Built-up roofing, or BUR, has stood the test of time. It’s been in use for over 100 years on flat roofs. Although the concept is nothing new, the materials and techniques used to install built up roofing have evolved over time.
BUR is composed of alternating layers of bitumen and reinforcing fabrics, with a layer of round pebbles in top to help with water shedding and reduce impact to the roof. The fabrics, also called ply sheets or roofing felts, are usually reinforced with glass fiber or organic materials to make them stronger.
Built up roofing has become a very popular choice for commercial buildings with flat roofs because of how well the top layer of rock protects the roof. It absorbs hail impacts, protects the roof from damage by foot traffic, keeps the waterproof layers from being exposed to sunlight and can last longer than other roofing types when installed properly.
BUR roofing is suitable for diverse surfaces, including glass-fiber sheets, aluminum coatings, or aggregate. BUR can consist of different materials and be applied in varying ways, but most BUR roofs consist of three main parts: bitumen, ply sheets, and surfacing materials.
Although it’s not a must, we recommend installing insulation to the roof deck before installing your BUR roofing. Insulation can save you big money on energy costs. It cuts heat transfer, preventing warm air from escaping a heated building in winter. Given how cold Colorado winters get, insulation is a smart investment.
When it comes to installing the actual BUR roofing, the first step is to affix the base sheet. The base sheet serves as the bottom ply and is mechanically fastened to the roof before any layers of bitumen and additional ply are installed. It may be attached to the insulation or, if you decide against insulation, directly to the roof deck.
There is an alternative to securing the base sheet to the roof: “ballasted roofing.” In this case, the base sheet does not adhere to the roof. Instead, large stones measuring 1.5 to 2.5 inches in diameter (instead of smaller aggregate) are used as the top layer, providing a heavily weighted surface that keeps the membrane in place.
Once the base sheet is installed, the first layer of bitumen (asphalt, coal tar, or a cold-applied adhesive) is applied. If asphalt or coal tar is used, the material is first heated, making it malleable and easy to spread. It’s then applied across the surface using a mechanical spreader or mop. If cold-applied adhesive is used, there is no need to heat the material first.
After a layer of bitumen is put in place, a ply layer is laid over it to create a secure bond. The process then continues (bitumen, ply, bitumen, ply, etc.) until the desired number of layers is reached.
As the finishing step, a top layer of stone, gravel, or similar aggregate is applied. This provides a uniform, finished look. It also safeguards the underlying layers, offering protection against elements like wind, rain, hail, snow, and sun.
BUR has several distinct advantages that make it an appealing roofing option such as:
The precise lifespan of a BUR roof will depend on the materials used as well as the climate. Colorado is known for its harsh winters, with plenty of snow, ice, and wind and of course the wild hail storms we get during the summer. Still, a well-installed BUR roof can last 15 to 30 years under these harsh conditions. In less intense climates, a BUR roof can easily last up to 40 years — it generally lasts longer in warmer climates.
Expert installation will make a big difference in how long your BUR built up roofing lasts. Overhead Roofing of Denver provides reliable, professional work with warranties to back it, giving you a built up roof that can withstand even the harshest of local weather.
There are many factors that go into the overall cost of having a new BUR roofing system installed, but it can be broken down pretty easily. Below are some of the factors to consider when figuring out pricing of your roof system.
Overhead Roofing Of Denver provides top-quality built up roofing systems to residential & commercial flat roof customers throughout Denver. We are proud of our skilled, detailed work, and will give you a sturdy, durable roof you can count on. Our residential & commercial roofing company consists of a friendly and professional team that doesn’t just get the job done right, we also ensure a spotless clean up afterward, so no mess is left behind. To get your free quote for BUR built up roofing installation, give us a call today.