New roof (new build / extension) in the UK
New roof construction on an extension or new build — full covering, underlayment, structure coordination.
Typical UK cost range
£90–£220/m²
National baseline. City-specific ranges are adjusted for local labour and access costs on the city pages below. See the full UK cost guide for the methodology and the factors that move a quote.
What the job involves
A new roof on an extension or new build is specified as part of the overall project. The roofer’s scope usually starts once the rafters and boarding are in place: laying the underlayment, fitting battens, and installing the chosen covering.
Building Regulations Part L and Part C apply to all new construction. The covering has to hit specific U-values, the underlayment has to resist the passage of moisture, and the detailing at abutments and eaves has to handle wind uplift — all covered in BS 5534.
What changes the price
- Covering material and underlayment specification.
- Coordination with the main contractor and other trades.
- Complexity — dormers, rooflights, solar provision.
- Height, pitch, and scaffolding plan.
Timeline: Roofer’s portion of a new-build extension is usually 3–8 days depending on complexity.
Pick a city for local pricing
Each city page has adjusted cost ranges, local context, and the roofers in our directory that cover it.
Major English cities
Other English cities
Northern Ireland
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Start my quote requestCommon questions
Who is responsible for Part L compliance — me or the roofer?
For a new build or extension, the person commissioning the work is the “relevant person” under Building Regulations. In practice the main contractor (or for a roof-only job, the roofer) takes responsibility for issuing the compliance certificate, often via CompetentRoofer self-certification.
Can I use a different covering from the rest of the house?
In most situations yes, but in conservation areas and on listed buildings the planning authority may require the extension roof to match the main house.
Related guides
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