How Much Does Flat Roof Replacement Cost? [2025 Data]

Flat roof replacement costs $7,396 on average, though it can range from a low of $1,200 to a high of $24,000 depending on the roof’s size, style, and material. Flat roofs have many advantages over sloped roofs; a major one is that they’re easier and less expensive to replace. Learn all the factors that contribute to the cost of a flat roof replacement project.

Flat Roof Replacement Cost by Size

Calculating the size of your roof can help you estimate what a replacement will cost. For a rough approximation, measure the length of your house's exterior, then multiply it by the width to get the size of your flat roof. Consider adding a small percentage to account for any overhangs.

Here are estimated costs by roof size—but keep in mind that the type of roof you plan on replacing, as well as the material, greatly affect your flat roof replacement cost:

Flat Roof Replacement Cost by Material

Like traditional sloped roofs, flat roofs offer a multitude of material options. Each has its own cost estimate, advantages, and disadvantages. Many roofing materials look similar, so discuss options with your pro. You should decide whether to replace the old flat roof material with the same material or a different one.

Here’s a breakdown of estimated flat roof replacement costs based on material:

Flat Roof Replacement Cost by Type

There are several types of flat roofs, including cold roofs, warm roofs, and green roofs. The type of flat roof will influence the price you pay for a replacement. 

Here’s how much flat roof replacement might cost based on roof type:

Cold Roof Costs

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 they’re not as energy efficient, and installation can be more complex. You can expect to pay about $4 to $9 per square foot.

Warm Roof Costs

Warm roofs have insulation on top of the roof deck. The vapor barrier goes below the insulation to prevent rot. This option is pricier than cold roofs, but it’s more energy-efficient and often easier to install. These roofs cost around $6 to $11 per square foot.

Flat Roof Replacement Cost by 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. Here’s how the flat roof application type might influence your cost: 

• 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 

Costs for Flat Roof Replacement Pros

Roofers 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. If you’re quoted a fee based on the total project cost, expect the markup to be 20% to 30% of the job. 

General Contractor Costs 

Want to hire a general contractor instead? These pros often have project fees, and their rates are similar to those of a roofing professional. General contractors charge in many different ways, so read the contract carefully before signing.

Additional Flat Roof Replacement Cost Factors 

When planning a flat roof project, you should also factor in additional costs, such as demolition work and permits.

Cost of Demolition and Prep

If your roofing pro bills separately for existing roof removal, 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. Prep involves removing debris, mold, or algae and repairing any damage. 

Permit Costs

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. 

Inspection Costs 

It’s a good idea 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 and $300 for this inspection.

Cost of Warranties 

New roofs should come with manufacturer warranties for the materials. Assuming the materials are the same, choose the purchase with the longest and most thorough warranties. If you have doubts about the warranty, check online reviews.  

Repair Costs for Flat Roofs

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 those for other types of roofs. You can expect to pay an average of $400 to repair minor damage to a flat roof.

DIY Flat Roof Replacement vs. Hiring a Pro 

A flat roof replacement is too complex for a DIY job, as many things can go wrong. While you can save a couple thousand in labor costs, remember that you’re using your own time as well. Most homeowners lack the expertise required for such a job, and even minor issues like a few inches of a bad seal can spell disaster for your home. 

You may be able to work alongside a pro, though. Hire a local flat roofing contractor to avoid improper installation, unnecessary maintenance, or safety risks. Ask if you can learn how to do some of the work while contributing your own time on sections of the job that wouldn’t result in severe consequences if done incorrectly.

Flat Roof Replacement vs. Repair 

Flat roofs are more difficult to repair than sloped roofs because they’re often made of rubber-like material that’s rolled out in large sections. If the issue is small, like a bad seal or physical damage to a small section, a roofing professional could remove and replace that section (or reseal it if the material is in good condition).

That said, it sometimes makes more sense to replace the entire roof, even considering the cost. Here’s when you might choose a flat roof replacement: 

• The repair will cost more than 50% of the replacement. 

• The repair significantly alters the appearance of the roof. 

• You can get a good deal on a full replacement. 

• A warranty or insurance claim will cover a full replacement. 

Tips to Reduce Cost While Replacing a Flat Roof

Replacing your roof is a major investment. Saving money requires some finesse, but it’s possible. Consider some of the options below if you’re looking to save a few dollars:

• Check your insurance. You may have a valid claim that can be covered. 

• Schedule all work in the off-season, when contractors may offer lower rates. 

• Choose budget-friendly roofing materials. 

• Gather multiple quotes to compare the best contractor rates. 

• Consider energy-efficient roofing materials.

Does Replacing a Flat Roof Increase Home Value?

Almost all projects that replace larger pieces of a house—like a roof—increase its value. New roofs are excellent investments, and most homeowners can expect to recoup between 50% and 70% of the cost of a flat roof replacement. 

Therefore, if a homeowner spends $10,000 on a flat roof replacement, they can expect to see $5,000 to $7,000 returned to them in the form of value when they sell the house. Some choose to simply add the repair amount to the total price, and that’s certainly a valid method if you’re selling your home.

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. 

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