Residential · Commercial · Multifamily Serving Seattle & Greater Seattle
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modified bitumen roofing Seattle

Modified Bitumen Roofing

Modified bitumen systems use asphalt-based membranes engineered for low-slope roofing. They are encountered on many existing commercial and multifamily buildings.

Where This System Fits

Modified bitumen can serve low-slope roof areas where the designed assembly, substrate and detailing are appropriate.

What We Evaluate Before Installation

We evaluate membrane condition, laps, flashing, penetrations, drainage, surfacing, substrate and previous repairs.

Installation Details Matter

The material name alone does not determine performance. Edges, transitions, penetrations, flashings, drainage and substrate conditions must be compatible with the selected system and installed as a complete assembly.

Repair or Replacement

A localized defect may be repairable when the surrounding system is in serviceable condition and compatible repair materials are available. Widespread deterioration, repeated leaks or substrate problems may justify replacement.

Important Considerations

Installation methods vary by product and assembly. Repairs should be compatible with the existing membrane, and open flame methods must never be assumed appropriate for every building or project condition.

Request an evaluation to determine whether this roofing system fits your building.

Request a Roofing Evaluation