How Long Does A Flat Roof Last?

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The lifespan of a flat roof depends on a few factors. Hence what the materials are is the main factor. Besides, regular maintenance, natural calamities, etc also play vital roles determining how long a flat roof will last.

Let us walk you through the expected lifespan of different flat roofs.

How Long Does A Flat Roof Last?

The answer is a bit tricky. It may last only 10 to 20 years. For certain types of materials and regular good maintenance, it can last as long as 50 years. In general, we can expect a flat roof to last around 25 years.

Lifespan of a flat roof largely depends on its types. So, first of all, let’s have a clear concept on it’s type.  

Types of Flat Roof and Their Life-expectancy:

There are many types of flat roofs. Here we are going to talk about the most used ones:

1# Built-Up Roof (BUR): 

Built-Up Roof is one of the most common flat roofs. It is constructed with multiple layers of ply sheets and heated asphalt. You can layer the top of your roof for more durability. It is heavy due to multiple layers but still one of the most cost-efficient roofs. A Built-Up Roof can last for 15 to 20 years.

2# Rubber Membrane Roof (EPDM):

Ethylene Propylene Diene Monomer (EPDM) is a long one-ply rubber. It is engineered to resist damage from sunlight. These types of flat roofs have more vulnerability.

EPDM has a higher risk of leaks though it is easier to patch a leak than other types of roofs. The main weakness of this roof is the seams. Water can infiltrate through the seams that reduce life expectancy. The expected lifetime of the EPDM roof is 10 to 15 years.

3# PVC Roof:

PVC Roofs are hard to install. It takes very skilled laborers to install correctly. The roof is made of large pieces of PVC materials and waterproofing components. It has a great life expectancy that is up to 30 years.

4# TPO:

TPO is a newer type of roofing material. It has durability like PVC seams and is also cost-effective like EPDM. Its white surface reflects the sun’s rays to lower energy bills.

But after a few years, it can be cracked due to the hot sun. There can be major water infiltration. These types of roofs have a very wide life expectancy of 7 to 20 years.

5# Modified Bitumen Roof:

Modified Bitumen Roofs have layers like Built-Up Roofs. The Bitumen Layer is heated up like PVC for waterproofing. It is one of the most cost-effective roofing systems. You can expect this roof to last 10 to 20 years.

6# Spray on Coating:

Spray on Coating is a great choice for a commercial or industrial flat roof. The cost can vary because of materials. It can be as low as $3.00 per square foot. It can also cost $10.00 per square foot depending on the materials. Spray on Coating buildings can last up to 20 years.

7# R-Panel Metal Roof:

Instead of rubber, metal is used as a surface on this flat roof. Though roofing steel gives this roof greater life expectancy, the seams are vulnerable to water infiltration despite metal sheets being water-resistant. R-Panel Metal Roofs last 15 to 20 years on average.

8# Standing Seam Metal Roof:

The Standing Seam Metal Roof has a bit of angle. But as it is a common type of commercial roof, it is often classified as a flat roof. This roof is protected from moisture. Fasteners are used to keep the panels together which can rot away or show early signs of rust. This type of roof has the highest life expectancy of 20 to 30 years.

Disadvantages of Flat Roof:

The flat roof is not suitable for the areas where it snows. Snow can pile up on the flat roof and become a heavy burden. It can cause serious damage to the roof.

Rubber-based roofs are hard to install in snowy weather. The flat roof is popular around hot areas. But the cooling system can be costly for some types of flat roofs.


How Long Does a Flat Roof Last? The answers are different for different types of materials that are used for the flat roof. Most of them give a guarantee of around 15 to 20 years.

If your roof is not leaked or you maintain your roof with common guidelines, it can last much longer.

As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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