Built-up roofing, also known as BUR, is one of the most commonly utilized roofing systems for flat roof commercial buildings. BUR is a roofing method that has been in use for well over a century, and it provides excellent waterproofing protection due to the use of coal tar and bitumen.
A built-up roofing system is typically constructed of alternating layers of reinforcing material and bitumen, covered with a finishing layer of aggregate material, such as gravel or small stones.
First, a base sheet is fastened to the roof’s insulation or cover board. A layer of bitumen is then applied to the base sheet which binds with the next layer of reinforcing felt, also referred to as a ply sheet. Ply sheets are heavy-duty reinforcing fabrics strengthened with either organic material or fiberglass. Multiple coatings of bitumen and felt are applied, and after the desired number of layers have been placed, a mineral-reinforced cap sheet or aggregate material is used for the top layer. There are three main types of BUR systems:
Ballasted Bitumen Built-Up
With this type of BUR system, fasteners or anchors aren’t used to secure the roofing membrane; larger stones are used rather than small granules to weigh the layers down onto the roof deck and keep them in place.
In this method, hot bitumen is used to bind together the layers of roofing material.
This type of BUR system uses an unheated water or solvent-based adhesive that can be sprayed or spread on to the layers of ply material. The cold-applied adhesive acts just like the hot bitumen to bind the ply material together.
Longevity of BUR Systems
A built-up roofing system is known to have an average lifespan of between 15-30 years, but can last up to 40 years depending on the construction and frequency of scheduled maintenance.
Importance of Regular Commercial Roof Maintenance
According to studies conducted by the U.S. Army Corps of Engineers and the American Institute of Architects, an effective roof maintenance program may reduce commercial roof leaks by up to 70 percent and fully double your roof’s life expectancy.
That’s why TEMA Roofing Services places such high importance on an effective roof asset management program. TEMA’s commercial Roof Asset Management program offers a wide range of services designed to ensure that your investment lasts and that warranties remain intact, no matter the type of roofing system you have
Created from more than 20 years of commercial roof maintenance experience, TEMA’s Roof Asset Management program delivers the most comprehensive service:
- Around the clock roof leak response
- Custom-designed preventative maintenance programs for every roof in your asset portfolio
- Cloud-based client portal that stores all roof asset information
- Redundant and secure server for data storage and backup
- A team of commercial roofing professionals with more than a century of combined experience to be your go-to contractor and advocate
Built-up roofing typically holds up better in warmer climates than colder ones, and this system’s lifespan is relatively comparable to asphalt shingles, which also have an expected life of 15 to 30 years, depending on their quality.
Is a Built-Up Roofing System the Right Choice for Your Building?
When is a BUR system the best choice for your commercial building? In the end, it depends on what you are trying to achieve. Sure, built-up roofing has its advantages and disadvantages, but it’s a widely popular option for large commercial buildings and highrises around the world.
The first advantage is that a built-up roof has incredible durability: adverse weather conditions, such as high winds and hail, don’t have the potential to do as much damage to a built-up roof as they would to other types of roofing (like single-ply roofing). Hail and debris are dispersed by the aggregate layer so damage can’t reach the substrate, and these systems can also withstand more foot traffic than other roof types due to that top aggregate layer.
Second, a built-up roof is known to be energy efficient. The top layer of aggregate material provides protection to the bitumen from UV rays, helping to keep the building’s interior cool during hot weather, and reducing utility usage and energy costs. It also has high reflective qualities (when a reflective coating is utilized), helping to save energy costs and keep inside temperatures consistent.
A third great quality of built-up roofing is that it’s fire-resistant. Bitumen roofing combined with the aggregate layer on top serve to make a roof highly resistant to fire, provided it is properly inspected and maintained.
Considering BUR Roofing?
A BUR system is a great choice for a large commercial building or structures with a low-slope roof or flat roof. It’s got a number of money-saving advantages and is made using time-tested materials and technology. As always, though, it’s important to work with a professional commercial roofing contractor you trust!
When you’re ready to learn more about built-up roofing, and whether or not it’s the right choice for your commercial building, contact TEMA Roofing, your trusted leader in the commercial roofing industry. We have decades of experience in commercial roof installation, and are always ready for your roofing project!