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

Flat roof replacement costs $7,399 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 price of this project.

Size of Roof

Calculating the size of your roof can give you a general idea of what a replacement will cost. While approximate, you can measure and multiply the base of one wall with the base of another to get the size of your flat roof.

The values below contain labor costs, but the type of roof you plan on replacing as well as the material it’s made of will also have a large effect on your flat roof replacement cost. 

Type of Roof

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

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.

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 

Material of Roof 

Flat roofs, just like traditional sloped roofs, offer a multitude of material options. Each has its own cost estimate, advantages, and disadvantages. Many look similar so make sure to discuss with your pro which one is best and if you should replace the old flat roof material with the same material, or a different option.

Roofing Professional Costs 

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 

General contractors like to charge project fees, and will charge a similar rate as a roofing professional. There are a number of different ways general contractors charge for their expertise, so read the contract carefully before signing. 

Additional Cost Factors 

You’ll want to factor in additional costs as well, including demolition work and permits.

Demolition and Prep

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. Prep involves removing any debris, mold, or algae, and repairing any damage. 

Permits

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. 

Inspections 

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.

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, there are usually reviews online you can check.  

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.

DIY Flat Roof Replacement vs. Hiring a Pro 

This is too large a job to DIY and there are too many things that 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 a minor issue like a few inches of a bad seal can cause 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 are often made of rubber-like material that is 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).

However, there are some times it makes more sense to replace the entire roof—even considering the cost:

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

• If the repair significantly alters the appearance of the roof. 

• If you can get a good deal on a full replacement. 

• If 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 below options 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. 

• Choose budget-friendly materials. 

• Gather multiple quotes. 

• 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—result in increased value. However, the real question most homeowners have is how much of their investment will be returned. The good thing is that 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. 

Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.