Commercial, Mixed-Use and Strata Roof Maintenance in Vancouver, B.C.

Why Is There Gravel On A Flat Roof Or Low Sloped Roof?

Why Is There Gravel On A Flat Roof Or Low Sloped Roof?

As a roofing contractor, people often ask me why is there gravel on flat roofs. As no other roofing system needs small stones on it. So, what is so unique if the Tar and gravel roofing system? Let’s find out below.

Gravel is placed on flat roofs because this type of roofing system needs gravel to protect its inner layers from the elements and wear and tear caused by them and the sun’s harmful Ultra Violet rays.

In this article, we will dig deep into the Tar and Gravel roofing system and explore its unique features if it.

What Are Tar & Gravel Roofs Or Built-Up Roofs?

A tar and gravel roof, also known as a built-up roof (BURs), is a type of roofing system that consists of multiple layers of roofing felt/fibreglass, asphalt and gravel. Pressed together with heat. These roofing materials make a durable and long-lasting roofing system when combined.

The gravel on a flat roof is not just scattered all over the roof, but embedded in it, to protect the bottom layers from the elements and UV light. Embedding gravel is necessary for it to stay in place for a long time.

The weight of gravel used on a BUR depends upon the layers of roofing below, the structure of the building, your location and the climate of your region. Even though the asphalt roofing system is a good one in itself, gravel just enhances its lifespan and durability.

Reasons Why They Put Gravel On The Roof

Two of the most important reasons to put gravel on a flat roof are explained below:

1) To Protect Built-Up Roofs

As commercial and industrial buildings mostly have flat asphalt roofs. Gravel is often seen on their roofs. These BURs need to be protected from UV rays and other natural factors.

Gravel protects the built-up roofs from extreme weather conditions. And helps in keeping the roofs cool by reflecting heat away from the building. In addition, gravel also prevents leaks by filling in any cracks or gaps in the roofing materials.

It is important to note that the gravel must be properly installed and maintained. If you are considering adding gravel to your built-up roof, be sure to consult a professional roofing contractor to ensure that it is done correctly.

  1. To extend the life of the roof: The lifespan of a built-up roof can be extended by adding a layer of gravel. This is because the gravel protects the asphalt and tar from UV damage and wear and tear.
  2. To provide insulation: Gravel can also help to insulate the building by reflecting heat away from the roof. Gravel also reflects heat away from the underlying roofing materials, helping to keep the building cooler in summer making it energy efficient.
  3. Gravel provides excellent drainage and can help to prevent ponding water on the roof, which can lead to leaks. Overall, a gravel-surfaced BUR is a durable, low-maintenance option that can provide many years of service.

2) To Weigh Down The Roofing Materials

Embedding gravel on a flat roof is a popular way to weigh down the roofing materials. This method is often used in areas where wind storms are a problem. The gravel helps to keep the roofing materials in place and prevents them from being blown away.

Not only is this method cost-efficient, but also quick and easy. Just be sure to use enough gravel to adequately weigh down the materials, and make sure it’s evenly distributed across the surface of the flat roof.

  1. Durability: Gravel on a flat roof is used to achieving more durability and a longer lifespan. If the roof is properly maintained, it can last up to 30 years.
  2. Resistant: Gravel on a flat roof provides excellent protection against extreme weather including wind storms and hail. It also adds a fire-resistant element to the building.
  3. Low Maintenance: It is also low maintenance and easy to repair if any damage does occur. Build-up roofs require only annual inspections and occasional repairs, so they are low maintenance and can be replaced as needed.
  4. Economical: Gravel on a flat roof is an economical choice for commercial roofing. As it requires little upkeep, which saves businesses money in the long run.

Maintenance Requirements of a Tar and Gravel Roof

A BUR is a low-maintenance roofing system. However, there are a few things you should do to keep it in a good condition.

  1. Regularly inspect your roof for signs of damage. This includes cracked, missing, or loose gravel or holes in the tar paper beneath.
  2. If you notice any damage, repair it immediately to prevent further deterioration.
  3. Make sure the gutters and downspouts are clear, so that water can drain properly from the roof.
  4. Trim trees and shrubs around the building so that they don’t rub against the roof or drop leaves or branches onto it.

Repairs Needed Of Tar And Gravel Roofing System

As mentioned above regular maintenance is enough for a BUR to last long.

Damage to a tar and gravel roof can occur from a variety of sources, including severe weather, falling debris, animal activity, and improper installation or maintenance. Leaks are the most common type of damage, but other problems can include ponding water and leaks due to improperly installed penetrations.

A comprehensive maintenance and repair program should cover inspections, cleaning, patching leaks, sealing seams and flashings, replacing damaged shingles, and adding additional gravel as needed.

However, contact a roofing professional immediately, the repairs needed are not covered in a maintaining program.


We hope this article has answered the question of why is there gravel on a flat roof. If you have any similar questions regarding the roofing industry, drop them in the comment section below. We will answer them in our future posts.

Also, if you have a flat roof and need a professional roofer to take a look at it feel free to connect with us TODAY!

Leak-Stop is a one-stop destination to meet your roofing-related requirements. We offer roof repair, replacement, maintenance and inspection services all over GVRD (Greater Vancouver Regional District). We offer a free inspection to first-time clients.

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