How Much Does Flat Roof Repair Cost?

Flat roofs may look simple, but when they start leaking or cracking, small issues can quickly turn into costly problems. How much does flat roof repair cost? This is a common question for homeowners, and knowing the answer early can help prevent expensive damage. Water damage often hides beneath the surface, and the longer you wait, the worse it gets. A small repair today might cost just a few hundred pounds, but ignoring it could result in thousands in costs for a full replacement. Let’s break it down so you know what to expect and how to avoid costly surprises.

Average Cost of Replacing a Flat Roof

The cost of replacing a flat roof depends on the roof’s size and the materials you choose. Here’s a realistic breakdown:

• Small flat roof repairs (sealing cracks or patching leaks): £200–£500. 
• Garage roof replacement: £1,200–£1,800
• Extension roof replacement: £3,000–£5,000+

On average, expect to pay £80–£120 per square metre for a full replacement of a flat roof. This helps calculate the repairing flat roofs or full replacement costs of flat roofs.

Flat Roof Material Costs & Lifespan

Choosing the right material affects both your upfront cost and your long-term flat roof repair cost:

1. Felt: £40–£60 per m²

Felt is the most budget-friendly option and quick to install. It works well for smaller projects, such as sheds, garages, and modest extensions. However, its durability is limited, usually lasting only 10 to 15 years. In regions with heavy rain or strong sun, it may wear faster. Regular checks and patching are essential to avoid leaks and damage.

2. EPDM rubber: £70–£90 per m²

EPDM is a highly reliable flat roofing material. Its flexibility and resistance to UV rays make it ideal for changing weather conditions. With minimal maintenance, EPDM can last 20 to 30 years. Homeowners appreciate that it can often be repaired without replacing the whole roof, reducing long-term costs and preventing leaks before they become serious.

3. GRP fibreglass: £90–£120 per m²

GRP offers a premium, seamless, and hard-wearing surface. It’s resistant to fire, water, and impact, which makes it one of the most durable options. Installed correctly, it can last over 30 years with minimal upkeep. Its smooth surface is easy to walk on, ideal for flat roofs that double as terraces or garden spaces.

For a deeper comparison of which option might best suit your home, check out our guide on flat roof materials.

What Affects the Cost of Flat Roof Repair

Several key factors shape the final flat roof repair cost or the price of a full replacement:

1. Roof type: 

Felt is the most budget-friendly, while fibreglass (GRP) and rubber (EPDM) sit at the higher end. The type you choose impacts both the upfront cost and the frequency of future repairs. Higher-quality materials cost more initially, but they reduce long-term maintenance expenses.

2. Roof size: 

Larger roofs require more materials and longer labour hours, often necessitating the use of scaffolding. Even a small increase in roof size can noticeably raise costs when calculated per square metre.

3. Roofing materials: 

The durability of materials affects both initial investment and long-term repair costs. EPDM rubber can last decades with minimal upkeep, whereas felt may need replacement sooner. Investing in higher-quality materials can save money over time.

4. Roof condition & complexity: 

Roofs with poor access, multiple joins, chimneys, or hidden water damage require more work. Complex designs increase labour costs because roofers need extra time and skill to complete the repairs correctly.

5. Insulation upgrades: 

Adding or improving insulation increases upfront costs but can lead to improved energy efficiency, lower heating bills, and reduced condensation problems, ultimately making it a long-term benefit.

6. Extra features: 

Skylights, roof vents, and specialist drainage systems improve comfort and performance but also add to the overall cost. Each feature requires additional materials and skilled installation. Extra features, such as skylights or specialised drainage systems, increase the repair cost of a flat roof.

Knowing these cost factors helps homeowners plan their budget properly and avoid surprises when fixing a flat roof.

Flat Roof Cost Breakdown

Here’s where your money typically goes during a flat roof repair or replacement:

1. Roofing materials: 

£40–£120 per m², depending on type (Felt, EPDM, GRP). Felt is cheaper but needs replacement sooner, while EPDM and GRP cost more but last longer. The materials chosen directly influence both cost and durability.

2. Scaffolding hire: 

£300–£800, depending on roof height and accessibility. Scaffolding makes sure the safety for workers and provides stable access to all areas of the roof. Hard-to-reach locations or taller buildings typically result in higher costs.

3. Removing the old roof: 

£30–£50 per m² covers labour for stripping old materials and preparing the base. Proper removal makes certain the new roof adheres well and lasts longer. Multiple layers or heavy roofing materials can increase time and cost.

4. Labour for installing the new roof: 

£200–£300 per day for skilled roofers. The price varies depending on experience, roof complexity, and additional features such as skylights or vents. Experienced professionals ensure the roof is installed correctly and lasts longer. Learn more about our roof repair services for expert help.

5. Waste disposal / skip hire: 

£150–£250 to remove old roofing debris. Large volumes or special disposal requirements can increase this cost. Proper disposal keeps your property clean and complies with safety standards.

Considering material, labour, and additional costs provides a clearer picture of the total roof repair costs. This helps compare quotes fairly and avoid hidden fees.

Extra Costs for Flat Roof Repairs

Not all expenses appear in the initial quote. Some hidden costs to watch for include:

• Emergency call-outs: £100–£200 for urgent jobs, especially during storms or heavy rain.
• Building regulations: If you are replacing more than 25% of your roof or adding insulation, inspections or additional paperwork may be required.
• Hidden damage: Rotten timber, damp insulation, or damaged joists can add £300–£1,000 to your final repair cost.
• Asbestos removal: Older garages may contain asbestos sheets that require specialist handling, which can increase disposal fees.
• Extended hire: Bad weather delays may add extra days of scaffolding or skip hire, costing £100+ per day.
• Planning permission: Usually not required unless the roof shape, height, or drainage is changed. Listed or conservation properties may need council approval.

Always request a full cost breakdown before work begins to avoid surprise charges.

Conclusion:

If your roof can’t be patched, understanding the cost of flat roof replacement helps you plan effectively. Small repairs might cost a few hundred pounds, but full replacements can run into thousands. Waiting too long only worsens the problem. Knowing the flat roof repair cost allows you to budget wisely and protect your home from bigger issues. Acting early could save thousands and preserve your property’s value and safety. For reliable flat roof work, consider hiring experienced roofers in Lewisham who can provide accurate assessments and quality repairs.

FAQs