How Much Should You Pay For a New Flat Roof?

Update; this page hasn’t been updated for a few years, you can see an up to date price for flat roofs here.

Thanks for visiting my web site here at Daniel’s Roof.

I have over 17 years experience in the roofing industry, from tiling and cement work to Upvc roofline fascias and guttering. I have worked on hundreds of houses in the United Kingdom and have plenty of experience and knowledge that I wish to share.

What are the average flat roof costs? By that I mean; how much does it (or should it) cost to replace a typical felted flat roof?

Below is a price guide based on my experience and that of several flat roof specialists I have had the pleasure to work with over the last few years.

Single Garage Flat Roof

All quotes are not equal so the flat roof price guide on this page is for a single garage roof that also needs new timber decking.

Do bear in mind that I live in Camberley, Surrey so if you live in central London then you may pay more, if you live up north then expect to pay less.

Works Schedule:

  • Sweep off existing stones to flat roof.
  • Rip up existing felt.
  • Remove existing decking boards (rotten).
  • Secure new 18mm marine grade OSB ply boards to roof.
  • Tack underlay to decking boards.
  • Secure a mineral finish cap layer by way of gas torching.
  • All waste material to be removed and disposed of.

Total Flat Roof Cost: £850.00 (ex VAT)

On many flat roofs the existing decking boards can be left in place and there is no need to replace them. This depends on the condition of the boards, their age and what they are made from. Chip board tends to sag or disintegrate when wet, so if your flat roof has been leaking for a while then they will probably need replacing.

There are between five and six decking boards on a single garage roof.

The cost of a new flat roof felt covering excluding the decking is around £550.00 (ex VAT) for a single garage roof.

The prices quoted above are what you can expect to pay of you choose a medium sized company with several employees. If you instruct a “one man” type roofing contractor who has less overheads then expect to pay less.

Material and Labour Cost

There are always variations in cost, some materials are cheaper than others and labour costs can vary.

Here is a breakdown of the materials and labour cost for a “torch on” bitumen felted flat roof:

Decking Boards – £40.00 each

Felt: £150.00

Waste Disposal: £80.00

Labour: (2 employees) £250.00

Profits margins to be added as well as VAT

Two or Three Felt System?

The two layer system is most commonly seen on garage and shed roofs while a three layer system is used on dormers or any other roof where there is a habitable area underneath.

How Long Will the Work Take?

The work will take one day to complete, if the boards don’t need replacing then it will take just under one day. The weather will need to be dry or the garage roof will need to be sheeted halfway through the job and this add time to the project.



What About Other Types of Flat Roof Materials?

Bitumen based felts are by far the most popular materials, they are also one of the cheapest as there are so many manufacturers. Rubber materials (called EPDM) or fibreglass are also available. EPDM and fibreglass systems are known to last longer, but are more expensive so only consider them if you intend to stay in the property for 15+ years.

Rubber Flat Roof Costs

Expect to pay around £1400-£1500 for EPDM flat roof covering, including new boards for a single garage flat roof.


GRP or fibreglass must be laid onto boards that are new or in excellent condition. So if your single garage roof is more than a few years old expect to pay around £1800, that price includes new boarding.

Get a Quote

Whether you live in London, Glasgow, Swansea or anywhere in between you can read reviews of local roofers and get a quote for your flat roof project:

Read Reviews and Get a Quote Here