What a tar and gravel roof is
A tar and gravel roof, also called a built-up roof or BUR, is several layers of felt mopped together with hot asphalt, finished with a flood coat of asphalt and a layer of gravel pressed into it. The asphalt is the waterproofing. The gravel protects it from the sun. It was the standard flat roof on Albuquerque homes and commercial buildings for decades, and plenty are still up there.
Signs of trouble
- Bare spots where wind and water have moved the gravel and the asphalt is exposed to the sun
- Blisters: soft, raised bubbles where moisture or air is trapped between layers
- Splits and cracks, often in straight lines along the felt
- Gravel piled up in low spots or washed toward canales and drains
- Failed edges where the built-up roof turns up the parapet
- Ponding that stays for days after a storm
What we repair
- Scrape back gravel, cut out blisters and splits, and patch with compatible materials
- Re-flash parapet edges, canales and roof drains
- Seal around vents, skylights and cooler stands
- Re-embed gravel over repaired areas so the patch is protected
Patching a tar and gravel roof takes compatible materials. The wrong sealant on asphalt can shrink, crack or slide off in summer heat.
When repairs stop making sense
If the felts are wet across large areas, the roof is spongy underfoot, or new leaks keep appearing in different places, the roof is at the end of its life. At that point the money goes further on a new roof: often foam over a properly prepared surface, or a tear-off and TPO. See tar and gravel replacement and tar and gravel vs foam vs TPO.
Cost
Spot repairs on a tar and gravel roof commonly run a few hundred dollars to about $2,000, depending on how many areas need work and how hard they are to reach.
Call us for a free look at your roof. You get photos of what we find and written pricing before any work starts.
Common questions
How long does a tar and gravel roof last?
Often 15 to 30 years, depending on how it was built and how well it drains. Many in Albuquerque are older than that and living on repairs.
Can you coat a tar and gravel roof?
Not directly over loose gravel. The gravel has to be removed or the surface prepared first. Often the better path is new foam or a new membrane.
Is the gravel important?
Yes. It shields the asphalt from UV. Bare areas age quickly and are where many leaks start.