True Cost Guide Roofing Install a Flat Roof

How Much Does a Flat Roof Replacement Cost in 2025?

Typical Range:

$3,309 - $11,493

Cost data is based on actual project costs as reported by 1,894 HomeAdvisor members. Embed this data

How We Get This Data

Homeowners use HomeAdvisor to find pros for home projects.

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When their projects are done, they fill out a short cost survey.

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We compile the data and report costs back to you.

Updated December 7, 2024

Written by HomeAdvisor.

Highlights

Flat roof replacement averages $7,401, ranging between $3,309 and $11,493.
Roofing contractors usually charge about $3 to $7 per square foot.
Costs vary depending on roof type, drainage requirements, labor rates, and materials.
Fiberglass and polyurethane represent some of the lowest material costs.
Premium materials, specialized design, and other factors can drive costs higher.

Replacing a flat roof averages $7,401, with most homeowners paying between $3,309 and $11,493. Materials and labor add up to $4 to $15 per square foot. Flat roof replacement costs vary depending on the roof type, drainage requirements, labor rates, and the type of roofing materials.

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National Average	$7,401
Typical Range	$3,309 - $11,493
Low End - High End	$1,200 - $24,000

Cost data is based on actual project costs as reported by 1,894 HomeAdvisor members.

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Flat Roof Replacement Cost Factors

Roof size, type, design, labor rates, and other variables factor into your final flat roof replacement costs.

Cost per Square Foot

Flat roof replacement typically costs $4 to $15 per square foot for labor and materials. Some roofing contractors measure roofs in squares—which is 100 square feet—and charge $400 to $1,500 per square.

The cost per square foot varies depending on the materials used, your location, labor rates, and other project specifics. Low-end costs usually represent basic to standard materials and moderate labor requirements, while high-cost projects reflect premium roofing materials and complex installations.

Flat roofs don’t have slopes like other styles, so the size of the roof closely reflects the square footage of the house’s level below. Flat roofs usually involve a single, continuous layer of material with less labor-intensive framing.

Square Footage	Average Cost Range
500	$2,000–$7,500
1,000	$4,000–$15,000
1,250	$5,000–$18,750
1,500	$6,000–$22,500
1,750	$7,000–$26,250
2,000	$8,000–$30,000
2,500	$10,000–$37,500
3,000	$12,000–$45,000

Roof Type

Flat roofs come in several variations in design, performance, and features. Each type carries its own respective costs. Some features are meant to improve energy efficiency or drainage by slightly manipulating the otherwise flat design or adjusting the insulation. Others, such as curved flat roofs, are mainly decorative and intended as an interesting architectural component.

Roof Type	Features/Characteristics	Cost per Sq. Ft.
Cold	Basic design and less insulation	$4–$9
Warm	Insulation above roof deck for energy efficiency	$6–$11
Inverted	Insulation above membrane	$4–$9
Hybrid/compact	Combines warm and cold roof engineering	$4–$11
Curved	Curved design with flat roof panels	$8–$15
Tapered	Slight slope to improve drainage	$7–$10
Green	Vegetation planted over a waterproof system	$10–$35

Drainage

Installing or rerouting a flat roof drainage system costs $600 to $1,000. Since flat roofs have minimal or no slope, a drainage system is necessary to direct water away, avoid rooftop pooling, and prevent seepage down the sides of your home and foundation.

Sealant

Sealing a flat roof costs $500 to $2,500, depending on type and application. This process involves adding a layer of acrylic, silicone, or other sealant formulas to the top roofing layer, making it more resistant to water and weather damage. Chimneys, skylights, and vents also need flashing to prevent water leaks. Installing flashing costs anywhere from $500 to $1,000.

Labor

Hiring a local roofing contractor to install a flat roof costs about $3 to $7 per square foot or about 20% to 30% of the total project cost. Most estimates include removing and disposing of old roofing. If they don’t, plan for $1,000 to $3,000 for removal and $500 to $1,500 for disposal.

Expect to pay more for labor for replacements with complex elements. For example, a simple flat roof doesn’t usually require advanced skills beyond basic roofing, but specialized flat roofs may require more experience, crew members, and overall time.

Difficult roof access requiring extra time, safety equipment, and scaffolding also creates extra labor costs. Some roof replacements necessitate additional site prep, such as mold remediation or structural repairs.

Permits and Inspections

Permits and inspections are typically required for any project that modifies your home’s main structures, including the roof. Obtaining a permit for roof replacement costs $100 to $600, depending on your municipality. Permit costs usually cover roof inspections.

New Flat Roof Costs by Material

Installed, flat roofs cost anywhere from $4 to $30. At the higher end of the range, premium roofing materials offer better structural integrity, longevity, and weather resistance over low-end types, as well as a luxury aesthetic. Even so, certain materials are affordable, visually appealing, and durable.

Material	Price per Sq. Ft. (Installed)	Average Price per Sq. Ft. (Installed)
Fiberglass	$4–$6	$5
Polyurethane	$4–$7	$5.50
Single-ply membrane	$4–$7	$5.50
Concrete	$4–$8	$6
Modified bitumen	$4–$8	$6
Built-up tar	$4–$10	$7
Rubber	$4–$13	$8.50
TPO	$4–$14	$8.75
Metal	$4–$30	$17

Fiberglass

Fiberglass—also known as glass-reinforced polyester (GRP)—flat roofs average $5 per square foot or $500 per square. Fiberglass flat roofs are usually double-layered for added strength and durability, and they last 20 years or more.

This budget-friendly material is lightweight and fire- and weather-resistant. Fiberglass roofs aren't recommended for large structures because they're prone to ponding across large areas, which strains the roof and risks cracking and leaking.

Polyurethane

Most homeowners pay $5.50 per square foot or $550 per square for polyurethane roofing. Polyurethane roofing, also known as SPF, can last for up to 50 years with proper maintenance. This liquid roofing material expands into a dense, waterproof foam, and its longevity, energy efficiency, and minimal upkeep make it a popular option. Polyurethane requires multiple layers for thorough waterproofing, which increases costs.

Single-Ply Membrane

Single-ply membrane roofs average $5.50 per square foot or between $4 and $7 per square foot. Higher costs within this range typically represent higher-quality materials with seamless engineering, which reduces the risk of weak points and water leaks.

A roof installer heats and stretches PVC, plastic, rubber, or EPDM, then fits and adheres it across your roof with a solvent or bitumen or by melting the material. Lasting 40 years or more, single-ply membrane roofs are energy-efficient and popular among homeowners.

Concrete

Concrete flat roofs cost $6 per square foot, with most homeowners paying between $4 and $8 per square foot. These highly durable roofs can last for 50 years or more. They're weather- and fire-resistant and require minimal maintenance. Labor costs may be higher for concrete roof replacement since it involves moving and installing heavy materials. Some homes may require structural modifications to accommodate the added weight.

Modified Bitumen

Modified bitumen roofs cost around $6 per square foot, ranging from $4 to $8 per square foot. This flat roofing type is notable for its light- and heat-reflective hue and a 30-year lifespan. Modified bitumen requires skilled professional installation, as neglecting material seams can cause weak points and compromise your roof’s integrity.

Built-Up Tar

Expect to pay around $7 per square foot or $4 to $10 per square foot to install a built-up tar flat roof. Made from multiple layers of felt and asphalt, this type of roof is fire-resistant, easy to maintain, and long-lasting.

Rubber

Rubber flat roofs, also known as ethylene propylene diene monomer (EPDM), cost $4 to $13 per square foot and resist damage from the sun, heavy snow, wind, and hail.

TPO

Roofs made from TPO, or thermoplastic polyolefin, average $8.75 and range from $4 to $15 per square foot. A type of modified rubber, TPO requires minimal maintenance, watertight sealing, and a long lifespan. It’s also known for energy efficiency, resistance to UV light and chemical degradation, and reflective qualities.

Metal

Metal flat roofs average $17 per square foot, but you can pay anywhere from $4 to $30 per square foot. Low-cost metal roofs, such as corrugated tin, represent the lower-end costs, while steel and aluminum carry mid-range costs. Copper is a premium type of metal roof that offers superior aesthetic appeal and longevity over other metals.

Flat Roof Replacement vs. Repair

Deciding between flat roof replacement or repair depends on the roof’s general condition, damage severity, age, and the cost of repairs. Depending on the materials used, repairs for flat roofs average $400, and repairing isolated sections of leaks, cracks in seams or joints, and other damage can be a cost-effective alternative to replacement.

If your roof has widespread damage, such as multiple leaks across different areas, issues with underlying layers, or significant overall wear, replacement is potentially a more effective solution than repair. This is especially true if your current roof is approaching the end of its expected lifespan. Replacement also provides an opportunity for aesthetic and energy-efficient upgrades.

Does Replacing a Flat Roof Increase Home Value?

Replacing a flat roof can increase your home’s value, with the actual return on investment depending on the roofing materials and local real estate market conditions. If your current roof is relatively new and in good condition, a new roof may have limited additional value. Otherwise, roof replacement comes with several advantages that appeal to potential homebuyers, such as:

Improved curb appeal
Enhanced energy efficiency
Reduced risk of leaks and water damage
Building code compliance
Lower home insurance premiums

Budgeting for a Flat Roof Replacement

Replacing a flat roof is a major investment, but these budgeting strategies can manage your costs and ensure the quality of your project:

Get multiple estimates detailing pricing for materials, demolition, disposal, warranties, and other services.
Choose roofing materials that balance affordability, function, and visual appeal.
Research tax rebates or other incentives for energy-efficient roof installations.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. We surveyed thousands of real 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.

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FAQs

How do I maintain a flat roof?

Sealant is among the main strategies for maintaining and protecting your roof. Sealing a roof costs $500 to $2,400, and it creates a thick barrier that prevents water from infiltrating your home’s structures. Otherwise, cleaning the gutters and surface at least every six months and periodically inspecting flashing can help keep your roof in good condition.

How often should I clean my roof drainage system?

Clear the gutters after storms or at least every six months. Homes with many pine trees nearby may need their gutters cleaned more frequently, about every four months. Sweep debris off the roof periodically and schedule professional roof cleaning as needed. Flat roofs are more likely to collect leaves, dirt, and other debris that can accumulate in piles and trap standing water, resulting in leaks.

How much do flat roof repairs cost?

Patching small tears and other minor flat roof repairs cost $300 to $600. Repairing storm damage, rerouting drains, and other major overhauls could cost over $1,000. Regularly inspect your roof for tears, holes, and leaks, and promptly address these issues to minimize further damage.

What are the advantages and disadvantages of a flat roof?

Flat roofs offer several advantages, starting with a relatively low installation cost compared to other styles, as they require fewer materials and labor. Some homeowners use their flat roofs as outdoor living spaces, installing rooftop gardens, gathering areas, storage, or solar panels. Flat roofs also accommodate capable insulation systems to improve thermal efficiency and lower energy consumption.