The cost of a new flat roof is generally in the region of £1,000 – 4,000 in the UK depending on the scale and complexity of the flat roof.
There are several factors to consider when working out a flat roof replacement cost, including the type of material you’re going to use, the drainage system, the size of the roof and ease of access.
GRP roofing costs the most generally at £90 per square metre (m²), although other materials can be more cost-effective. However, it also has the most benefits and lasts the longest. This is a major consideration when working out the cost of a new flat roof.
Other materials such as EPDM rubber and roofing felt are more affordable but come with an array of pros and cons, all of which have an impact on your flat roof cost.
In this guide, we cover:
How much does it cost to replace a flat roof?
Most flat roof replacement costs will total in the region of £1,000 – 4,000, depending on the size of your roof. The main three factors a roofer will use to work out your flat roof cost are; the type of the material, the amount of material and the labour involved.
Flat roofs are normally more affordable than pitched roofs to replace. This is because a flat roof requires less material and labour to complete. They also tend to be cheaper overall because homeowners typically use flat roofs for comparatively small surface areas such as garages, extensions, and outhouses.
Below is a table of the most popular flat roof materials and their cost. You can use this to work out the approximate cost of a new flat roof.
Cost of flat roof materials per m²
Type of roofing | Cost per m² | Cost per 20m² |
Felt | £40 | £800 |
EPDM rubber | £45 | £900 |
Tiles | £50 | £1000 |
Slate | £60 | £1,200 |
Lead | £80 | £1,600 |
GRP fibreglass | £90 | £1,800 |
Typically, a roofer will charge around £200 per day with the average roof installation taking three days. This will be added to the cost of the materials in your final flat roof replacement cost. If you shop around, you may be able to get a better deal.
Also, there are some other considerations to take into account when researching the cost of a new flat roof, such as:
- Any repairs to the pre-existing structure
- Waste removal of the old roofing materials
- The location of your home
- The state of the drainage system
- How easy your roof is to access
All the factors above will ultimately determine your flat roof cost.
How much does a fibreglass roof cost?
The cost of a fibreglass roof is around £90m², or around £6,750 for a complete roof replacement.
Although the GRP roofing cost is one of the most expensive of all roofing materials, there are several benefits that it brings to the table.
My Local Toolbox recommends asking a local professional roofer to give you an estimate for the cost of a fibreglass roof. It’s not recommended that you attempt to take on the project yourself.
How long does a fibreglass roof last?
The cost of a fibreglass roof can be counterbalanced by the fact that it normally lasts over 25 years without needing to be replaced. This is because GRP fibreglass greatly reduces the pressure points of the roof’s surface where issues can arise.
For example, with other materials such as felt, water ingress can occur where two different parts of the material meet.
With fibreglass, there are no seams, meaning that water finds it extremely difficult to penetrate and cause a leak. This is an extremely important factor, so consider the pros and cons that contribute to a flat roof replacement cost.