From £10,096
Need to find an Extension Builder near you for all your extension buildering work?
Pillar Contractors Ltd provides a local, trusted extensi...
From £10,472
We are a Design and Build Company, based in London.We focus on super prime and luxury residential renovations in and around London and internationa...
From £10,040
We Love Build - Three Arches is an established extension buildering business in W1K. We come highly recommended and provide competitive quotes for ...
From £10,024
Luxe Refurbs is an established extension buildering business in W1K. We come highly recommended and provide competitive quotes for your work.
From £10,088
Dominic Payte - Design & Build is an established extension buildering business in W1K. We come highly recommended and provide competitive quotes fo...
From £10,400
Starfish Properties is a trusted extension builder serving customers in W1K and the surrounding area. Contact us to today to get a competitive quot...
From £10,104
Trusted and professional extension builder in W1K. Experienced in all extension buildering work and keeping within budget and on quote. The Maybria...
From £10,352
Experienced extension builder ready to quote for your work. Mayfair Design is the best extension builder in W1K. No obligation free quotes and many...
From £10,080
Experienced extension builder ready to quote for your work. Azur London is the best extension builder in W1K. No obligation free quotes and many ha...
From £10,384
Experienced extension builder ready to quote for your work. Future Homes Design and Build is the best extension builder in W1K. No obligation free ...

Outbuilding costs in W1K range from the cheapest of £10,024 (Luxe Refurbs based in W1J) to the dearest of £10,472 (We Love Build based in W1J), but these are just estimates.
Comparing extension builders estimates for building an outbuilding gives you an idea of who will be better value, but the best way to compare costs is to get actual quotes.
Get rates and quotes to build an outbuilding in W1K by posting a job with HaMuch and we will send it to extension builders.
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 - £17,704

Two storey extension - £88,306

Build a timber frame extension - £26,204

Build a swimming pool - £81,204

Single storey extension - £59,080

Side return extension - £43,795

Install an RSJ - £2,404

Outbuilding - £10,204

Build a Mansard loft conversion - £52,204

Loft conversion - £35,663

Build a kitchen extension - £42,204

Hip to gable loft conversion - £42,204

Granny annexe - £87,204

Garden office - £10,204

Convert a Garage - £16,204

Garage - £18,704

Build a flat roof extension - £22,204

Build a dormer loft conversion - £42,204

Concrete foundations - £6,454

Convert a bungalow loft - £29,204

Convert a basement - £39,795