Modified Bitumen Roofing

Membrane degradation due to exposure to chemicals, oils and UV is a concern with modified bitumen.

Common Issues

Alligatoring – Cracking of a membrane roof producing a pattern similar to an alligator’s hide. Granule loss accelerats this condition unless the membrane is protected by a roof coating.	Seam Failure – Open and unadhered seams are often the caused by improper torch application. They must be repaired immediately while the membrane is still in good condition.	Roof Ponding – Retention of water on a caused by inadequate roof drainage or structural deflection. Water can enter failed seams or punctures and cause leaks.

Asphalt degradation is a growing concern. UV-rays oxidize the surface of the asphalt and produces a chalk-like residue. As plasticizers leach out of the asphalt, a modified bitumen or “mod bit” roof becomes brittle. Cracking and alligatoring inevitably follows, allowing water to penetrate the system causing blisters, and cracks. Seam failure happens next causing leaks.

Leaks in modified bitumen roofs are difficult to isolate and a seamless roof coating system is a cost effective solution. A reflective coating applied within five years of installation can extend the service life of the membrane by 10 or more years.

The surfacing of the sheets is also a maintenance concern. Modified Bitumen sheets are not as sensitive to ultraviolet light as built up roofs but there is still degradation. Studies have indicated that a reflective coating applied within five years of installation can extend the service life of the membrane by 10 or more years.

Learn more about Modified Bitumen Roof Repair or Modified Bitumen Roof Coating.