Estimate your built-up roof cost in seconds. This free built-up roof (BUR) cost calculator gives you an instant price for a tar-and-gravel flat roof by system — cap sheet, tar & gravel or heavy-duty — plus roof size, insulation and tear-off, then compare free quotes from licensed local roofers.
*Typical U.S. installed pricing. Enter your roof details for an estimate matched to your home.
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Enter your roof size and options for an instant price range.
Built-up roof quotes vary by system and installer. Our calculator draws on real installation data from across the U.S. so you walk into every conversation informed — and our free quote tool puts vetted local roofers in competition for your job.
Estimates built from thousands of real flat roof installs — by material, roof size and your local labor rates.
Compare licensed, insured flat roofing pros side by side. No pressure, no hidden fees.
See how cap sheet, tar & gravel and heavy-duty built-up roofs compare on price and durability.
Get a realistic flat roof cost estimate in three simple steps — no email or sign-up required. Enter a few details about your roof and see a full price breakdown instantly.
Add the length and width of your flat roof in feet and we calculate the total area automatically. For L-shaped roofs, measure each section and add them together.
Select your membrane — EPDM, TPO, PVC, modified bitumen or built-up — then set tear-off, insulation and roof complexity. Each option adjusts your estimate the way a contractor's quote would.
Instantly see your total price range, cost per square foot and a line-by-line breakdown of materials, labor, tear-off and insulation — then request free quotes to confirm.
Each estimate begins with up-to-date installed pricing for your chosen membrane, then applies the cost drivers that most influence the final figure — tear-off, insulation, and the roof's complexity and access. Results are shown as a range because no two flat roofs are alike: the lower figure reflects a simple, easy-access roof in a lower-cost region, while the higher figure reflects a complex, multi-story roof with premium materials and a full tear-off.
Most projects fall near the middle, which we display as your estimated total. For a firm price, we recommend confirming with a licensed local roofer who can inspect your deck, drainage and existing membrane in person.
Typical installed price per square foot (materials + labor) for a built-up (BUR) tar-and-gravel roof in the U.S. by system. Your final cost also depends on the number of plies, roof size, insulation and tear-off.
| BUR System | Installed $/sq ft | Lifespan | Best For |
|---|---|---|---|
| Smooth / cap sheet | $4 – $7 | 15–20 yrs | Lighter, lower-cost BUR |
| Tar & gravel (3–4 ply) | $5 – $9 | 20–30 yrs | Classic durable flat roof |
| Heavy-duty (5-ply) | $6 – $11 | 25–30 yrs | Maximum durability & traffic |
Ballpark total installed cost by roof area for a mid-range tar-and-gravel (3–4 ply) built-up roof with tear-off and standard insulation. Use the calculator above for a figure matched to your BUR system.
| Roof Size | Typical Example | Low | Average | High |
|---|---|---|---|---|
| 100 sq ft | Small porch / bay | $600 | $900 | $1,500 |
| 300 sq ft | Garage / carport | $1,800 | $2,700 | $4,500 |
| 500 sq ft | Extension / addition | $3,000 | $4,500 | $7,500 |
| 1,000 sq ft | Small home / duplex | $6,000 | $9,000 | $15,000 |
| 1,500 sq ft | Full flat-roof home | $9,000 | $13,500 | $22,500 |
| 2,000 sq ft | Large home / small commercial | $12,000 | $18,000 | $30,000 |
Built-up roofing (BUR) is priced largely by how many plies it has and how it’s surfaced. Here is how the common tar-and-gravel systems compare.
A cap-sheet BUR finishes the built-up layers with a mineral-surfaced top sheet instead of loose gravel. It’s lighter, lower-cost and easier to inspect and repair than a gravel roof.
Its lifespan is a bit shorter than a full gravel-surfaced system, but it’s a practical, economical built-up option.
The classic built-up roof: three to four alternating layers of asphalt (tar) and reinforcing felt, topped with a layer of gravel. The gravel shields the asphalt from UV and adds fire resistance.
It’s heavy and labor-intensive to install, but a well-built tar-and-gravel roof is durable, walkable and long-lasting.
A five-ply built-up roof adds extra layers of asphalt and felt for a thicker, tougher membrane — the most durable BUR, used where the roof sees heavy foot traffic or demanding conditions.
It’s the priciest and heaviest built-up option, but delivers the longest life and best resistance to wear.
The best membrane depends on your climate, budget, roof traffic and how long you plan to stay. Get matched with vetted local pros who can inspect your roof and recommend the right system.
Two flat roofs of the same size can differ by thousands of dollars. These are the factors our calculator accounts for — and the ones your contractor will price.
| Cost factor | How it affects your quote | Price impact |
|---|---|---|
| Material choice | Premium membranes like PVC and TPO cost more per square foot than EPDM or modified bitumen — but often last longer. | High |
| Roof size & shape | Bigger roofs cost more in total but less per square foot. Odd shapes and many penetrations add labor hours. | High |
| Tear-off & disposal | Removing and hauling away the old roof adds roughly $1–$2 / sq ft. Overlays are cheaper, but not always allowed by code. | Medium |
| Insulation & R-value | Adding or upgrading insulation — especially tapered systems for drainage — raises material cost but improves energy performance. | Medium |
| Drainage & ponding | New drains, scuppers or tapered insulation to correct ponding water add cost but protect the roof's lifespan. | Low |
| Access & height | Multi-story roofs, poor access and scaffolding or safety requirements all increase labor charges. | Medium |
| Your location | Local labor rates, permit fees and building codes vary by city and state, moving the total up or down. | Medium |
| Deck repairs | Rotted decking or structural fixes discovered during tear-off are billed on top of the base price. | Varies |
Caught early, some flat roof issues are cheap repairs. Left too long, they mean a full replacement. Watch for these warning signs.
Water that sits for 48+ hours after rain signals drainage failure and accelerates membrane breakdown.
Raised bubbles or blisters mean trapped moisture or air under the membrane — a sign it's failing.
Cracking, splitting or shrinking membrane lets water in and usually can't be patched indefinitely.
Brown ceiling stains, damp patches or a musty smell mean water is already getting inside.
Low or sagging spots point to a saturated deck or structural issue that needs prompt attention.
Most flat roofs last 15–30 years. If yours is near the end of its life, replacement is often smarter than repair.
Tell us about your flat roof project and we'll match you with up to 3 licensed local roofers. Compare prices and pick the best deal — the choice is 100% yours.
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A built-up (tar and gravel) roof costs about $4 to $11 per square foot installed, or roughly $5,000–$12,000 for an average flat roof. The number of plies and the surfacing (cap sheet vs gravel), plus roof size, insulation and tear-off, all affect the price.
A built-up roof is one of the oldest flat-roof systems — three to five alternating layers of asphalt (tar) and reinforcing felt, usually topped with gravel or a cap sheet. It creates a thick, durable, waterproof membrane.
A built-up roof typically lasts 20–30 years. More plies and a gravel surface push it toward the top of that range, while lighter cap-sheet systems last a bit less.
BUR is heavy, durable and walkable, and the gravel adds fire and UV protection, but it’s labor-intensive and heavy. Single-ply membranes like TPO and EPDM are lighter and faster to install — the right choice depends on the building and budget.
It’s heavy (the structure must support it), messy and labor-intensive to install, and the gravel can clog drains and make leaks harder to trace. But it’s very durable and time-tested.
Yes — one of BUR’s advantages is that it stands up to foot traffic better than most membranes, which is why it’s common on roofs with rooftop equipment or regular access.
It gives a data-based estimate using up-to-date pricing by BUR system, roof size and options — ideal for budgeting. For an exact price, get free quotes from licensed local roofers who can inspect your roof.
Wherever your flat roof is, our free tool connects you with licensed, insured roofing contractors near you. We match homeowners with vetted local pros in every major U.S. metro.