From £22,048
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in W7. No obligation free quotes a...
From £22,280
Member since August 2026
Relax... you have found a reliable extension builder in W7. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in W7 who consid...
From £22,312
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £22,200
Relax... you have found a reliable extension builder in W7. Derryard Construction Ltd is a friendly and reliable company based in W7 who consider n...
From £21,968
B J CULLEN BUILDERS are here to help customers who need an Extension Builder in W7. We offer a competitive rate to complete all your extension buil...
From £22,032
Relax... you have found a reliable extension builder in W7. Major Building Contractors Ltd is a friendly and reliable company based in W7 who consi...
From £22,184
Need to find an Extension Builder near you for all your extension buildering work?
Sz Builders provides a local, trusted extension builderi...
From £22,712
Experienced extension builder ready to quote for your work. Render is the best extension builder in W7. No obligation free quotes and many happy cu...
From £21,896
Experienced extension builder ready to quote for your work. Jhon is the best extension builder in W7. No obligation free quotes and many happy cust...
From £21,880
Member since August 2025
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

A flat roof extension ranges from the cheapest of £21,880 (Can design and Construction based in Ig11) to the dearest of £22,712 (Render based in IG1), but these are just estimates. While they give you an idea of who will be better value, the best way to compare costs is to get real quotes.
Find out how much your flat roof extension will cost in W7 by posting a job with HaMuch. We'll send it to extension builders in W7.
Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Underpin a building - £17,651

Two storey extension - £88,227

Build a timber frame extension - £26,151

Build a swimming pool - £81,151

Single storey extension - £58,024

Side return extension - £43,201

Install an RSJ - £2,351

Outbuilding - £10,151

Build a Mansard loft conversion - £52,151

Loft conversion - £35,168

Build a kitchen extension - £42,151

Hip to gable loft conversion - £42,151

Granny annexe - £87,151

Garden office - £10,151

Convert a Garage - £16,151

Garage - £18,651

Build a flat roof extension - £22,151

Build a dormer loft conversion - £42,151

Concrete foundations - £6,401

Convert a bungalow loft - £29,151

Convert a basement - £39,201