From £2,192
Relax... you have found a reliable extension builder in SW1A. London Projects Ltd is a friendly and reliable company based in SW1A who consider no ...
From £2,704
Welcome to Adamko Interiors Ltd. We specialize in customized interior design solutions, prioritizing customer satisfaction and creating safe, comfo...
From £408
Here at London Design and Build, our team of architects, interior designers, structural engineers and contractors, offer a bespoke, turn-key servic...
From £2,176
A to Z Builders Ltd are here to help customers who need an Extension Builder in SW1A. We offer a competitive rate to complete all your extension bu...
From £2,456
Originally established in 1996 ELV8 has set the highest standards within the building industry, achieving success by winning numerous gold awards f...
From £2,552
Experienced extension builder ready to quote for your work. Mayfair Design is the best extension builder in SW1A. No obligation free quotes and man...
From £2,224
Luxe Refurbs is an established extension buildering business in SW1A. We come highly recommended and provide competitive quotes for your work.
...From £2,456
F & F Building Services is an established extension buildering business in SW1A. We come highly recommended and provide competitive quotes for your...
From £2,240
We Love Build - Three Arches is an established extension buildering business in SW1A. We come highly recommended and provide competitive quotes for...
From £2,672
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...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in SW1A it ranges from £408 (London Design And Build based in SW1A) to £2,704 (Adamko Dry Lining London based in WC2N).
Comparing extension builders estimates for fitting an RSJ 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 install an RSJ in SW1A by posting a job with HaMuch and we will send it to extension builders in SW1A.
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 - £17,508

Two storey extension - £88,012

Build a timber frame extension - £26,008

Build a swimming pool - £81,008

Single storey extension - £55,160

Side return extension - £41,590

Install an RSJ - £2,208

Outbuilding - £10,008

Build a Mansard loft conversion - £52,008

Loft conversion - £33,825

Build a kitchen extension - £42,008

Hip to gable loft conversion - £42,008

Granny annexe - £87,008

Garden office - £10,008

Convert a Garage - £16,008

Garage - £18,508

Build a flat roof extension - £22,008

Build a dormer loft conversion - £42,008

Concrete foundations - £6,258

Convert a bungalow loft - £29,008

Convert a basement - £37,590