What is a built up roof?
As a system, built-up roofing (BUR) is a type of asphalt roofing that has been around for more than 100 years. It is one of the most common materials used on low-slope or flat roofs. They can also be used in combination with modified bitumen.
What are the layers of a built up roof?
Built-up roofing systems are most commonly applied with three or four layers of roofing materials to make up the complete roofing system. These layers are typically a base sheet, a fiber sheet, and then either one or two layers of bitumen.
What does built up roofing look like?
Built-up roofing, also called BUR, is the most common roofing material used on low-slope roofs. It is composed of alternating layers of reinforcing fabric and bitumen (asphalt) and is finished with a top layer of aggregate, such as stone or gravel.
How thick is built up roofing?
between two to four inches
How thick is built-up roofing? A BUR roof system comes in multiple layers, most often between two and four. The thickness depends on the materials used and the number of built-up roofing layers applied, but typically the selvage area ranges between two to four inches.
Where is built up roofing used?
Built-up roofing systems are an evolution of the asphalt roofing method. As compared to other roofing materials (such as metal roofs), BUR roofing membranes are created through a layering process of bitumen and reinforcing fabrics. They are most commonly used on low-slope roofs or flat roofs.
How is built up roofing installed?
First, contractors attach base sheets to the roof’s subsystem using roofing nails. Then, they use tar, concrete, adhesive, or asphalt to glue down felt over the top of the base sheeting. Next, roofers install a layer of gravel or cap sheets, which they then cover with a final layer of asphalt.
How long does a built up roof last?
If properly installed and maintained, a commercial built-up roof can last 40 years. There are a few other benefits of built-up roofing systems: Seamless and Waterproof – The continuous solid surface does not require joints or seams, removing the most vulnerable area for leaking.
What is 4-ply built up roofing?
A 4-Ply roofing system involves roofing felts that are typically four plies composed of layers of reinforcement such as fiberglass or polyester felts, with each ply being embedded in a full bed of hot asphalt/bitumen.
How many plys is a built up roof?
How is built up roofing applied?
ARMA defines a built-up roofing system as a roof where multiple layers of asphalt alternated with ply sheets (felts) are applied over the roof deck (vapor retarder) and, most often over insulation that is attached to the roof decking.