From £2,304
Greater London, N16
Experienced extension builder ready to quote for your work. Barnaby Reynolds Design. is the best extension builder in N16. No obligation free quote...
From £2,392
Trusted and professional extension builder in N16. Experienced in all extension buildering work and keeping within budget and on quote. Amastic Roo...
From £2,240
Greater London, N16
Maddison & sons pride ourselves on attention to detail at the highest level.With an extensive background As Mains Contractors in construction fabri...
From £2,568
ACAR BROTHERS is an established and experienced local extension builder in N16. Please contact us for a free, no obligation quote and competitive r...
From £2,600
Stamford Hill, N16
Experienced extension builder ready to quote for your work. Five Star Builder is the best extension builder in N16. No obligation free quotes and m...
From £2,568
D Keighley Project Management Ltd are here to help customers who need an Extension Builder in N16. We offer a competitive rate to complete all your...
From £2,648
Greater London, N16
Celebrating over 13yrs in business and WE DO MORE THAN IT SAYS ON THE TIN! The company is owned and managed by me, I am a Building Surveyor...
From £2,184
Free Quotes WE OFFER GUARANTEES ON ALL WORK COMPLETED AND HOLD £2M INSURANCE FOR YOUR PEACE OF MIND Parkway Maintenance and Const...
From £2,344
Stamford Hill, N16
FISKA DESIGN & BUILD are here to help customers who need an Extension Builder in N16. We offer a competitive rate to complete all your extension bu...
From £2,392
Relax... you have found a reliable extension builder in N16. London Trowel Co. is a friendly and reliable company based in N16 who consider no job ...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in N16 it ranges from £2,184 (Parkway Maintenance & Construction based in N16) to £2,648 (My Plumbing & Heating Ltd based in N16).
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 N16 by posting a job with HaMuch and we will send it to extension builders in N16.
"RSJ re-installation" - N16, job posted 04/10/25
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 - £17,724

Two storey extension - £88,336

Build a timber frame extension - £26,224

Build a swimming pool - £81,224

Single storey extension - £59,480

Side return extension - £44,020

Install an RSJ - £2,424

Outbuilding - £10,224

Build a Mansard loft conversion - £52,224

Loft conversion - £35,850

Build a kitchen extension - £42,224

Hip to gable loft conversion - £42,224

Granny annexe - £87,224

Garden office - £10,224

Convert a Garage - £16,224

Garage - £18,724

Build a flat roof extension - £22,224

Build a dormer loft conversion - £42,224

Concrete foundations - £6,474

Convert a bungalow loft - £29,224

Convert a basement - £40,020