Built-up roof repair
A built-up roof (BUR) is layers of roofing felt and hot asphalt or coal tar, usually finished with gravel. It is the classic "tar and gravel" roof on older schools, offices and stores. BUR repairs typically cost $3 to $7 per sq ft of damaged area; a new BUR roof runs $4 to $10 per sq ft and lasts 15 to 30 years.
BUR repair
$3 to $7 per sq ft
Replacement $4 to $10 per sq ft.
Common built-up roof problems
- Blisters, where moisture or air between the plies expands in the sun.
- Splits from building movement or shrinkage, often in long straight lines.
- Bare spots where gravel has washed or blown away, exposing the asphalt.
- Alligatoring (a crazed surface) on older, unsurfaced roofs.
- Failed base flashings at walls and curbs.
What built-up roof repairs typically cost
| Job | Typical price |
|---|---|
| BUR repair Per sq ft of repaired area | $3 to $7 per sq ft |
| Blister repair Cut, dry, re-adhere and cap | $250 to $1,500 |
| Split repair Strip-in with new felts | $200 to $1,500 |
| Alligatoring Resurface the affected area | $250 to $1,250 |
| New BUR roof Installed | $4 to $10 per sq ft |
Typical US prices from published national roofing cost guides, January 2026 editions, read November 2026. Installed, in US dollars, before any local tax. A guide, not a quote.
What a sound built-up roof repair includes
A dry, clean, primed surface
Patches and seams only hold on clean, dry membrane. A roofer who patches over standing water or dirt is selling a callback.
The cause, not just the drip
Water travels under membrane and along deck flutes, so the wet ceiling tile is rarely under the hole. A good repair names where the water got in.
Gravel replaced
The gravel protects the asphalt from sun and hail. After any repair the surfacing should be put back, embedded in a flood coat.
Wet insulation found and dealt with
Wet board loses most of its insulating value and holds water against the deck. Cores or a moisture survey show how far it has spread; badly wet areas are cut out and replaced.
Photos before and after
Dated photos of every repair, and its location on a roof plan, protect your warranty and any insurance claim, and help the next roofer.
Safe access and fall protection
Work near an unprotected edge on a low-slope roof calls for fall protection under OSHA 1926.501: guardrails, safety nets, personal fall arrest or the combinations the rule allows. Ask how the crew will get up and stay safe.
Tar and gravel roof leaking? We will look for a roofer who covers your building.
Ask for a free quoteHow a built-up roof repair usually goes
Find the entry point
The roofer walks the roof, checks the areas above the leak and upslope of it, and may use a moisture meter, infrared scan or cores.
Make it watertight
If water is coming in, a temporary repair first: a compatible patch, sealant or tarp held down so wind cannot lift it.
Permanent repair
The proper detail for the system: a heat-welded patch, taped seam, re-set flashing or a section of new membrane.
Report and photos
Before and after photos, what was found and what to budget for next, so you can decide between repair and replacement with facts.
Questions people ask
What is a built-up roof?
Alternating layers of roofing felt and bitumen (asphalt or coal tar), built up on site and usually topped with gravel. It is one of the oldest commercial roof systems.
Can a tar and gravel roof be repaired?
Yes. The gravel is scraped back, the damaged area is repaired with new felts and bitumen, then the gravel is put back in a flood coat.
How long does a built-up roof last?
Typically 15 to 30 years, depending on the number of plies, the surfacing and maintenance.
Is it worth repairing an old BUR roof?
If the insulation is dry and the problems are local, yes. If cores show wet insulation across the roof, replacement is usually the better spend.
What does a built-up roof repair cost?
About $3 to $7 per sq ft of damaged area.
Where our information comes from
Get the built-up roof repaired
The building ZIP, where to reach you, then a few taps about the roof. About a minute.
This is a free matching service, not a commercial roofer. We look for one who works in your area and tell you their name before anything is shared. Nobody contacts you until you say yes.
Thanks, your enquiry is in.
- We look for a commercial roofer who covers your building and does this kind of work, then email or call to tell you who it is.
- Your details reach that firm only if you say yes.
- They inspect the roof and give you a written price. No marketing from us, ever.