T.I Building is a trusted extension builder serving customers in BT17 and the surrounding area. Contact us to today to get a competitive quote for ...
From £1,536
Trusted and professional extension builder in BT17. Experienced in all extension buildering work and keeping within budget and on quote. Belfast Lo...
From £1,584
Relax... you have found a reliable extension builder in BT17. Finch Construction NI is a friendly and reliable company based in BT17 who consider n...
From £1,376
Trusted and professional extension builder in BT17. Experienced in all extension buildering work and keeping within budget and on quote. Extended l...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in BT17 it ranges from £1,376 (Extended living by Gilbert-Ash based in BT12) to £1,600 (T.I Building based in BT28).
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 BT17 by posting a job with HaMuch and we will send it to extension builders in BT17.
"RSJ installation" - BT17, job posted 01/01/70
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Lisburn | £24 | £164 |
| Install An RSJ near Belfast | £23 | £161 |
| Install An RSJ near Carryduff | £23 | £158 |
| Install An RSJ near Hillsborough and Culcavy | £25 | £170 |
| Install An RSJ near Maghaberry | £31 | £205 |
| Install An RSJ near Crumlin | £26 | £194 |
| Install An RSJ near Saintfield | £23 | £162 |
| Install An RSJ near Holywood | £23 | £159 |
| Install An RSJ near Comber | £22 | £160 |
| Install An RSJ near Ballynahinch | £19 | £189 |
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 - £16,824

Two storey extension - £86,986

Build a timber frame extension - £25,324

Build a swimming pool - £80,324

Single storey extension - £41,480

Side return extension - £33,895

Install an RSJ - £1,524

Outbuilding - £9,324

Build a Mansard loft conversion - £51,324

Loft conversion - £27,413

Build a kitchen extension - £41,324

Hip to gable loft conversion - £41,324

Granny annexe - £86,324

Garden office - £9,324

Convert a Garage - £15,324

Garage - £17,824

Build a flat roof extension - £21,324

Build a dormer loft conversion - £41,324

Concrete foundations - £5,574

Convert a bungalow loft - £28,324

Convert a basement - £29,895