof pitch is how steep your roof is. A roof is considered a low slope when the roof’s pitch is below a 2:12. This means your roof is less than 2 vertical units (inches or feet) up for every 12 horizontal units out. 

Because shingles can’t be installed on low slope roofs you won’t be able to get the commonly used asphalt shingles. However, there are still great options for your low slope roof.  

What roof system is the right fit for a low slope roof?

You just learned what a low slope roof is and what is considered a low slope pitch. If shingles can’t be installed on low slope roofs, what type of roof system can?

Continue reading to learn what type of roof system can be installed on your low slope roof. 

Membrane roof systems 

Water won’t run off as fast on low slope roofs as it would on higher pitched roofs. Because of this, low slope roofs need to be waterproof. 

That’s why the most common option for low slope roofs are membrane roof systems. Membrane roof systems are sheets, either 5 foot, 10 foot, 20 foot wide sheets of rolled synthetic, water repellent membrane. 

membrane roof system

There are 3 types of membrane roof systems: EPDM, PVC, and TPO. TPO and PVC usually come in white and are reflective, which makes it easier to keep the rooms below cooler. 

EPDM is a rubber and black membrane that is commonly used above medical facilities. However, all 3 have their place in residential roofing. It all depends on the look you want and what rooms are directly below the roof. 

For example, if you can see the roof outside a window, you're probably not going to go with a white membrane because it's going to be dirty in six months and it's going to look unsightly. On the other hand, if a bedroom or living space is below, you’ll probably go with TPO or PVC to keep the room cool. 

Metal roof systems 

Another type of roof system used on low slope roofs (especially in commercial) is metal. There are 2 types of metal roof systems, standing seam and screw-down. 

A standing seam metal roof system is a series of panels that are locked together at the seams or seamed mechanically. This allows for panels to expand and contract freely when the metal heats up.

standing seam metal roof

A screw-down panel is just what it's called; it's screwed down. The screws are screwed through the panel, which leaves no room for expansion and contraction. I would not recommend putting a screw-down panel over a heated space such as your home or office due to its lack of expansion capability.

screw down panel metal roof

If you’re considering a metal roof for your low slope roof, I recommend going with a standing seam metal roof system. To learn more about the metal roof systems, read this article on standing seam metal roof vs. screw-down panel roof.  

Learn everything you need to know about low slope roofing

Now you know what a low slope roof is. You also learned about roof pitch and what pitch is considered a low slope. 

Remember, your low slope roof isn’t steep enough to put shingles on it. Your low slope roofing options are a membrane roof system or a metal roof system.

Both are great roof systems for low slope roofs, but it’ll be up to you to determine which one is right for you. But before making your decision, there's still more you need to know about low slope roofing. 

Because we want you to have the information you need to make the best decision, we have a video breaking down all the important things you need to know about low slope roofing. 

Since 1990, the team at Bill Ragan Roofing has provided high-quality roof replacements (including low slope roof systems) to residents of Nashville. Our workmanship ensures you get the most life out of your roof and we're proud to offer a lifetime warranty to back it up. 

To learn what you need to know about your low slope roof, check out Low Slope Roofing: What You Need to Know

the complete guide to purchasing a roof

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