Built-up roofing, or BUR, is a roofing material that is commonly used for low-slope roofing. BUR is comprised of alternating layers of bitumen (asphalt) and reinforcing fabric before a top layer of aggregate, like stone or gravel gives it a finished look. This roofing system is preferred for low-slope, or flat roofing because it produces a continuous sealed roof surface. That’s in contrast to shingle roofing, which is not sealed and therefore requires a steep slope to shed water efficiently.

BUR roofing has been around for over a century as the most common system for flat-roofing until the rise of single-ply. Built-up roofing uses multiple layers of tar and gravel that acts as a watertight seal across the roof, protecting the lower layers from leaks and damage.

The Benefits of BUR Roofing

  • Trusted and Reliable—Commercial roofing contractors have used this method of roofing for more than 100 years, so we know it works.
  • Thick Coverage—BUR roofing consists of several plies that provide protection should the outer layers become worn or damaged. So there are plenty of backup layers in place if needed.
  • Highly Durable—The finished gravel or stone surface is extremely durable to last through daily wear and tear, so maintenance needs are reduced.


The modified bitumen roof system was introduced to the U.S. commercial roofing industry in the mid-1970s. It consists of modified bitumen membranes or roofing sheets that are made from modified asphalt through rubber (SBS) or plastic (APP), for enhanced stretch and flexibility. To ensure a lasting roof and energy savings for your business, we utilize the best materials in the industry and the finest techniques like modified bitumen roofing, or mod bit roofing (MB). It features an asphalt-based design for low slope or flat roofing structures, ensuring a highly durable product that is meant to withstand even the harshest of weather conditions.

Benefits of Modified Bitumen Roofing

  • Uniformity—Sheets used for a modified bitumen roof are produced with very tight quality control restrictions, for a consistent thickness and quality throughout.
  • Broad Temperature Range—Mod bit roofing is able to withstand the most extreme temperatures, both low and high, better than BUR roofing systems.

There is a decision to be made about which commercial roofing system would be better for your roof, whether it is for a new roof installation or a flat roof replacement, but it doesn’t have to be a difficult choice. Our flat roofing experts are here to help you choose the best roof considering your budget, your location, and your precise roofing requirements.   


It’s not always easy to choose the right commercial roofing for a given building structure. Commercial roofing requires more thought than residential roofing, given a unique design.

What to Consider for a Commercial Roofing System

When undergoing a commercial roofing installation, there are several considerations to keep in mind. Here are some of the most important ones to think about.

Building Usage

What is the purpose of the building itself? Is it intended to be a warehouse for inventory storage, a public space, or something else?
These questions are important because you will be able to address the need for certain features, like insulation for a publicly accessed building, or enhanced leak protection for valuable inventories.

Weather is a Factor

Where the building is located can have a major impact on which commercial roofing would work best. You will have to consider the possibility and frequency of extreme weather events, which are out of your control, or building code requirements, which must be adhered to.

Do You Expect Business Growth?

If your business is expected to grow over the coming years, you should ensure that your commercial roofing system is capable of growing with it. Thinking and planning ahead can ensure you do not need a flat roof replacement for a building expansion.

Various Roofing Systems

Consider the different commercial roofing systems available for your flat roofing needs. A metal roof replacement offers excellent durability and strength against high winds. It is also perfect for either a low slope, standard slope, or flat roof design, making flat roof repair easy. Asphalt is a popular option for commercial roofing, offering a very economical solution that is less costly than other systems. However, this type of roofing tends to require more maintenance over the life of the roof. It is best to contact qualified and experienced commercial roofing contractors to get a free estimate and solid advice. Your roofer can help you to select the proper material for your roofing taking each of these factors noted into consideration.