5 Tar & Gravel Roof Problems and How to Prevent Them

Gravel built-up roofing (BUR) systems are durable but develop specific problems. Here are the 5 most common issues and how to address them.

1. Blistering

Air or moisture trapped between plies causes bubbles or blisters to form. Prevention: proper installation with adequate ventilation. Solution: small blisters can be left alone; large or rupturing blisters should be cut, dried, and patched. Widespread blistering indicates a system-wide issue requiring restoration.

2. Alligatoring

The surface asphalt oxidizes and cracks in a pattern resembling alligator skin, indicating advanced UV degradation. Prevention: annual maintenance and prompt repair of granule loss. Solution: coating restoration can seal alligatored surfaces and extend system life.

3. Gravel Erosion

Gravel washes or blows off over time, exposing the underlying felt to UV. Prevention: periodic gravel redistribution or addition. Solution: if significant felt exposure has occurred, restoration or replacement may be needed.

4. Ponding Water

Low spots accumulate water, accelerating deterioration in those areas. Prevention: address drainage at installation. Solution: spray foam after gravel removal can build slope to correct ponding.

5. Membrane Delamination

Plies of the BUR system separate, creating voids for water infiltration. Prevention: proper installation and dry substrate. Solution: if delamination is widespread, full restoration or replacement is required.