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Select your affordable Cardiff extension builder
From £88,360
Lewis Jones
Member since October 2026
We are polite, punctual and respectful small construction business. We take pride in all our work.
The Philog Paving Services is an established extension buildering business in Cardiff. We come highly recommended and provide competitive quotes fo...
Experienced extension builder ready to quote for your work. Chapman Builders is the best extension builder in Cardiff. No obligation free quotes an...
Experienced extension builder ready to quote for your work. JA Building Maintenance is the best extension builder in Cardiff. No obligation free qu...
Experienced extension builder ready to quote for your work. TOR BUILD is the best extension builder in Cardiff. No obligation free quotes and many ...
Relax... you have found a reliable extension builder in Cardiff. Charles Marshall Contracting Ltd is a friendly and reliable company based in Cardi...
Bill Coslett
35 years in the trade and there is not much we haven't come across or done from pools to extensions and we specialise in loft conversions
MARWAY BUILDING LTD is a trusted extension builder serving customers in Cardiff and the surrounding area. Contact us to today to get a competitive ...
Cardiff, CF5
Trusted and professional extension builder in Cardiff. Experienced in all extension buildering work and keeping within budget and on quote. Elite B...
Paul Knox
Trusted and professional extension builder in Cardiff. Experienced in all extension buildering work and keeping within budget and on quote. PK CONS...

Costs range from £86,560 (PK CONSTRUCTION based in CF14) to £88,360 (L.Jones Building based in CF62), but these are just estimates. The best way to compare costs is to get real quotes from real builders.
Post your job on HaMuch and we'll send it to extension builders to Cardiff.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Two Storey Extension near Cardiff | £34 | £223 |
| Two Storey Extension near Penarth | £35 | £224 |
| Two Storey Extension near Caerphilly | £33 | £208 |
| Two Storey Extension near Barry | £33 | £223 |
| Two Storey Extension near Church Village | £34 | £214 |
| Two Storey Extension near Risca | £32 | £218 |
| Two Storey Extension near Newport | £41 | £233 |
| Two Storey Extension near Pontypridd | £33 | £211 |
| Two Storey Extension near Cwmbran | £43 | £219 |
| Two Storey Extension near Weston-super-Mare | £33 | £253 |
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 - £17,121

Two storey extension - £87,431

Build a timber frame extension - £25,621

Build a swimming pool - £80,621

Single storey extension - £47,416

Side return extension - £37,234

Install an RSJ - £1,821

Outbuilding - £9,621

Build a Mansard loft conversion - £51,621

Loft conversion - £30,195

Build a kitchen extension - £41,621

Hip to gable loft conversion - £41,621

Granny annexe - £86,621

Garden office - £9,621

Convert a Garage - £15,621

Garage - £18,121

Build a flat roof extension - £21,621

Build a dormer loft conversion - £41,621

Concrete foundations - £5,871

Convert a bungalow loft - £28,621

Convert a basement - £33,234