From £2,144
STYLE BUILDING SERVICES LTD are here to help customers who need an Extension Builder in Welwyn Garden City. We offer a competitive rate to complete...
From £2,624
Wiemy jak wa?n? decyzj? dla naszych Klientów jest budowa kupno czy remont domu, dlatego stawiamy na nowoczesne i ekonomiczne rozwi?zania , a ca?? ...
From £2,368
LBH Building & Property Services are here to help customers who need an Extension Builder in Welwyn Garden City. We offer a competitive rate to com...
From £2,680
We offer an extensive building service including a turnkey solution. We are experts in residential extensions, alterations and new builds in the He...
From £2,600
J&R Property is an established and experienced local extension builder in Welwyn Garden City. Please contact us for a free, no obligation quote and...
From £1,520
Complex Construction is an established extension buildering business in Welwyn Garden City. We come highly recommended and provide competitive quot...
From £2,408
NJG BUILDING SOLUTIONS LTD is an established and experienced local extension builder in Welwyn Garden City. Please contact us for a free, no obliga...
From £2,384
Lemsford Building is a trusted extension builder serving customers in Welwyn Garden City and the surrounding area. Contact us to today to get a com...
From £2,552
Trusted and professional extension builder in Welwyn Garden City. Experienced in all extension buildering work and keeping within budget and on quo...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Welwyn Garden City it ranges from £1,520 (Complex Construction based in AL7) to £2,680 (Herts Premier Builders based in AL7).
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 Welwyn Garden City by posting a job with HaMuch and we will send it to extension builders in Welwyn Garden City.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Welwyn Garden City | £42 | £268 |
| Install An RSJ near Hatfield | £64 | £283 |
| Install An RSJ near Hertford | £46 | £289 |
| Install An RSJ near Potters Bar | £43 | £273 |
| Install An RSJ near Harpenden | £86 | £315 |
| Install An RSJ near St Albans | £63 | £288 |
| Install An RSJ near Ware | £47 | £296 |
| Install An RSJ near Cheshunt | £48 | £285 |
| Install An RSJ near Stevenage | £44 | £282 |
| Install An RSJ near Hoddesdon | £46 | £296 |
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 - £17,637

Two storey extension - £88,205

Build a timber frame extension - £26,137

Build a swimming pool - £81,137

Single storey extension - £57,736

Side return extension - £43,039

Install an RSJ - £2,337

Outbuilding - £10,137

Build a Mansard loft conversion - £52,137

Loft conversion - £35,033

Build a kitchen extension - £42,137

Hip to gable loft conversion - £42,137

Granny annexe - £87,137

Garden office - £10,137

Convert a Garage - £16,137

Garage - £18,637

Build a flat roof extension - £22,137

Build a dormer loft conversion - £42,137

Concrete foundations - £6,387

Convert a bungalow loft - £29,137

Convert a basement - £39,039