From £1,872
Custom Build Construction are here to help customers who need an Extension Builder in SA4. We offer a competitive rate to complete all your extensi...
From £1,944
L2 Construction Limited is an established and experienced local extension builder in SA4. Please contact us for a free, no obligation quote and com...
From £2,280
Worked in building all my working life.
Worked as a builder 30 plus year's.
Am a hands on builder. Have built hou...
From £1,832
Building Service Controls Ltd is an established and experienced local extension builder in SA4. Please contact us for a free, no obligation quote a...
From £2,048
Rowan Evans Building Contractors is an established extension buildering business in SA4. We come highly recommended and provide competitive quotes ...
From £2,216
Relax... you have found a reliable extension builder in SA4. Signature Project Solutions Ltd is a friendly and reliable company based in SA4 who co...
From £2,200
Experienced extension builder ready to quote for your work. Improve Not Move is the best extension builder in SA4. No obligation free quotes and ma...
From £1,936
The Rod Squad is a trusted extension builder serving customers in SA4 and the surrounding area. Contact us to today to get a competitive quote for ...
From £2,168
Relax... you have found a reliable extension builder in SA4. Home Maintenance & Improvement is a friendly and reliable company based in SA4 who con...
From £1,848
Relax... you have found a reliable extension builder in SA4. R M R BUILDING CONTRACTORS is a friendly and reliable company based in SA4 who conside...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in SA4 it ranges from £1,832 (Building Service Controls Ltd based in SA5) to £2,280 (Apex Building Services based in SA4).
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 SA4 by posting a job with HaMuch and we will send it to extension builders in SA4.
"Install an RSJ" - SA5, job posted 09/11/26
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Gorseinon | £29 | £228 |
| Install An RSJ near Llanelli | £29 | £231 |
| Install An RSJ near Swansea | £29 | £229 |
| Install An RSJ near Neath | £30 | £225 |
| Install An RSJ near Port Talbot | £31 | £227 |
| Install An RSJ near Neath Port Talbot | £31 | £224 |
| Install An RSJ near Carmarthen | £26 | £205 |
| Install An RSJ near Carmarthenshire | £26 | £205 |
| Install An RSJ near Maesteg | £38 | £283 |
| Install An RSJ near Pyle | £34 | £262 |
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 - £17,334

Two storey extension - £87,752

Build a timber frame extension - £25,834

Build a swimming pool - £80,834

Single storey extension - £51,688

Side return extension - £39,637

Install an RSJ - £2,034

Outbuilding - £9,834

Build a Mansard loft conversion - £51,834

Loft conversion - £32,198

Build a kitchen extension - £41,834

Hip to gable loft conversion - £41,834

Granny annexe - £86,834

Garden office - £9,834

Convert a Garage - £15,834

Garage - £18,334

Build a flat roof extension - £21,834

Build a dormer loft conversion - £41,834

Concrete foundations - £6,084

Convert a bungalow loft - £28,834

Convert a basement - £35,637