Modified Bitumen

Roofing terms · plain-language definition, with its source

Roofing terms · definition

A rolled, polymer-modified asphalt membrane for low-slope roofs, torch- or self-adhered. A common residential flat-roof system.

Source: Wikipedia — Bituminous Waterproofing

Where this comes up on this site

  • Nail Pop

    A fastener backing out and tenting or puncturing a shingle, creating a leak. Common from improper nailing or deck movement.

  • Manufacturer Warranty

    Coverage on the shingles/system from the maker. Enhanced/system warranties require all-matched components and certified-installer registr…

  • Ohio Matching Law

    Ohio guidance that insurers reasonably match repaired/replaced materials so a roof isn't left visibly mismatched after a partial claim.

  • Low-Slope vs. Steep-Slope

    The dividing line (about 3:12) that determines whether shingles can be used or a membrane system is required.

  • Open Valley

    A valley finished with exposed metal flashing down the center — durable and fast-draining, a premium detail.

  • Insulation Baffle

    A chute at the eave keeping insulation from blocking soffit-vent airflow into the attic.

  • Overlay / Re-Cover

    Installing new shingles over one existing layer. Cheaper and faster but hides deck problems, voids some warranties, and code limits it to…

  • Impact-Rated Shingle

    A Class 4 (UL 2218) hail-resistant shingle that may earn an insurance premium discount in hail-prone regions.

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