Modified Bitumen
Modified Bitumen

Modified Bitumen

Closely related to the BUR roofing system, Modified Bitumen is a hybrid asphalt-based, two-ply roofing system suitable for commercial buildings with flat or “low-slope” roofs.

Many different application methods are available when it comes to installing SBS modified bitumen roofing systems – the asphalt can be hot-mopped, torch-welded, cold-applied, or self-adhered with membrane sheets.

Modified Bitumen


In a modified bitumen roofing system, the asphalt bitumen is modified with rubber or plastic polymers – usually a polymeric material called Styrene Butadiene Styrene, or SBS. After modification, the SBS is typically reinforced with either polyester or fiberglass.

These alterations enhance the flexibility of the asphalt and enhance its ability to withstand more extreme temperatures.

Whereas BUR is a multi-ply “tar and gravel” roofing system, SBS modified bitumen roofs usually consists of two layers – a base sheet and a cap sheet. Typically, the smoothed surfaced base sheet is self-adhered to the roofing substrate or coverboard, followed by the installation of a granulated cap sheet on top.

Bitumen Roofing


Durable protection against fire, wind, hail, UV, and extreme weather


Insulation properties reduce energy consumption


Requires low-maintenance after installation


Low-slope prevents water from pooling on the surface


Wide variety of application methods available


Reliable protection for 20+ years

Two-ply protection against wind, punctures, & UV.

When selecting the torch-applied method, it’s important to first review local ordinances, fire codes, and building regulations to ensure the use of torches are not prohibited on your roof. These types of installations should only be performed by a fully licensed and trained Certified Roofing Torch Applicator.

Cold-applied and self-adhesive methods are the most popular methods because they tend to provide the highest protection at the least cost, while also producing fewer fumes than the hot-mopped or torch-applied methods.

Modified Bitumen
Modified Bitumen
Modified Bitumen

Different Ways to Apply Modified Bitumen


This method involves spreading melted asphalt across the roof with industrial mops to create an impermeable finish.


This method uses a torch to melt the underside of the asphalt membranes so they stick to the substrate underneath.


 This method sprays a liquid adhesive from an applicator gun which seals the roofing membrane to the substrate.


This method rolls out membrane sheets with adhesive undersides so they stick directly to the roof.

Let us give you peace of mind

Brazos Commercial Roofing has more than 25 years of experience in servicing Modified Bitumen Roofing Systems for businesses in Houston and across Texas. To learn more about which application method is best for your facility, schedule a FREE consultation with a specialist today.


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