How much does flat roof repair cost?
How much does flat roof repair cost?
$2.50 – $10.00 cost per square foot installed
$300 – $1,100 average cost to repair
Flat roof repair cost
Flat roof repair costs $2.50 to $10.00 per square foot or $300 to $1,100 on average, depending on the material and extent of damage. Flat roof leak repair costs $500 to $1,200 on average. Consider replacing flat roofs older than 10 years for $3 to $11 per square foot.
| National average cost | $900 |
| Minimum cost | $100 |
| Maximum cost | $5,000 |
| Average range | $300 to $1,100 |
Flat roof repair cost estimate by type
| Repair | Average cost |
|---|---|
| Leak repair | $500 – $1,200 |
| Coat / reseal / recover | $500 – $2,000 |
| Tear off and full replacement | $4,000 – $16,800 |
Flat roof leak repair cost
Flat roof leak repair costs $150 to $500 for minor sealing or $500 to $1,200 to replace and seal the roofing. Repairing extensive leaks and structural damage costs $1,200 to $3,000. Small roof leaks can eventually cause structural issues if left unresolved.
| Leak Size | Average cost | Repairs |
|---|---|---|
| Small | $150 – $500 |
|
| Average | $500 – $1,200 |
|
| Large | $1,200 – $3,000 |
|
Installing a leaf guard over gutters may help prevent pooling water and leaks.
Cost to coat or reseal a flat roof
Sealing or coating a flat roof costs $1 to $4 per square foot or $500 to $2,000 on average, depending on the roof material, sealant type, and job complexity. Resealing increases a roof’s lifespan.
| Roof size (square foot) | Average cost |
|---|---|
| 100 | $100 – $400 |
| 250 | $250 – $1,000 |
| 500 | $500 – $2,000 |
| 1,000 | $1,000 – $4,000 |
Not all sealant types have the same water resistance.
Use a silicone-based or acrylic-elastomeric coating for modified bitumen and EPDM roofs.
Recovering a flat roof with PVC, TPO, or EPDM membrane costs $4 to $10 per square foot, depending on the material. A partial or full recover is a good option for a roof with damage on its surface but not its insulation or decking.
Flat roof replacement cost
A flat roof costs $3 to $11 per square foot to replace on average. Consider replacing instead of repairing a flat roof that is 10 to 15 years old and needs extensive repairs.
| Roof size (square feet) | Average cost to replace |
|---|---|
| 800 | $2,400 – $8,800 |
| 1,000 | $3,000 – $11,000 |
| 1,500 | $4,500 – $16,500 |
| 2,000 | $6,000 – $22,000 |
| 2,500 | $7,500 – $27,500 |
| 3,000 | $9,000 – $33,000 |
| 3,500 | $10,500 – $38,500 |
Additional costs to repair a flat roof
The cost to repair a flat roof depends on the roof size, material, job complexity, and damage severity.
| Factor | Average cost |
|---|---|
| Blistering, cracking, alligatoring repair | $250 – $1,250 |
| Sagging / water pooling repair | $800 – $2,500 |
| Flashing repair | $200 – $500 |
| Rafter repair | $300 – $1,700+ |
| Roof decking repair | $200 – $2,500 |
| Water damage / structural repair | $500 – $3,000 |
| Cleaning | $250 – $600 |
| Insulation | $1,100 – $9,000 |
| Snow removal | $200 – $500 |
| Drip edge installation | $150 – $600 |
| Roof vents installation | $200 – $700 |
| Painting (metal) | $1,450 – $3,250 |
| New gutters | $600 to $1,600 |
| Roof inspection | $100 – $400 |
| New drain | $70 – $340 |
Blistering / cracking – Repairing a blistering, cracking, or alligatoring roofing membrane costs $250 to $1,250 on average. These issues are typically caused by sun exposure, severe weather, and age.
Sagging / pooling – Sagging roof repair costs $800 to $2,500 for sections up to 100 square feet. Fixing minor sagging may only require basic rafter ties. Severe cases may require replacing rotted rafters or a full roof replacement.
Flashing – Roof flashing repair costs $200 to $500 on average for skylights, chimneys, and vents. Completely replacing and resealing all flashing costs $400 to $1,000. Flashing is typically metal and prevents leaks around fixtures.
Rafter – Rafter repair costs $300 to $1,700+. Rafters should be repaired or replaced if there is water damage or wood rot.
Roof decking – Roof decking replacement costs $2 to $5 per square foot. Decking, or sheathing, is the plywood layer between trusses and roofing material.
Water damage – Roof structure repair costs $500 to $3,000, depending on the severity. Roof structure and water damage may require replacing decking, underlayment, and roof material.
Cleaning – Roof cleaning costs $250 to $600 or $0.15 to $0.70 per square foot on average, depending on the cleaning method.
Insulation – Replacing roof underlayment costs $1,100 to $9,000 or $0.75 to $4.00 per square foot. Polyiso insulation is used instead of underlayment on rubber roofs and costs $0.50 to $3.00 per square foot with installation.
Snow removal – Roof snow removal costs $200 to $500 and is recommended after heavy snowfall of 6 inches or more.
Drip edge – Drip edge installation costs $150 to $600 or $1.50 to $3.00 per linear foot when reroofing a house. Installing drip edges on an existing roof costs $5 to $9 per linear foot.
Vent – Roof vent installation costs $200 to $700.
Painting – Metal roof painting costs $1,440 to $3,264 or $1.20 to $2.72 per square foot.
Gutters – Installing gutters costs $600 to $1,600 or $4 to $8 per linear foot on average.
Drain – Repairing or adding a roof drain costs $70 to $340 on average. Proper drainage prevents pooling water and expensive repairs.
Cost to repair a flat roof by material
| Material | Repair cost per square foot |
|---|---|
| Built-up roof cost | $2 – $7 |
| EPDM rubber membrane roof cost | $2 – $10 |
| TPO membrane roof cost | $2 – $9 |
| PVC membrane roof cost | $3 – $12 |
| Fiberglass (GRP) roof cost | $3 – $8 |
| Modified bitumen roof cost | $3 – $8 |
| Rolled asphalt roof cost | $1 – $6 |
| Spray foam roof cost | $2 – $3 |
| Metal roof cost | $5 – $10 |
| Concrete roof cost | $4 – $15 |
Labor cost to repair a flat roof
Roofing professionals charge $45 to $75 per hour for labor on average, depending on the scope and type of damage. The following factors affect the cost to repair a flat roof:
Roof type – Some flat roof materials, such as metal or concrete, cost more to repair.
Roof size, pitch, and slope – Labor prices are higher for large roofs and pitches higher than 4:12.
Size and type of damage – Some repairs take longer to complete, increasing costs.
Permits – Roof repair permits cost $75 to $250, depending on the size and location. Contractors typically include permit fees in the estimate.
Emergency fees – Many contractors charge $200 to $300 for 24/7 emergency repairs.
Frequently asked questions
How often should a flat roof be replaced?
A flat roof should be replaced after 15 to 25 years. Regular inspections may catch damage before it becomes too expensive. Consider replacing instead of repairing a flat roof that is 10 to 15 years old and needs repairs.
How often should a flat roof be inspected?
A roof inspection costs $100 to $400 on average, depending on the roof size, complexity, and inspection method. Professional inspections are recommended every 3 to 5 years, but you should self-check at least once per year to look for damage.
Why do flat roofs leak?
Flat roofs leak because of cracks or punctures in the membrane, worn flashing or seams, or clogged drains. Drainage problems and small leaks are simple to fix but may cause expensive repairs if ignored.
Are flat roof repairs covered by insurance?
Homeowners insurance may cover flat roof repairs for damage caused by an accident or severe weather but not for normal wear and tear. Check your insurance for coverage details.
Getting estimates from roof repair contractors
Before hiring a roof repair contractor near you, be sure to:
Get three or more quotes to compare.
Read their reviews on HomeGuide and Google.
Look for companies with these qualifications:
State contractor license
National Roofing Contractors Association (NRCA) certification
International Association of Certified Home Inspectors (InterNACHI) certification
Select a certified, insured, bonded company with five or more years’ experience.
Be careful with extremely low or high price quotes.
Beware of companies who recommend a full roof replacement if only repairs are needed.
Verify that the roofing contractor has experience with your roof type.
Ask for a clear written estimate and warranty before work begins.
Avoid large upfront payments. Instead, negotiate a payment schedule and save receipts.
Questions to ask
How long have you been repairing flat roofs?
Are you licensed, insured, and bonded?
Can you provide references for past work?
Are you a member of the NRCA or InterNACHI? What certifications do you have?
Do you offer any specials or discounts for storm damage?
Can you provide a detailed quote?
Does your quote include waste disposal or taxes?
What extra costs should I expect?
How long will the project take?
What will you do in the event of unexpected bad weather?
How will you access my roof?
Will the repairs require a permit, and if so, will you obtain one?
What does your warranty include?
Do you offer financing?