Flat Roof Replacement Cost

How Much Does a New Flat Roof Cost?

In 2026, the average flat roof replacement costs between £1,500 and £6,000.

Prices depend on the size of the roof, the material you want to use, and how easy the roof is to access.

To break that down: materials account for around 60% to 70% of the total cost of a flat roof replacement, with the rest covering roofing labour rates.

They're often chosen for smaller areas like extensions, garages, and porches. This is because they're more affordable than the cost of a new roof with a pitched roof.

Flat roof replacement costs for a single garage are between £1,200 to £2,700 in the UK. This is based on a typical single garage roof area of about ~15m².

For easy comparison:

• Felt garage flat roof cost — £1,200 to £1,800
• Rubber garage flat roof cost — £1,650 to £2,400
• Fibreglass garage flat roof cost — £1,800 to £2,700

Let's move on and take a look at a few more examples, as well as more details on what drives the cost of a flat roof replacement.

Replacement Flat Roof Prices

To help you calculate how much a flat roof replacement costs in your case, here's a look at the cost of flat roofs per square metre (with materials and labour) for the 3 most popular flat roof materials:

• Felt flat roof cost — £80 to £120 per m²
• Rubber flat roof cost — £110 to £160 per m²
• Fibreglass flat roof cost — £120 to £180 per m²

Now, let's look at some quick cost illustrations for single and double garage flat roofs.

Single Garage Roof Costs

In the UK, the average size of a single garage is around ~15m². We've used this figure to calculate the following flat roof replacement costs:

Double Garage Roof Costs

Double garages in the UK range between 20m² and 25m²:

Other Flat Roof Replacement Costs

Flat roofs aren't just suitable for garages - they have a range of uses from cost-effective house extensions, dormers, porches, and shed roofs:

Key Things to Consider Before Replacing a Flat Roof

• What's the current condition of your roof's structure? If you have a damaged flat roof, the surface damage may have also impacted your roof's structure. This is especially common with water pooling which has led to sagging, rotten or weakened roof joists. In these cases, an entire roof rebuild is recommended, rather than replacing the flat roof membrane.
• Could your flat roof contain asbestos? If your structure was built pre 2000, you may have asbestos in the roofing material, most commonly found in cement. It's important you don't try to remove this yourself and only let a professional asbestos removal company take care of the substance for you.
• Does your flat roof already have a slight fall to allow for proper drainage? If you've been experiencing water pooling issues, it might be a sign that your flat roof is completely flat rather than having a slight fall which improves drainage. If it's not already present, get your drainage assessed when your flat roof material is being changed.
• Will there be any access issues? Where your flat roof is positioned can make a replacement very simple - or, it can become a lot more complex. Neighbours' boundaries, fences, and other structures can all play a part in making access tricky, so make sure you're upfront about any potential issues with your roofer from the start.

What's Included in a Flat Roof Quote?

Most flat roof quotes will include the following tasks:

• Existing flat roof removal
• Supply and installation of new roof covering, including basic trims/seals
• Labour costs

For balance, here's what's typically not included in a flat roof quote:

• Major structural repairs (e.g., rotten joists)
• Insulation upgrades
• Always clarify if: Scaffolding hire, waste removal, and VAT are included

How Much Does a Flat Roofer Cost?

When you're talking with roofers about flat roof costs, they'll often quote you a set price which includes labour and materials.

But, it's helpful to understand the labour component of the quotes you get:

• Labour typically accounts for around 30% to 40% of the total cost of a flat roof replacement.
• Flat roofer labour rates are usually around £250 to £350 per day, with rates towards the higher end in London and the South East.
• The labour cost of a flat roofer per hour is between £35 and £45. However, most roofers prefer to base their prices on day rates.
• Most roofers work as a team of 2, so daily labour costs for flat roof replacement will be around £500 to £700.

How Long Does a Flat Roof Replacement Take?

In typical cases, most UK homeowners should expect a flat roof replacement to take between 1 and 3 days.

How long installing a new roof takes will depend on the size of the roof, the material you want to use, and how accessible it is.

Felt and rubber flat roofs will typically take less time to install than a fibreglass or lead flat roof.

To put that into context, a small garage roof replacement might take around 1 day if felt is used, but the same roof could take around 3 days if you want to use fibreglass.

Flat Roof Repair Costs

While the cost of a flat roof replacement is more affordable than many homeowners expect, it's not always necessary. Sometimes you can extend the life of an existing flat roof with lower cost roof repairs, which can actually turn out more cost-effective than an unnecessary complete re-roof.

If you're unsure whether you need a full flat roof replacement, the best thing to do is get quotes from local roofers using MyJobQuote. You can then compare the advice you get and decide on the best path forward in your circumstances (quotes are free, with no obligation to go ahead).

When is Flat Roof Replacement Better?

Replacing a flat roof might be a better option if:

• The roof was installed more than 10 years ago.
• Minor problems across the surface, or there's a major issue.
• Problems are recurring, even after repairs by a roofer.

If there are recurring or extensive problems, then a complete flat roof replacement will likely be a more economical long-term option.

When is Flat Roof Repair Better?

Repairing a flat roof might be a better option if:

• The roof was installed in the last 10 years.
• The damage is quite minor (small leaks, one or two cracks, lifted edges).
• The underlying structural support is still in good condition.

The nature of the problem will impact the flat roof repair costs you're quoted. However, the table below shows what you should expect for common flat roof repair jobs.

Building Regulations & Planning Permission for Flat Roofs

Building Regulations

If you're completely replacing a flat roof, then building control approval will be required.

Only roofers that are members of the National Federation of Roofing Contractors (NFRC) Competent Person Scheme can self-certify that their work is compliant with UK Building Regulations.

After a scheme member has certified the work, they'll provide you with a Building Regulations Compliance Certificate. This confirms that the roof replacement meets all relevant UK Building Regulations.

Many scheme members will bundle self-certification and certificate issuance into the total cost you're quoted. But it's important to confirm this.

However: If the roofer you choose is not a scheme member, then they cannot self-certify the roof replacement work. In this case, you'll need to notify your local authority's building control department and pay an inspection fee.

Planning Permission

In most cases, replacing your flat roof on a like-for-like basis will be considered permitted development and won't require planning permission.

However: You may need planning permission in other cases.

If you're not sure, the best thing to do is to connect with a local roofer. They'll be able to advise you based on what you're looking to do.

What's Involved in Replacing a Flat Roof

Let's take a quick look at the process of replacing a flat roof when done by an experienced professional.

Before the Job Starts

• Initial Roof Inspection — The roofer should carry out a thorough inspection to find any hidden problems that impact the cost of the work. This will include getting onto the roof (if safe), walking around the outside of the building, and checking inside for signs of structural problems.
• Measuring the Area — The roofer will measure the roof and calculate how much material is needed and how long the job will take. This enables them to give you an accurate quote.

During the Job

• Removing the Old Roof — The existing roof covering will be stripped away and disposed of. In most cases, this will take around half a day.
• Installing the New Roof — Any structural problems are fixed and then the new flat roof is fitted. Felt and rubber roof replacements typically take 1 to 2 days, but installing a fibreglass or lead roof can take longer.

After the Job

• Final Checks — Once the new flat roof has been installed, the roofer will check over everything that has been done. This includes checking the seals and making sure that there aren't any leaks.
• Certification — If your roofer can self-certify their work, then they'll normally provide you with a Building Regulations Compliance Certificate within a few days. If they're not part of a Competent Person Scheme, you'll need to arrange an inspection with your local building authority.

Choosing a Flat Roof Material

Flat roofs are typically defined by the materials used. Your choice of material will have a significant impact on the durability, maintenance required, and overall cost.

Some of the best flat roof materials last longer and don't require as much maintenance, but there will be tradeoffs.

Let's take a look at the pros and cons of the most common choices in the UK.

Felt Flat Roof Cost

• Best for: Garages, sheds, small flat roofs
• Material cost: £50 to £80 per m²
• Average lifespan: 10 to 25 years

Felt remains one of the most common flat roof materials used by homeowners in the UK. A felt roof is an affordable option that's easy to install, but it's not as enduring as other flat roof materials.

Pros

• ✔ Affordable option
• ✔ Quick and easy to install
• ✔ Maintenance is simple

Cons

• ✖ Doesn't last as long as other materials, requiring frequent repairs
• ✖ More vulnerable to weather damage (i.e., storms)
• ✖ Not the most aesthetically pleasing option

Rubber (EPDM) Flat Roof Cost

• Best for: Home extensions, garages, high-end outbuildings
• Material cost: £80 to £120 per m²
• Average lifespan: 25 to 50 years

Rubber roofing is growing in popularity in the UK. It's more expensive than felt, but is a more durable option that doesn't need as much maintenance, offering a good balance between cost-effectiveness and functionality.

Pros

• ✔ Long-lasting and doesn't require much upkeep
• ✔ Quick and easy to install
• ✔ Eco-friendly material that can be recycled

Cons

• ✖ More expensive option than felt
• ✖ Colour fades over time
• ✖ Edges can lift or peel if incorrectly installed

Fibreglass (GRP) Flat Roof Cost

• Best for: Home extensions
• Material cost: £90 to £150 per m²
• Average lifespan: 20 to 30 years

Fibreglass roofing is a premium option that is more aesthetically pleasing than felt or rubber. As well as looking more modern, it's a longer-lasting option (20 to 30 years is realistic).

Pros

• ✔ Strong and durable flat roof material option
• ✔ Lightweight
• ✔ Clean and modern aesthetic

Cons

• ✖ Installation can take longer than other options
• ✖ Maintenance may be more difficult
• ✖ Heavy impacts can crack it

Lead Flat Roof Cost

• Best for: Older properties or high-end projects
• Material cost: £200+ per m²
• Average lifespan: 50 to 100 years

This is a premium, durable option that homeowners typically only pick if they're in an older property. They're water and corrosion-resistant, which can last longer than other material options if installed correctly.

This is quite a heavy flat roof material choice, so additional structural support may sometimes be advised by a roofing specialist to prevent sagging (this is especially relevant if the structure is older).

Pros

• ✔ Incredibly durable flat roof material option
• ✔ Malleable material that's convenient to work with
• ✔ Eco-friendly material that can be recycled

Cons

• ✖ Most expensive flat roof material option
• ✖ Limited availability in the UK
• ✖ Not all roofers will have experience working with this material

Asphalt & Roll-On Flat Roof Costs

• Best for: Sheds and outbuildings
• Material cost: £40 to £70 per m²
• Average lifespan: 20 to 30 years

Asphalt and roll-on flat roofs are typically only used to cover small outbuildings when you're trying to keep costs as low as possible. They're basic, budget options, but they'll usually need frequent maintenance.

Pros

• ✔ Cheapest flat roof material option
• ✔ DIY-friendly installation

Cons

• ✖ High maintainence requirements
• ✖ Only suitable for small structures

Do I Need to Replace My Flat Roof?

Flat roofs (that are correctly installed!) can last between 10 to 20 years. However, there are some clear signs that a flat roof replacement is required.

Here are 3 of the most common signs to look out for:

• Leaking — This is the most obvious sign that a repair or a replacement is needed. If water is getting inside, then there's a clear problem somewhere.
• Pooling Water or Sagging — Flat roofs are built with a slight slope to help water drain away. If the roof looks uneven or there's standing water, then it's a sign that the roof structure has weakened.
• Cracks, Blisters, or Tears — Damage to the surface of a flat roof (especially if it's felt or rubber) can let the water slowly seep in. This can be quite subtle, but it can lead to structural problems that are costly to fix.

Not sure what you need to do?

Use MyJobQuote to find a local roofer. They'll be able to assess whether you can get away with just doing some repairs or if it's time for a full flat roof replacement.

Ongoing Flat Roof Maintenance Costs

You'll want to keep on top of a few maintenance jobs to help your flat roof last as long as possible. Staying on top of small tasks (like clearing drains) can prevent serious problems from developing.

The table below lists the most common flat roof maintenance jobs, how often they should be done, and what typical maintenance costs to expect.

What Impacts Flat Roof Replacement Costs?

The cost of replacing a flat roof varies based on a few critical factors. The material you choose, the size of the roof, location, ease of access, and hidden problems all impact what to expect.

Flat Roof Material

The material you choose for a flat roof has a huge impact on the prices you're quoted. Felt, rubber, fibreglass, and lead are the four most commonly used flat roof materials.

The type of flat roof material you go with will also impact how long it takes roofers to install, as some are easier to work with than others.

Felt is the most affordable option and remains a popular choice among homeowners in the UK, but rubber is a good mid-range option that's growing in popularity.

Below, you'll find an image that shows how much a flat roof costs per m² (excluding labour):

Flat Roof Size

The size of the roof has a major impact on the overall cost of a flat roof replacement. Larger roofs require more materials and take longer to install, which drives up the total price.

Let's look at an example:

Typically, felt flat roofs cost between £50 to £80 per m² (supply only). This means that replacing the roof on a small porch is going to be much cheaper than replacing the flat roof on a single-storey extension.

However, a larger flat roof replacement will typically work out cheaper per square metre. This is because labour becomes more efficient on bigger jobs, which means that the flat roof cost per m² improves.

Labour Costs & Location

You should expect the labour cost to replace a roof to make up around 30% to 40% of the total price you're quoted.

Typically, a flat roofer costs around £250 to £350 per day. Expect the labour cost for a flat roofer to be at the higher end of this range in London and the South East.

Check out our local guides for more details on the cost of a flat roof replacement in your area:

• Flat Roof Replacement Costs in London
• Flat Roof Replacement Costs in Bristol
• Flat Roof Replacement Costs in Nottingham
• Flat Roof Replacement Costs in Birmingham
• Flat Roof Replacement Costs in Manchester
• Flat Roof Replacement Costs in Liverpool
• Flat Roof Replacement Costs in Leeds
• Flat Roof Replacement Costs in Edinburgh
• Flat Roof Replacement Costs in Glasgow

Keep in mind that many roofers work in small teams (2 to 3 people) so that the job is completed safely and efficiently.

Ease of Access & Scaffolding Hire

In the UK, it's the roofer's responsibility to comply with working at height regulations (Work at Height Regulations 2005).

If access isn't a problem and you're replacing a ground-floor flat roof, then they might advise that scaffolding isn't required. However, scaffolding will be necessary for flat roof installation that's above the ground floor.

If it's necessary, most roofers will include this in the total cost you're quoted. However, it's critical that you check this ahead of time to avoid unexpected additional costs.

If you have to arrange this yourself, the cost of hiring scaffolding will typically land between £800 and £1,200 for a flat roof replacement.

Waste Removal

There's a lot of waste that needs to be disposed of when replacing a flat roof, including the old roof materials and any structural parts that are being changed out.

Many roofers will include waste removal in the total cost you're quoted. However, this is another thing that's critical to confirm when getting prices from roofers.

If you have to arrange this yourself, the cost of hiring a skip is around £220.

Hidden Structural Problems

Even if a roofer performs a thorough inspection before giving you a quote, some structural problems might not be noticeable until after the old roof has been removed.

This can significantly impact the total cost of a flat roof replacement, so it's always wise to budget 10% to 15% extra in case something unexpected is discovered after work begins.

Checklist: Hiring a Roofer to Replace Your Flat Roof

Consider these key points before hiring a roofer for this job:

• Are they part of the (NFRC) Competent Person Scheme? Roofers who are part of this scheme can self-certify the work and provide you with a Building Regulations Compliance Certificate.
• Will they handle building control approval? If they cannot self-certify, ask if they'll coordinate with the local authority so you can get a Building Regulations Compliance Certificate.
• Is removal and waste disposal included? Most roofers include the removal of the old roof and waste disposal in their quotes, but make sure you confirm this if it isn't clearly stated.
• Are they insured? Even though it's not a legal requirement, tradespeople should have public liability insurance to protect you if something goes wrong.
• How much flat roof experience do they have? You're ideally looking for someone who has more than 2 years of experience working with flat roofs.
• Can they show examples of similar work? Take a look at any before-and-after photos on the roofer's MyJobQuote profile. This will give you an idea of what to expect from them.
• Do they have positive customer reviews? Other homeowners can rate and leave feedback on a roofer's MyJobQuote profile that they've hired. Check that other people are happy with their work.
• Is there a warranty or guarantee offered on the flat roof? Check with your roofing specialist to understand what is and isn't included before you agree to move forward with them.

FAQs