Built-up roofing gained popularity during the 1970s. More commonly known as tar and gravel roofs, this material consists of alternating layers of bitumen and reinforcing fabrics. Together, these create a finished membrane. The bitumen used includes asphalt, cold-applied adhesive, or coal tar.
Built-up roofing is nothing new. The concept has been around for over 100 years, although the material and its installation certainly have evolved during that time. Modern built-up products incorporate a rigid insulation layer for improved energy efficiency.
Most built-up roofing is comprised of three parts: bitumen material, ply sheets, and one or more surfacing materials. The bitumen can be either “hot,” meaning it is heated so that it liquefies during installation, or it can be “cold,” which is more like an adhesive and is not heated. Cold built-up roofing can be sprayed or applied with a squeegee. It does not give off toxic fumes during application and is not dependent on the weather. It also offers better performance than hot built-up roofing.
Built Up Roofing Nottingham
What is a built up roof?
Built-up systems are installed by alternating layers of asphalt or tar and supporting fabrics directly onto the roof. You can choose the number of layers (or plies) that are installed. The final layer of a built-up roofing system consists of stone or gravel.
Do flat roofs always leak?
The main reason that flat roofs are more likely to leak is that they are less able to shed water. In other words, they do not allow elements like water to slide off them as easily as steeply sloped roofs do. ... This is why they are also known as low slope roofs
What is a built up flat roof?
A built-up roof, most of the time referred to as BUR, is a time-tested roofing system typically comprised of hot tar and gravel. It is made up of many layers and typically the top layer is where the tar and gravel lie. ... Of all the flat roof options available today, BUR has been around the longest.
What is the difference between built up roofing and modified bitumen?
Modified bitumen expands and contracts without losing its shape. BUR systems are installed through a build-up of layers. A commercial roofing contractor will have alternating layers of roofing felt and bitumen in the form of asphalt, tar or cold-applied adhesive
How do you install built up roofing?
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?
15 to 30 years
Depending on the climate and the specific materials used, built-up roofing has an average life expectancy of 15 to 30 years, but some constructions can last up to 40 years.