What these roofs are
Built-up (BUR)
Layers of roofing felt and hot asphalt, often topped with gravel. Common on older flat roofs.
Modified bitumen
Rolled sheets of asphalt with rubber or plastic modifiers, torched or adhered, often with a granule surface.
How they age
- The surface dries out, cracks and alligators in the sun
- Seams and laps open up
- Blisters form where moisture is trapped
- Flashings at walls and edges pull away
- Granules wear off, exposing asphalt to UV
Restoring with a coating
- Remove loose gravel and debris
- Cut and repair blisters; check for wet insulation
- Seal seams and flashings with fabric and mastic or coating
- Prime if needed to prevent asphalt bleed-through
- Apply a full elastomeric or silicone topcoat
Foam as an option
When an old built-up roof is dry but rough, spraying a layer of foam over it and then coating can add insulation and slope. We'll show you the options. Coating or new membrane?
Call (505) 257-2289 to have your older flat roof evaluated.
Common questions
Can you coat over gravel?
Loose gravel is removed first. The coating needs a clean, solid surface.
Why do asphalt roofs need a primer?
Some asphalt surfaces bleed oils into the coating and stain it. A primer blocks that.
How do you know if the roof is wet underneath?
By probing, checking for soft areas and taking small cores when needed.