How Much Will a Flat Roof Cost?

There was a time when flat roofs were only seen in commercial spaces, but that’s not the case anymore. Many homeowners opt for flat roofs to maximize interior space and reduce installation costs.

Flat roof repair

If you believe it’s time to have a new roof installed, you’re probably wondering how much you will spend. While there are some variables to consider, you can look at national averages to get a good idea of flat roofing costs.

What is a Flat Roof?

The flat roof is one of the oldest and most simplistic roof styles in the world of homebuilding. While the sleek, straight, clean lines associated with flat roofs are often associated with modern architecture, the use of flat roofs is anything but modern. Hundreds of years ago, people building their own homes typically put a flat roof on the house because it was easier for one person to construct it. While there are many different roof types out there, flat roofs have been one of the most trusted roofing types in history.

While it’s easy to assume that a flat roof is just a flat roof, some numbers define what constitutes a flat roof. According to the International Building Code, a roof with a minimum pitch of 1/4-to-12 is considered a flat roof.

How Much Does Flat Roof Repair Cost?

If your flat roof is damaged but doesn’t need to be replaced you can save some money by opting for a simple repair. Based on national averages, flat roof repair costs around $700. The lowest price for flat roof repair is around $300, while the highest cost is closer to $1,100.

Size is the determining factor when it comes to cost. The national average flat roof repair cost for a 25-square-foot section is $163. The national average for a 500-square-foot repair is $3,250. The prices for repairs that fall within that range vary.

Different Types of Flat Roof Repair

When you look at your roof, you just see the finished product. You may not realize that multiple layers were installed in different steps. Although some flat roofs are topped with a single waterproof membrane made of PVC or thermoplastic olefin, others are comprised of three layers:

  • Modified Bitumen
  • Cap Sheet
  • Roll Roofing (aka mineral surface roll or MSR)

Since flat roofs are easier for contractors to move around on, the repairs cost less than roofs with a steeper pitch.

There are five common types of flat roof repairs. Here’s a look at how much each costs:

  • Fixing Loose Seams: $200 to $500
  • Drip Edge Repair: $200 to $450
  • EPDM or Modified Bitumen Membrane Repair: $250 to $1,650
  • Large Sags in Flat Roofing Materials: $800 to $2,200
  • Removing the Entire Flat Roof: $1,600 to $5,500

Aside from the type of repair, the roofing material will also impact costs. For instance, the cost of fiberglass repair falls between $5 and $7 per square foot, while the cost of repair for black EPDM is between $6 and $14 on average.

How Much Does it Cost to Replace a Flat Roof

If your roof is beyond repair, your contractor will recommend that you have a new flat roof installed. There are three factors that roofing contractors will use to determine the cost of a roof:

  1. The size of the job
  2. The type of material
  3. Labor costs

When contractors are quoting you a price, they calculate how many hours they expect the job to take and multiply that number by the amount they pay their employees per hour. Labor cost is included in your estimate.

To replace your flat roof, the old roof will have to be removed. That incurs a cost between $1,600 and $5,500. Once the underlayment, drip edge, and other materials are installed, the finish can be applied. There are four main finish options:

  • Bitumen
  • PVC
  • Thermoplastic olefin (TPO)
  • EDPM

Bitumen, the cheapest flat roof material, costs between $5 and $7 per square foot to install, while black EDPM, the most expensive material, runs between $6 and $14 per square foot. PVC and TPO are in the middle of this range. If you have a 2,000-square-foot roof, expect to pay between $10,000 and $28,000 on materials.

Frequently Asked Questions (FAQ)FAQ

What causes a flat roof to leak?

There are many reasons why a flat roof might leak, but some of the most common causes are improper installation, damage from weather or debris, and aging.

Can you reseal a flat roof?

Yes, a flat roof can be resealed. The process usually involves applying a new layer of sealant on top of the old sealant.

How do you maintain a flat roof?

Regular inspection is key to maintaining a flat roof. Look for any signs of wear or damage and repair them as soon as possible.


No one wants to spend money on a new roof. Repairing damage before it becomes serious is always cheaper than replacing an existing roof. Regularly check your for leaks, cracks and other signs of wear to avoid an expensive replacement job.

Having a durable, high-quality roof on your home not only protects you, your family, and your contents, but roofs also play an invaluable role in the structural stability of your home.