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A Complete Guide To Built-up Roofs

Posted on November 7, 2022

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A Complete Guide To Built-up Roofs

There are several ways in which you can improve your commercial roofing system. One of these ways is to install an entirely new roof. Over the years, the commercial roofing industry has witnessed a multitude of developments in terms of technology, and now there are a lot of choices when it comes to roofing materials to choose from.

Today we will talk about one of the most sturdy flat roofing systems, the built-up roof (BUR).

A built-up roofing system is a type of roofing used on large commercial buildings. It is solid and durable but also heavy and difficult to install. In the following paragraphs, we will cover the following:

  • What are built-up roofs?
  • Built-Up roof pros and cons.
  • Cost of a BUR roof system.

So let’s get started.

What is A Built-Up Roof?

A built-up roof is a type of flat roofing system that is made up of several layers. The roofer uses layer after layer of asphalt and ply sheets to create a built-up structure that’s finished with stone or gravel on the top. This composition helps improve the durability and resistance of your commercial roof.

A built-up roofing system is also known as a ‘tar and gravel roof. Tar is a sticky black substance that is usually made from coal and petroleum byproducts. Due to their similarities, built-up roofs are also known as the cousin of modified bitumen roofing systems.

built-up roof

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How Do Built-Up Roofing Systems Work?

The built-up roof is applied layer by layer. Due to this application, you can install this material only on flat, or low-slope roofs. The multiple layers of a BUR roofing system include a waterproofing layer, an insulation layer, and an outer protective layer.

First, the base sheet (felt paper) is applied to the deck so that the material is not directly adhered to the roof deck. Alternating layers of asphalt and reinforced fabric follow after the first layer, and the top layer is capped off with gravel for protection.

Built-Up Roof Pros and Cons

Every roofing system has its share of advantages and disadvantages. Below we have provided some reasons you should consider installing a built-up roof.

Pros Of Built-Up Roofs

Affordable Roofing System

One of the significant points that work in favor of built-up roofing systems is that they are quite affordable when compared to other commercial roofing materials. So you can install this roof even if you are on a tight budget.

Built-Up Roofs Offer High Durability

The purpose of any type of roof is to protect your home or business from the elements. Built-up roofs achieve this purpose. The BUR system is considered one of the most durable commercial roofing systems that can withstand extreme weather conditions. It’s made up of several layers, including asphalt shingles, felt paper, ply sheets, and tar paper. Modern built-up roof systems use high-quality insulation and roof coating to further increase the roof’s durability. These layers work together as a thick overlay to protect your building from natural elements such as rainwater and other harsh conditions expected in the Pennsylvania area.


As a commercial building owner, you’ll want to install a roof that will last for years to come. The roofing system you choose should cause infrequent trouble so you can focus on your business. The best thing about a built-up roof system is that it has a long life span, which makes it a great investment for commercial property owners.

Properly installed built-up roofs can last for up to 40 years, due to their durability and design. The materials on this type of roof are thicker than those on other roofs, and therefore, they can withstand harsher weather conditions, such as heavy snowfall or extreme temperatures (either hot or cold).

Good Protection Against Leaks

Roof leaks are one of the most common roofing problems in every roof type, be it residential or commercial. Built-up roofs are designed to be more watertight than shingles and other types of roofing materials, so they’re less likely to leak. Asphalt is excellent at keeping water away from different materials, and since a built-up roof includes layers of asphalt and other waterproofing materials, the roof will offer great protection against leaks. This means you can spend more time on work instead of worrying about the roof!

Energy Efficient

The type of roofing system you install on your property can help maintain the internal temperature of your building and plays an influential role in making your commercial space energy efficient.

Built-up roofs are an excellent option for saving energy costs. The top layer comes with a reflective coating which can combat the harmful effects of the sun. These roofs are also known for their insulating capabilities, which means that your home will be more comfortable, and you’ll be able to save money.

Built-Up Roofs Are Fire Resistant

The built-up roofing membranes are fire-resistant. Fire-resistant qualities carry a lot of importance in commercial buildings since there are higher chances of a fire breaking out. If you install a BUR roof, you do not have to worry about your roof catching fire as the top of the roof is covered with aggregates.

Built-Up Roofs Are Low-Maintenance

Built-up roofs are low maintenance, requiring less upkeep than other types of roofs. You’ll spend less time and money on repairs, and your roof will last longer.

Cons Of Built-Up Roofing

Despite being durable and long-lasting, built-up roofs do suffer some limitations. Some of these concerns are listed below.

Complex Installation

A drawback of built-up roofing is that its installation can be complex. Multiple layers make installation an expensive and time-consuming process, especially if we compare it to other roof installation methods. Safety needs to be considered as well since the use of hot asphalt can emit toxic fumes.

Whereas TPO and EPDM roofs (single-ply roof membranes) come in rolls and sheets, built-up roofs require more effort since they’re installed in large panels. They also take more time to install and be repaired than other roof types.

Due to the complex nature of the installation, it is recommended that you hire only the top roofing contractors in Pittsburgh to install the new roof, instead of trying to do it yourself.


Your built-up roofing system can be prone to blisters. These blisters are bumps on your roof that can occur when there is too much moisture built up between the layers of the material or between the material and the roof deck itself. This layer of moisture occurs when the roof is improperly installed or there is an undetected leak.

Blistering is more noticeable on hot, sunny days when the moisture expands in the heat, creating a bubble on your roof. When blisters or cracks appear on the roof it can lead to further damage, and even result in layers tearing.


Built-up roofs are very heavy, which can be a disadvantage. In a BUR roofing system, the number of layers depends on your preference. The more layers you install, the stronger the system will be. However, these sheets also add weight. A typical BUR roof can weigh 5-7 pounds per square foot, which is much heavier than single-ply roofing membranes.

The higher weight can put the roof’s integrity in danger and will cause the installation and repair processes to take much longer than other types of roofs.

What Is The Cost Of Installing a Built-Up Roof?

Before deciding on the type of roofing material, it is important to know about the cost of installation. More often than not, the cost is the driving force behind which roofing material gets chosen for a project.

As we’ve discussed above, the built-up roof system is affordable and can cost you around $2.50 to $6 per square foot. However, the cost of labor can be high, and the final cost depends on the following factors:

  • Size of the roof.
  • Type of the roof.
  • Area and conditions.

Can You Repair A Built-Up Roof?

Since the built-up roof consists of several layers, many flat roof owners are concerned about whether they can repair a built-up roof. If you also have the same concern, don’t stress, you can repair your built-up system.

Roofs are the first line of defense for your home and business. Whether rain, snow, or hail, our roofing systems face it all throughout their lifetime. However, over time they will incur damage and must be repaired, but the repairs will depend on the severity of the roof’s damage. Here are some of the most common issues to occur:

  • Blisters
  • Cracks
  • Tears
  • Open Joints/ Split joints

How Do I A Maintain Built-Up Roof?

Regular cleaning and maintenance of the roof are important. It can help your roof last longer and even save you money in the long run. Here are some tips for maintaining a roofing system.

Inspecting the Condition of the Roof

You should inspect the condition of your roof at least once every six months to ensure that there are no signs of damage or wear. This will help prevent further damage to your roof and ensure it stays in good working order. You can also contact us for a professional roof inspection service for your commercial building.

Repairing Damaged Areas

The damaged areas need to be repaired immediately before further damage occurs, or leaks start forming inside your office building. Otherwise, it could lead to water damage, which could be very costly to repair and even lead to replacing your entire roof.

Use Quality Roof Coating

You should coat the built-up roof properly, and choosing a roof coating with high reflectivity properties can offer great ultraviolet ray protection. If you don’t apply a roof coat, your roof has a higher chance of cracking from exposure to sunlight.

Install The Best Built-Up Roof For Your Commercial Property

A built-up roofing system is an excellent choice for many flat roofs or commercial roof buildings. It’s durable and reliable, which means you can count on it to protect your commercial property year after year. The good news is that you don’t have to do all the work yourself, we can help!

Hepler Contracting LLC is the #1 roofing company in Pittsburgh and the surrounding areas. Our team has a combined experience of more than 55 years, and we offer the best built-up roof installation services in the area. We can also provide you with roof repair and replacement services, and offer free quotes and estimates so you can get started on your project immediately. Contact us today at, (412)-694-8785 to learn more about how we can help you.

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