11/02/2005

BUR is Better than Before

Economical and durable, asphalt roofing remains a favorite for many facilities

 

Asphalt Roofing and the Future
Asphalt roofs are expected to be the workhorse for commercial buildings into the foreseeable future. Most building designers and owners will continue to take the whole-building approach in roof design and will choose the optimum combination of high performance, cost effectiveness, and energy efficiency when designing their low-slope roofing system. In doing so, they will find flexibility and choice in the selection of roof systems, as well as in a building’s operating equipment. One thing is certain: For the foreseeable future, whenever the roofing system is approached as a whole, there will be a place for asphalt-based BUR products.

 

Built-up roofing (BUR) systems use the redundancy of multiple layers and the proven performance of asphalt to provide long-term durability and excellent water-leak resistance. Asphalt roofing systems provide time-tested performance at a very economical price, making them ideal for both large and small buildings with low-slope roofs. These benefits can be obtained without compromising aesthetics or solar reflectance.

The Washington, D.C.-based Asphalt Roofing Manufacturers Association (ARMA) recommends a “whole-system” approach when evaluating roofing systems for specific applications. Over the years, asphalt roofing manufacturers have adapted their products to changing design needs. The roofing industry continues to respond to the new challenges presented today; as a result, asphalt BUR is better today than ever before.

Staying Power
In many ways, today’s hot-applied bituminous roofing systems are not much different from those installed when ARMA was founded in 1915. A professionally installed, traditional built-up roof is hard to improve upon. A four-ply BUR provides about 280 mils of waterproofing thickness, whereas other systems typically provide 60 mils of thickness (and sometimes less). The increased mass enables BUR to stand up to the forces of nature.

Trends in BUR
Solar reflectance of roofing systems has been receiving greater attention recently. Reflective coatings are just one option in the whole-system building approach. A building owner can enjoy the long-term performance advantage of a traditional asphalt built-up roofing system and have a system that provides environmental benefits as well.

Light-colored gravel is an excellent alternative. Its reflectance is on the order of 40 percent when initially applied. This reflectance, in combination with its thermal mass and self-ventilating capability, is sufficient to reduce roof temperatures and provide significant energy-efficiency performance.

As an alternative to a gravel surface or coated surface, light-colored or metallic-surfaced modified bitumen membranes and BUR cap sheets are available that can increase the reflectance of asphalt BUR. So, if energy efficiency is important to the roofing system, BUR has options that can meet this need.

Whole-System Approach
When the whole-system approach is used to evaluate the performance of roofing systems, some combination of asphalt roofing materials and insulation is usually found to be the best choice, even in cases where reflectance and other energy/environmental concerns are heavily weighted. A traditional asphalt built-up roof with a reflective modified bitumen cap sheet - or a reflective, non-modified glass reinforced mineral surfaced cap sheet combined with a moderate amount of insulation - can sufficiently reduce heat loads to save on air-conditioning costs during the daytime, and provide outstanding roof wind resistance and longevity.

Asphalt BUR can be applied to withstand high-velocity winds as well. High winds produce tremendous stress concentrations that can tear apart a membrane that is not sufficiently attached. Appropriate fasteners closely spaced are used with good success. In high-wind zones, BUR can often be fully adhered to the deck or substrate. Asphalt binds the membrane plies together and adheres the membrane itself strongly to the roof deck or substrate; the substrate itself is often installed with asphalt also. Thus, the whole system can withstand extreme uplift forces because it is evenly distributed over a large area when the roofing system is fully adhered with asphalt.

This column was provided by the Washington, D.C.-based Asphalt Roofing Manufacturers Association
(www.asphaltroofing.org).

 

 

Need portable cooling?

Rent or buy spot coolers from full-service locations nationwide. On call “24/7”. Primary, supplemental or emergency cooling. Atlas Sales & Rentals, Inc., or call (800) 972-6600.

Click here for more info


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.

Need portable cooling?

Rent or buy spot coolers from full-service locations nationwide. On call “24/7”. Primary, supplemental or emergency cooling. Atlas Sales & Rentals, Inc., or call (800) 972-6600.

Click here for more info


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.


 
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