Understanding the Cost of Bitumen Roofing Materials and Installation
Last Updated: January 06, 2023
Fact Checked By: Ryan Maguire
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A modified bitumen roof (MBR), also known simply as a bitumen roof, is a type of built up roofing system that's designed for installation on a flat or low-slope roof.
Modified bitumen is composed of layers of bitumen that have been blended with synthetic rubberized polymers. Like other forms of built up roofing, modified bitumen roofs offer an economical flat roofing system.
Modified Bitumen Roof Average Costs #
- Bitumen roofs cost approximately $2.50 to $4.00 per square foot installed. For a 1,500 square foot roof, that's a total cost of $3,750 to $6,000.
- When you add in the cost to strip and dispose of the existing roof, then install a new bitumen roof, the cost might be $4 to $8 per square foot (or $6,000 to $12,000 for a 1,500 foot roof).
The actual cost of a bitumen roof depends on the quality of materials used, your location, the complexity of the installation, and other factors.
Bitumen Roofing Example Prices From Completed Projects #
"I had a new modified bitumen roof installed on my small commercial warehouse here in Ohio. For the low-slope 5,000 sq ft roof, the modified bitumen membrane material and installation was $5.50 per sq ft for a total cost of $27,500." - Mark S.
"We went with a modified torch-down roof for our commercial condo building in Colorado that had complex flashing and piping. For the 11,000 sq ft roof, our final installed price was $7 per sq ft including expansive HVAC equipment flashings for $77,000 total." - Olivia P.
"I'm a facilities manager and we needed a durable, long-lasting flat roof solution for our high school building. We chose a premium grade white modified bitumen membrane which cost $10 per sq ft installed for the massive 80,000 sq ft roof. Total job was $800k." - Robert G.
"Our manufacturing facility requires maximum uptime so I wanted leak protection. We had heavy duty smooth modified membrane with heat-welded seams applied to our 75,000 sq ft roof for $6 per sq ft giving us a total modified bitumen roof cost of $450k." - Melissa W.
As shown in these quotes, modified bitumen roofing costs ranged widely from $5 - $10 per sq ft installed depending on product grade, buildings, locations, complexity and more.
An Overview of Modified Bitumen Roofing #
Modified bitumen roofing systems were developed in Europe in the 1960s and first used in the United States in the 1970s. Manufactured in a roll material, MBR membranes contain polymer-modified bitumen with reinforcing plies of fiberglass, polyester, or a combination of the two materials. A modified bitumen roofing system may also have a factory surfacing made from mineral granules, aggregate, metal foil-laminate, or liquid-applied surfacing.
As for the modified bitumen, there are two major polymers used to enhance it:
- APP Polymer: Providing a more plastic-like quality to the asphalt, atactic polypropylene (APP) membranes are usually heat-welded or torch applied.
- SBS Polymer: Styrene-butadiene-styrene (SBS) polymer has a more "rubberized" quality and can be installed with mopped-on hot bitumen, cold adhesive, or a self-adhesive backing.
A bitumen roofing system can be applied as a one, two, or three-ply system, although two-ply is the most common. The system is usually fully adhered.
Reasons to Install Modified Bitumen Roofs #
Although more commonly used for commercial roofing, modified bitumen is perfectly acceptable as a residential flat roofing solution as well. Consider installing it on your home for the following reasons:
- Technology: Polymer-modified bitumen, compared to traditional asphalt, provides increased strength, flexibility, and ultraviolet resistance in addition to better resistance to aging and weathering.
- Flexibility: Modified bitumen roofing membranes, depending on whether they contain glass fiber or polyester plies as reinforcing fabrics, have different characteristics that make them more suitable for certain applications. The same is true of the type of polymer (APP or SBS) used. It's also possible to apply a bitumen roofing system that consists of one or more MB sheets, or is laid down as "hybrid" system made of built-up-roofing felts and MB sheets. Be sure to speak with a contractor about the type of MBR that's right for your home.
- Competitive Life-Cycle Cost: A bitumen roof system can easily last for 10-20 years, especially with the application of a reflective coating within five years of installation. Peak performance, however, depends on quality installation, so be sure to choose a contractor who has extensive experience working with bitumen roofing.
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