When a flat roof starts to show signs of wear and tear, it’s time to start thinking about a replacement. The average cost of a flat roof replacement is around $9,000 for 1,000 square feet, though typical prices can range from about $4,300 to $19,100. This price includes roofing materials and professional installation.
This price will vary depending on the size and type of flat roof, as well as your location. Keep in mind that this is just an average cost, and you may end up paying more or less depending on your specific circumstances.
Table of Contents:
- Average Costs
- Replacement Cost by Home Size
- Replacement Cost by Type
- Other Factors That Affect Cost
- Related Services
- Cost of Flat Roof Replacement by Location
- FAQ
Average Flat Roof Replacement Costs
| National Average Cost | $9,000 |
| Typical Price Range | $4,300 – $19,100 |
| Extreme Low End Cost | $2,500 |
| Extreme High End Cost | $42,000 |
Expect to spend somewhere in between $4,300 and $19,100 to replace a 1,000 square foot roof with flat roofing material. How can you tell if your project will be closer to the low or high end of that range? It mainly depends on the type of flat roof you want, the cost of labor in your area, and the structure of your roof.
If the area of roof you need replaced is smaller than 1,000 square feet, your cost might fall below this typical range, but don’t expect to spend less than $2,500. Larger projects (espeically for commercial properties) can cost as much as $42,000, or sometimes even more for extremely large buildings.
Flat Roof Replacement Cost by Home Size
The cost of replacing a flat roof depends on the size of the roof and the type of material used. A typical flat roof replacement costs between $4,300 and $19,100 per 1,000 square feet, including labor and materials.
If you’re not sure how large your roof is, here’s a rough-and-ready formula you can use to estimate its size based on the square footage of your home:
Home square footage x 1.5 = Approximate roof square footage
We calculated total project cost estimates for several home sizes in the table below, based on the average rate of $9,000 for 1,000 square feet.
| Home Size (sq ft) | Approximate Roof Size (sq ft) | Total Cost Estimate |
| 1,000 | 1,500 | $13,500 |
| 1,500 | 2,250 | $20,250 |
| 2,000 | 3,000 | $27,000 |
| 2,500 | 3,750 | $33,750 |
| 3,000 | 4,500 | $40,500 |
| 3,500 | 5,250 | $47,250 |
| 4,000 | 6,000 | $54,000 |
| 4,500 | 6,750 | $60,750 |
| 5,000 | 7,500 | $67,500 |
Flat Roof Replacement Costs by Type
There are several types of flat roofs, and the cost to replace them will vary depending on the type.
| Flat Roof Type | Price per Square Foot*labor and materials included |
| Built-Up Tar | $3 – $8 |
| Modified Bitumen | $3 – $6 |
| Polyurethane | $4 – $6 |
| Fiberglass | $4 – $7 |
| Rubber EPDM | $5 – $12 |
| Thermoplastic Polyolefin (TPO) | $4 – $11 |
| Flat Concrete | $4 – $8 |
Let’s take a look at the various types of flat roofs and their associated cost:
Built-Up Tar
Built-up tar roofs are moderately priced, with an average cost of $3 – $8 per square foot. They are made of multiple layers of tar paper and gravel, which are held together with asphalt or coal-tar pitch. Built-up tar roofs are durable and can last for 10 to 20 years, but they require regular maintenance.
Modified Bitumen
Modified bitumen is another option that has gained popularity in recent years, and it’s relatively affordable at $3 to $6 per square foot. This material is similar to asphalt, but it is reinforced with fiberglass or polyester matting. It is also heat-sealed, which makes it more resistant to leaks and damage from the sun.
Polyurethane
Polyurethane, also known as Spray Polyurethane Foam or SPF, is one of the most popular materials for flat roofs, and it’s not hard to see why. It’s durable, easy to install, and relatively inexpensive. But what exactly is the cost of replacing a flat roof with polyurethane? On average, you can expect to pay between $4 and $6 per square foot.
Fiberglass
Fiberglass roofs are typically less expensive to install than traditional asphalt roofs, but they may not last as long. The average cost to replace a fiberglass roof is between $4 and $7 per square foot.
Rubber
A rubber EPDM roof is durable and easy to install, making it a popular choice for both commercial and residential buildings. The average cost of an EPDM roof replacement is between $5 and $12 per square foot.
Thermoplastic Polyolefin (TPO)
TPO roofs are a recent innovation in flat roofing. These roofs are made from a thermoplastic material that is both waterproof and heat-resistant. The average cost to replace a TPO roof is around $4 to $11 per square foot.
TPO roofs are growing in popularity due to their energy efficiency and environmental friendliness. This type of flat roof comes from recycled materials that reflect sunlight to help keep your building cool in the summer.
Flat Concrete
Flat concrete roofing typically costs between $4 and $8 per square foot to replace. A flat concrete roof is a popular choice for many commercial and industrial buildings. Concrete is durable and can last for up to 40 years with proper maintenance.
Other Factors That Affect Cost
When considering the cost of flat roof replacement, several factors affect the average price in addition to the size and type of roof. These include homeowners insurance, roof drains and ventilation, surface coating, and permits and inspections.
Homeowners Insurance
Before you pay for a flat roof replacement, talk to your homeowners insurance (or business insurance) company. Roof replacements may be covered under your policy, especially if you’re getting your roof replaced because of damage caused by a natural disaster.
Every insurance policy is unique, so there’s no guarantee your roofing project will be covered. But if it is, insurance could take a huge chunk out of the price you pay out-of-pocket.
Roof Drains and Ventilation
Roof drains and ventilation prevent moisture build-up on your roof, which can lead to problems such as water damage and mold. Installing a single roof vent costs $300 to $600 on average.
Proper drainage and ventilation are especially important for flat roofs, which are prone to pooling water because they have no slope.
Surface Coating
Expect to pay $1 to $5 per square foot extra for a sealant layer on your flat roof, labor and materials included. Surface coatings can provide additional protection against weather and UV damage.
Surface coating is the process of applying a sealant material to the surface of a flat roof to protect it from the environment or enhance its appearance.
Permits
In most cases, you’ll need to get a permit to have any work done on your roof. Typical roofing permits cost between $200 and $500. Your roofing contractor will likely handle any necessary permits for you, then add the cost of the permit to your bill.
Related Services
A flat roof replacement is a major project that requires the expertise of a professional roofing contractor. While you already have a pro working on your flat roof, you might choose to add on some related services, such as:
Gutters Installation
If you’re planning on replacing your flat roof, you may also want to consider installing new gutters. The cost of gutter installation varies depending on the size and type of gutter you choose but typically ranges from about $4 to $12.66 per linear foot.
Gutters play an important role in protecting your home from water damage by channeling water away from your roof and foundation. And again, good drainage is essential for a flat roof. Professional installation is usually recommended for new gutters.
Roof Inspection
Roof inspections cost between $120 and $320 on average nationwide. A professional roof inspection can help determine if you need a roof replacement and if there are underlying issues with your roof’s structure.
Removal and Disposal of Old Roofing Materials
Removing and disposing of old roofing materials is an important part of the flat roof replacement process. The cost of removal and disposal will vary depending on the type and size of the roof, as well as the location of the property. Removal and disposal can cost between $1 – $4 per square foot.
Chimney Repair
Chimney repair costs $200 to $1,050 on average. The repairs may include replacing bricks or the mortar between the bricks, as well as repairing any damage to the flashing (the material that seals the space between your chimney and roof). The cost of repairs depends on the extent of the damage.
Skylight Installation
While you’re getting a new roof, it may be a good time to add that skylight you’ve been thinking about for years. Generally, skylight installation costs range from $1,060 to $2,930.
Skylights are a great way to let natural light into your home, and they can also help reduce energy costs.
Cost of Flat Roof Replacement by Location
The cost of flat roof replacement can vary a lot depending on where you live. In general, the cost will be higher in areas where labor and materials cost more.
For example, the cost of a flat roof replacement in an urban area like New York will likely be higher than the national averages discussed in this guide, while the cost in a rural area like Wyoming will probably be lower.
Climate Condition
Climate can also affect your costs. In general, roofing costs in colder climates will be higher than in warmer climates, due to the increased need for insulation and weatherproofing. On the other hand, hotter climates tend to cause more wear and tear on a flat roof, which means you might need a replacement sooner than you would in a milder climate.
If you live in an area prone to severe weather events (such as hurricanes or tornadoes), the cost of replacement will be higher because of the additional materials and labor required to ensure the new roof can withstand extreme conditions.
FAQ About Flat Roof Replacement
We strongly advise that you leave the replacement of a flat roof to the professionals only. Any work involving your roof requires specialist skills and knowledge. If you attempt to do it yourself, you could get hurt or cause serious damage to your home.
There are many benefits to installing a new roof, including:
● Increased energy efficiency: A new flat roof will be better insulated than an old one, leading to lower energy bills.
● Improved durability: A new flat roof will be more resistant to weather damage and wear and tear.
● Enhanced aesthetic appeal: A new flat roof can give your home or business a fresh, updated look.
● Greater peace of mind: Knowing that your roof has been replaced with a high-quality, durable product can provide peace of mind in the event of severe weather.
As a general rule of thumb, a flat roof should be replaced every 15 to 20 years. However, the life expectancy of your specific roof depends on many factors, such as the materials used and your local climate.
Leaks and pooling water are common in flat roofs.
The best way to determine if your flat roof needs replacement is to have it inspected by a certified roofing contractor.
The most common causes of flat roof leaks include:
● Improper installation (such as not installing a proper vapor barrier or not properly flashing around skylights or other openings)
● Clogged gutters
● Ponding water (which can deteriorate the roof membrane)
The best way to prevent flat roof leaks is to have the roof inspected and repaired by a professional. Inspection should be once a year.
When to Hire a Roofing Contractor
If your roof is showing signs of wear and tear, it may be time to replace it. The average national cost of a flat roof replacement is around $9,000 for 1,000 square feet, but typical prices can range from about $4,300 to $19,100. This price will vary depending on the size and type of roof, your location, and many other factors specific to your project.
When you’re ready for a new roof, RoofGnome connects you to the best roofing contractors near you.
Main Image Credit: U. J. Alexander / Canva Pro / License
