From £2,456
Relax... you have found a reliable extension builder in Muswell Hill. PLAN C - Design. Build. Create is a friendly and reliable company based in M...
From £2,512
We are builders with a difference.We are proud to be a family business. Brothers Pierre and Christian Carboni established PLAN C in 2011, having pr...
From £2,504
N10 Building Contractors Ltd are here to help customers who need an Extension Builder in Muswell Hill. We offer a competitive rate to complete all ...
From £2,224
Need an Extension Builder in Muswell Hill? Ally Electrical Services Ltd has been helping local clients (5 mile radius) with their extension builder...
From £2,568
Relax... you have found a reliable extension builder in Muswell Hill. CM Build is a friendly and reliable company based in Muswell Hill who conside...
From £2,224
Whether it's garden design, a garden studio or home renovations - we can do it. What you show me, what you imagine, we can build. Contact us now fo...
From £2,472
Galaia Limited are here to help customers who need an Extension Builder in Muswell Hill. We offer a competitive rate to complete all your extension...
From £2,280
Trusted and professional extension builder in Muswell Hill. Experienced in all extension buildering work and keeping within budget and on quote. Ar...
From £2,392
SJ Expert Building Services are here to help customers who need an Extension Builder in Muswell Hill. We offer a competitive rate to complete all y...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Muswell Hill it ranges from £2,224 (Ally Electrical Services Ltd based in N10) to £2,568 (CM Build based in N10).
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 Muswell Hill by posting a job with HaMuch and we will send it to extension builders in Muswell Hill.
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 - £17,713

Two storey extension - £88,319

Build a timber frame extension - £26,213

Build a swimming pool - £81,213

Single storey extension - £59,256

Side return extension - £43,894

Install an RSJ - £2,413

Outbuilding - £10,213

Build a Mansard loft conversion - £52,213

Loft conversion - £35,745

Build a kitchen extension - £42,213

Hip to gable loft conversion - £42,213

Granny annexe - £87,213

Garden office - £10,213

Convert a Garage - £16,213

Garage - £18,713

Build a flat roof extension - £22,213

Build a dormer loft conversion - £42,213

Concrete foundations - £6,463

Convert a bungalow loft - £29,213

Convert a basement - £39,894