How Much Does Flat Roof Replacement Cost? [2024 Data]
Normal range: $3,255 - $11,127
U.S. homeowners spend $7,182 on average to replace a flat roof, with costs ranging between $3,255 and $11,127, depending on the roof size, style, and materials used.
If you need to replace your flat roof, expect to pay between $3,255 and $11,127, with an average cost of $7,182. Roofing replacement cost is calculated by the square foot and can vary based on materials, location, and roof type. Learn how these factors affect pricing and what to budget for your flat roof replacement.
- Average
- $7,182
- Low end
- $1,200
- high end
- $23,000
Flat Roof Replacement Cost Factors
If something damages the roof beyond repair, you’ll need to hire a roofing contractor to get it replaced. You can expect the cost of flat roof replacement to range between $4 and $14 per square foot for materials and labor. Consider these additional cost factors.
Size of Roof
You can calculate your roof size to get an idea of your project’s costs. For basic rectangular-shaped houses, you can multiply the length and width of your home. If your home isn’t a simple rectangular shape, you can calculate the square footage by sectioning out your roof.
For example, you may have a home that’s a “U” shape. Calculate the roof sizes of the two long sections and the roof size of the one short section. You can add up these three sections to get your approximate square footage.
| Roof Size (Square Feet) | Average Price Range |
|---|---|
| 1,000 | $4,000–$14,000 |
| 1,500 | $6,000–$21,000 |
| 2,000 | $8,000–$28,000 |
| 2,500 | $10,000–$35,000 |
| 3,000 | $12,000–$42,000 |
Type
Most roofs are either cold or warm, although there are other options available to fit all of your needs. Here are the roof replacement costs you can expect depending on the roof type.
| Roof Type | Average Price (Per Sq. Ft.) |
|---|---|
| Cold | $4–$9 |
| Warm | $6–$11 |
| Inverted | $4–$9 |
| Hybrid | $4–$11 |
| Curved | $8–$15 |
| Tapered | $7–$10 |
| Green | $10–$35 |
Application Method
Depending on the roof type you choose, you’ll have different application methods. The most common application methods for flat roofs are ballasted, fastened, and fully adhered.
Ballasted roofs: $1.50 to $2 per square foot
Fastened attachment method: $2 to $3 per square foot
Fully-adhered method: $2.75 to $3.50 per square foot
Sealing the Surface
To simplify the maintenance process, apply a sealant or coating to your newly installed flat roof. This adds an extra layer of waterproofing and can increase fire resistance and overall durability. The quality of a coating can vary quite a bit—it's not always a long-term solution, but with the right product, it can be. Of course, it will also increase the cost of your project. Roof coating costs an average of $500 to $2,300.
Ventilation and Roof Drains
Flat roofs are, well, flat, so having a good drainage setup is an absolute must. You may already have a decent drainage system if you’ve been living under a flat roof, but if you need to have drains or gutters installed or have some pre-existing drains rerouted, you’ll pay $600 to $1,000.
Ventilation is also extremely important, as some flat roof materials can absorb heat, which is then released into your home. Installing a single roof vent costs $300 to $650 on average.
Roof Removal
If your roofing pro bills separately for roof removal, prepare to budget for this service on top of your roof replacement costs. Roof removal costs about $1 to $5 per square foot or an average of $1,000 to $1,500.
One of the advantages of flat roofing is that you can overlay the existing roof instead of tearing it off. But if you have rotten decking that needs to be repaired, you might not discover it if you do an overlay. Additional layers do add R-value to your roof, so you’ll need to make sure that the structure itself can handle the additional weight of another layer. Your roofing contractor should be able to discuss with you if a layover is a viable option.
Permits and Inspections
Depending on where you live, you may need to pay for a building permit to replace your roof. These permits cost between $250 and $600, though this price increases for roofs larger than 1,000 square feet.
Additionally, you may want to hire a professional to conduct a final inspection after the roof has been replaced. This will ensure that the contractor did good work. Expect to pay between $120 to $300 for this inspection.
“A good indicator that the roof needs to be replaced and done by a professional is evidence of missing shingles or other materials. If the roof is beginning to lose shingles during major storms, then it is likely time to have it replaced rather than making repairs.”
– Korey Gregory, Construction Supervisor at ASAP Restoration LLC in Tempe, AZ
Permits and Inspections
Depending on where you live, you may need to pay for a building permit to replace your roof. These permits cost between $250 and $600, though this price increases for roofs larger than 1,000 square feet.
Additionally, you may want to hire a professional to conduct a final inspection after the roof has been replaced. This will ensure that the contractor did good work. Expect to pay between $120 to $300 for this inspection.
Location
Where you live can affect the cost of replacing your flat roof. High-cost-of-living areas will have overall higher labor and material costs than lower-cost-of-living areas. Prices may also increase if you live in an area that is difficult to access or if materials need to be shipped from far away.
Roof Accessibility
A difficult-to-access roof will affect replacement costs. A roofing contractor may need to set up scaffolding or use special equipment to safely access your roof, and these additional steps will add extra labor, material, or equipment costs to the price of your roof.
Labor
Roofers typically charge $3 to $7 per square foot for labor, and a flat roof will take around five days of work to complete, depending on the size and complexity of the job. Some roofing materials, such as built-up tar, are more time-consuming to install, so this will impact the overall cost of labor.
Cost to Replace a Flat Roof by Material
There are many types of roofing materials to work with, each with its own cost estimates, advantages, and disadvantages.
| Flat Roof Material | Average Cost (Per Sq. Ft.) |
|---|---|
| Fiberglass | $4–$6 |
| Rubber | $4–$13 |
| Thermoplastic Polyolefin (TPO) | $4–$14 |
| EPDM | $5–$13 |
| Built-Up Tar | $4–$10 |
| GRP | $4–$6 |
| Modified Bitumen | $4–$8 |
Fiberglass: Fiberglass is not as durable as some other materials, so annual inspections are necessary, but it has a lifespan of 25 to 50 years.
Rubber: Rubber flat roofs are highly resistant to warm weather and solar rays and can last 25 to 50 years if properly cared for.
Thermoplastic Polyolefin: Thermoplastic polyolefin (TPO) is a single-ply system that lasts between 20 and 25 years and can generally handle ponding water for up to 72 hours.
EPDM: This is a roofing material made from oil and natural gas byproducts. It is easy to install, which saves money upfront but tends to fail after 10 to 15 years of use.
Built-up tar: Tar is extremely resistant to fire and does not require too much maintenance. It also lasts about 30 years, but most insurance policies won’t cover it.
Glass-reinforced polyester: This material is a blend of plastic and fiberglass with increased durability and increased resistance to the elements. They can be tricky to install, as the contractor will have to wait for a string of dry days.
Modified bitumen: This material is easy to install and fully recyclable, making it a desirable choice for modern homeowners. Modified bitumen is not exceptionally water-resistant and will need replacement after 10 to 20 years.
Flat Roof Replacement Cost by Type
Flat roofs are not all the same—they’re available in various designs and types, each with its own replacement costs. The roof’s construction, insulation location, types of material, and installation method will all affect the replacement cost.
Cold
Cold roofs have insulation inside the joists or rafters. The area above the insulation is ventilated, most commonly with soffit vents. These roofs are less expensive than warm roofs but are less energy efficient and are more complex to install. You can expect to pay about $4 to $9 per square foot.
Warm
Warm roofs have insulation on top of the roof deck. The vapor barrier goes below the insulation to prevent rot. This option is more expensive than cold roofs, but it’s more energy-efficient and easier to install. These roofs will run you around $6 to $11 per square foot.
Inverted
Inverted roofs have a waterproofing layer on top of the deck, which is usually a liquid membrane. The insulation goes on top, and it’s secured with gravel ballast or concrete pavers. It’s hardy against extreme weather and harsh UV rays. Inverted roofs average $4 to $9 per square foot.
Hybrid
Hybrid roofs have insulation both above and below the deck, which makes them extra durable against severe weather. However, it’s easier for condensation to build up, so it’s not recommended for areas with high humidity or spaces with high occupancies. These roofs cost about $4 to $11 per square foot.
Curved
Curved, flat roofs offer a visual appeal that is both sleek and modern. These are typically custom-designed, so you’ll get exactly what you’re looking for. It comes at a higher price point than most other roof types, ranging between $8 and $15 per square foot.
Tapered
In areas with high amounts of rainfall, you may go with a tapered roof. A tapered, flat roof is a good way to avoid water ponding on top, which can eventually cause water damage and even leaks. Tapered roofs average $7 to $10 per square foot.
Keep in mind that a well-designed and installed flat roof should drain properly, as long as your roof is clear of debris, like leaves, and you have clean gutters. Even so, the tapered design can be a good investment if you’re looking for something a little easier to maintain.
Green
A green roof is the most costly one on this list, ranging between $10 and $35 per square foot. However, if a living roof is the roof of your dreams, there’s nothing else like it. Typically, you’ll see green roofs with small succulents, moss, grass, and even small flowers. You can also get green roofs with small bushes and trees.
These roofs are environmentally friendly and can help improve a roof’s drainage. However, green roofs are heavier than other types, and they’ll require more maintenance.
Ongoing Flat Roof Replacement Costs
Account for repair and maintenance costs in your roofing budget so you can keep your roof in great shape.
Repairs
Flat roofs can be damaged by debris, foot traffic, excess weight from ice or snow, or high heat and UV exposure. Flat roof repairs are often less expensive than for other types of roofs. You can expect to pay an average of $400 to repair minor damage to a flat roof.
Maintenance
Regular flat roof maintenance will help extend the life of your roof and prevent leaks and other damage. Perform periodic inspections to check for damage and clear debris off the roof’s surface. Regular gutter cleaning is an important part of roof maintenance. If you aren’t comfortable climbing a ladder to clear your gutters and downspouts, a professional gutter cleaning will cost between $120 and $235.
DIY vs. Hiring a Pro to Replace a Flat Roof
Replacing a roof is a job that’s best left to the pros. Hire a local flat roofing contractor to avoid improper installation, unnecessary maintenance, or safety risks. Obtain quotes from at least three roofing pros so you can get an idea of the average cost where you live.
If you decide to go the DIY route, your costs will be for materials only, about $1 to $7 per square foot for materials. This includes roofing materials, drainage systems, and sealant. You’ll also need to get a roofing permit, so check your local building codes before getting started.
How to Save Money on Roof Replacement Costs
Replacing your roof is a major investment, but you can save some money on replacement costs.
File an insurance claim: Depending on the reason for the replacement, your insurance may cover some or all of the replacement costs. Remember that filing a claim can increase your insurance premium.
Off-season scheduling: In some areas, roofers may offer discounted rates during the colder seasons if conditions are safe to work in.
Choose a budget-friendly material: Choosing a less expensive material to replace your roof can also save you money, but thoroughly research the material and consult with your roofer to be sure the material you choose is suitable for your needs.
How Angi Gets Its Cost Data
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We’ve surveyed thousands of real Angi customers about their project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
Want to help us improve our cost data? Send us a recent project quote to costquotes@angi.com. Quotes and personal information will not be shared publicly.
Frequently Asked Questions
Replacing a flat roof is a significant investment, so you should take some time before deciding on a pro. Do all the research you can via the company’s official website, any social media accounts, and by checking with the Better Business Bureau.
Don’t be afraid to reach out to the contractor’s previous clients for anecdotal information. Finally, give them a call and have some good questions to ask the roofers prepared ahead of time. A qualified professional will answer them with ease.
Many contractors offer extended roof warranties that go beyond the scope of the warranty offered by the materials manufacturer. Should you buy one? This depends on how long the coverage lasts and the cost of the warranty itself.
You should also check on the specific coverage offered by the extended warranty, as some may exclude common maintenance and repair tasks.
You can if the damage is not extensive enough to warrant a full replacement. Most contractors will perform a free inspection before giving you a quote, so you may just need some minor repairs. Patching small tears and performing other repair jobs cost $300 to $600, though larger overhauls cost $1,000 or more.
Flat roofs can last up to 20 years if properly maintained. You can increase the life span of your flat roof by performing maintenance tasks or hiring a pro to handle them for you. Maintenance tasks include sweeping leaves and dirt, keeping drains clear, inspecting for cracks and punctures, and recoating as needed.
Whether or not your homeowner’s insurance will cover your flat roof replacement depends on several factors. First, you need to check your policy to see what's covered. Generally, policies don't cover replacement due to normal wear and tear or if the need for a replacement is due to lack of maintenance. On the other hand, policies often cover replacements due to accidents or weather events.