How much does flat roof repair cost in 2024?

Flat roofs are a popular solution for both business hubs and contemporary-style homes. They cost about 20% less than the sloping options, but they are more prone to drainage issues, which lead to ponding and leaks. Besides, the membrane covering a flat roof for waterproofing tends to be damaged with time, allowing water to seep under the underlayment and making the leakage problem more acute every year. That is why flat roofs' average service life is less than 25 years.

Nevertheless, you should not give up this space-enhancing solution. Instead, go for a quality flat roofing material and follow maintenance instructions to prolong its service life. Inspect your roof regularly and repair it as soon as the damage is revealed. Remember, there are no minor issues when it comes to the integrity of a flat roof.

The national average repair cost varies from $300 to $1.250 for a standard 1,500-square-foot roof, while the typical homeowner's bill is $750 for a standard flat roof leak repair. The minimum price can be as low as $50 while fixing major damage can require a $4.000 budget.

The average flat roof repair costs 

National average cost	$750
Low-end cost	$50
High-end cost	$4.000
Average price range	$300 - $1.250

The average cost of flat roof repair by roof size

The size of the roof is always taken into account in the final estimate. If only a small part of your roof needs renovation, it will cost less than if the entire roof needs to be repaired. When budgeting, you can target a flat roof repair cost per square foot that averages $3 - $15.

Size	Average repair cost
50 sq. ft.	$150 - $750
100 sq. ft.	$300 - $1.500
150 sq. ft.	$450 - $2.250
200 sq. ft.	$600 - $3.000
500 sq. ft.	$1.500 - $7.500
1000 sq. ft.	$3.000 - $15.000
1,500 sq. ft.	$4.500 - $22.500
2,000 sq. ft.	$6.000 - $30.000

Labor cost to repair a flat roof

Professional installation and repair are standard requirements of many flat roof manufacturers. If not followed, the warranty provided to you upon purchase may be void. That's why contractor rates are usually factored into the flat roof repair cost. 

Professional roofers charge $50 - $150 per hour. But note that you pay not only for the hours spent on the repair itself. Contractors also devote time to conducting a pre-repair inspection, diagnosing problems, assessing damage, and making post-repair verification. In addition, if they take a long time to get to your area, the price may increase. But with MyHomeQuote, you can easily find licensed contractors near you and not overpay for their travel time.

Flat roof repair costs by material

Flat roof materials themselves differ in price, affecting the cost of replacing them accordingly. Also, some materials require advanced skill and care from roofers to repair them. That is why you should always consider material type when budgeting for a renovation project.

Material type	Average cost per sq. ft.
EPDM	$6 - $18
Modified bitumen	$3 - $7
GRP	$3 - $6
Metal	$5 - $15
Concrete	$4 - $10

EPDM

Ethylene propylene diene terpolymer, or EPDM, is widely used in roofing projects due to its energy efficiency and high weather resistance. But EPDM roofs are most prone to shrinkage over time. Plus, they can be punctured by sharp objects in extreme weather or careless maintenance. Repairing a black EPDM roof costs $6 to $14, while a white EPDM option renovation costs $8 to $18 per square foot. The price difference is due to the better reflective properties and, as a result, the greater energy efficiency of white materials.

Modified bitumen

Homeowners value modified bitumen roofs for their resistance to UV radiation, heat, and cold. But at the same time, they are pretty fragile and, therefore, easily damaged by hail, falling branches, or foot traffic. Fixing identified issues can cost you $3 - $7 per square foot.

Glass-reinforced polyester (GRP)

A GRP or fiberglass flat roof can last for decades when properly installed. But you still need to invest in its repair. In particular, these roofs can split or crack over time. In this case, the flat roof repair cost per foot is $3 - $6. But if not repaired in time, these cracks can compromise the roof structure and its waterproofing layer.

Metal

Depending on the selected metal type, the service life of this roofing can reach 70 years, even without extra care. However, metal roofs can expand and contract under rapid temperature changes, resulting in leaks as well as damaged fasteners and seams. If this happens, you should be ready to react immediately. Metal flat roof repair cost per foot varies from $5 to $15.

Flat concrete

Although concrete is durable, it can still crack over time due to frequent freeze-thaw cycles or extreme temperatures. If these cracks are not repaired in time, water can freeze inside the gaps or seep into your home, damaging the roof and the interior. A concrete roof repair can cost about $4 - $10 per square foot.

Flat roof repair cost by damage type

While some damages require hours to repair, others take days, if not weeks, of painstaking work by a roofer. A minor problem you have identified may be just the tip of the iceberg that indicates more severe damage. Still, only a professional roofer can determine this for sure.

Damage type	Average repair cost
Sagging	$750 - $2.500
Leakage	$400 - $1.300
Ponding	$75 - $500
Shrinkage	$350 - $1.250
Cracking	$150 - $1.500
Hail damage	$750 - $4.000
Blistering	$250 - $1.000
Alligatoring	$350 - $1.000

Sagging

Sagging can result from structural issues, poor original construction or design, excessive loading from accumulated snow or water, or roof wear. Regardless of the cause, the problem should be fixed immediately. It could cost you $750 - $2.500, but delaying repairs can cause leaks, broken insulation and sealing, reduced home aesthetic value, and even property damage.

Leakage

Leaks can be your most significant pain point if you've chosen a flat roof for your project. First, they can occur for various reasons, including water build-up, an improperly installed or damaged membrane, and worn or corroded flashing. Second, it can be difficult for a roofer to find the source of a leak because water can overcome significant gaps under the membranes before dripping onto the floor. As a result, the identification of the cause and the search for the source increase the renovation price. But the average flat roof leak repair cost is $400 - $1.300.

Ponding

Flat roofs have a slight slope which prevents them from shedding water quickly. As it accumulates, ponding can form on the surface. Often fixing this problem requires cleaning or repairing the drainage system, which is not expensive. The average cost to repair flat roof ponding ranges from $75 and $500. But if the ponding has caused sagging, your renovation price may increase significantly.

Shrinkage

This problem is most familiar with modified bitumen or EPDM flat roofs. It results from improper fastening and/or sealing, poor ventilation, moisture accumulation, temperature fluctuations, and sunlight. Removing shrinkage can cost you $350 - $1.250.

Cracking

Cracks are a common issue with fiberglass, concrete, and other roofing materials. While the cracks are small, their repair does not require significant costs. But if not identified and eliminated promptly, the cracks become more profound, which increases your spending. Thus, flat roof repair costs between $150 and $1.500, depending on the crack size.

Hail damage

Нail can damage the membrane, causing leaks. But apart from that, you may also encounter rips, holes, tears, and dents. A roofer can often patch or fill in hail damage, but sometimes replacing large roof sections is unavoidable. That is why such repairs vary from $750 to $4.000.

Blistering

Blistering or bubbling is the appearance of bulges on the surface of your roof. It occurs when air or moisture enters the membrane layers due to poor ventilation, ultraviolet (UV) radiation, or poor installation of roofing materials. Its fix can cost you $250 - $1.000. But if repairs are delayed, blistering can damage the structure, reduce insulation properties, and shorten the roofing system lifespan.

Alligatoring

When roofing materials wear and crack, their appearance resembles alligator skin, which gives the name to this damage. First, it spoils the exterior of your home. But no less critical that alligatoring materials are more likely to leak and tear, which threatens your interior. Affected areas are usually sealed or patched, costing between $350 and $1.000.

The average cost of flat roof repair by project

Each problem can have different causes. For example, if you encounter a leak, a professional contractor will inspect your roof to determine which area has failed. The final quote will be based on the difficulty of repairing that area.

Project type	Average repair costs
Flashing repair	$200 - $750
Drain repair	$75 - $500
Drip edge repair	$150 - $400
Membrane repair	$300 - $1.750
Seams repair	$250 - $1.000

Flashing repair

Roof flashing is made from aluminum, copper, or steel to seal the edges. Although weather-resistant, strong winds can move or lift it, especially if not securely fastened. If you live in an area with an extreme climate, temperature fluctuations may cause the flashing to expand and contract, damaging the joints. In this case, residential or commercial flat roof repair costs $200 to $750. 

Drain repair

Due to their shallow slopes, flat roofs are less able to remove water. As a result, it accumulates and seeps into the roof system causing leaks. This type of roof requires special systems to help with water drainage. Over time, these systems can be damaged by extreme temperatures or storms as well as clogged by roof debris. This kind of flat roof repair costs around $75 - $500.

Drip edge repair

These L-shaped elements are positioned at the roof edges. They provide water drainage and prevent it from getting under the roofing materials. Since drip edges are made of metal, they are durable. Still, extreme weather or falling debris can damage or dent them, making it difficult to drain water accordingly. Their cleaning and patching costs range from $150 to $400.

Membrane repair

A rubber or modified bitumen membrane is designed to keep water out. Punctures in it are the most common causes of leaks. They can be due to weather conditions, poor installation, careless foot traffic, or simply wear and tear. The roofer seals the punctured areas with cement and lays roofing materials on top to hold the membrane in place. Depending on the damaged area size and the severity of the damage itself, this could cost you $300 - $1.750. 

Seams repair

Seams are the weakest point of your flat roof. Under the influence of weather conditions or due to age, they can diverge and let water through. Their repairs cost $250 - $1.000 and are done every 10 years on average. But if too many seams have come apart on your roof, the contractor may advise you on a replacement since the repair no longer makes sense.

The cost to repair a flat roof by approach

The repair method is chosen depending on the type of damage. Its cost mainly depends on the experience and skills required for its application. However, the severity of the damage and the scope of work also matter.

Repair approach	Average cost
Patching	$150 - $1.500
Resealing	$400 - $1.250
Resurfacing	$250 - $1.500

Patching

Contractors usually use this repair approach when dealing with cracks or holes in a flat roof. The price of patching starts at $150 and can go up to $1.500 depending on the roof's material and damage extent.

Resealing

As the name suggests, the resealing approach works when the current seals are worn or damaged, which can happen every 2-4 years. But if heavy snow and rain are common in your area, it is advisable to reseal your roof more frequently to minimize the risk of water infiltration. With this approach, flat roof repair costs between $400 and $1.250.

Resurfacing

Roofing issues like blistering and alligatoring are often fixed by resurfacing. The process involves restoring an existing roof's appearance to extend its service life and improve its performance without complete replacement. Depending on the amount of work, contractors can charge you from $250 to $1.500.

Flat roof improvement cost

The following services are optional additions to the main repair work. Although you may not need some of them, it is better to know their cost for more accurate budgeting.

Service type	Average price
Cleaning	$0.10 - $0.40 per sq. ft.
Painting	$500 - $1.500
Insulation	$1.000 - $2.000
Installing gutter guards	$1.200 - $2.000
Waterproofing	$150 - $1.000
Ventilation	$300 - $700
Torching down	$4.500 - $9.000

Cleaning

The drains can't handle the water outflow if they are clogged. So cleaning them out on time is a simple yet effective way to prevent water seepage and subsequent leaks. In addition, you will pay only $0.10 to $0.40 per square foot for this service, which is significantly lower than the leaking flat roof repair cost.

Painting

Aesthetics boost is just one of the roof painting benefits. UV-resistant coatings save your roof from the UV rays' harmful effects, while waterproof paints create an additional protective barrier against water seepage. This service can cost from $500 to $1.500.

Insulation

While you can spend $1.000 - $2.000 on roof insulation, it pays off in the long run. First, your energy bills go down as you no longer need to use your heater in the winter. Second, you are unlikely to encounter a mold issue as the insulation controls condensation and prevents moisture from building up.

Installing gutter guards

Leaves, twigs, and other debris often accumulate in gutters, making it difficult for water to drain off a flat roof. As a result, you end up with mold, leaks, and, in the worst-case scenario, damage to the roof's structure. All of this can be prevented by installing the gutter guard system for an average of $1200-$2000.

Waterproofing

If frequent snowfalls and rains are typical for your area, waterproofing can be an additional guarantee that water does not seep into your home. In addition, it retains heat, thereby increasing energy efficiency. These benefits justify waterproofing's cost of $150 - $1.000.

Ventilation

The most common consequences of poor ventilation are moisture build-up, leading to shrinkage, blistering, and mold growth. Fixing all these problems will be more expensive than installing new ventilation, which costs an average of $300 - $700.

Torching down

Also known as torch-applied roofing, this method is designed to create a strong seal. Thanks to it, the bitumen-based membrane securely bonds with the roof surface, forming a continuous, watertight layer. As a result, it ensures strong seam integrity and prevents leaks. Torching down can cost you $4.500 - $9.000, but waterproofing, durability, and energy efficiency are provided. 

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