From £10,048
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in UB9. No obligation free quotes ...
1 review
From £10,192
NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...
"Did callout made safe my elctrical work thanks" - reviewed 16/05/23, REECYRUSSO
From £10,392
Need an Extension Builder in UB9? Samuele Paolini has been helping local clients (5 mile radius) with their extension buildering jobs for many yea...
From £10,280
Member since August 2026
Relax... you have found a reliable extension builder in UB9. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in UB9 who cons...
From £10,192
Need an Extension Builder in UB9? VA Structures has been helping local clients (10 mile radius) with their extension buildering jobs for many years...
From £10,280
Trusted and professional extension builder in UB9. Experienced in all extension buildering work and keeping within budget and on quote. DC Build & ...
From £10,312
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £10,432
DP Services is a fully insured friendly local company which has been trading since 2002 and delivers high quality building work in domestic extensi...
From £10,152
I am a qualified, builder, electrician and plumber. I have been working in the construction industry for over 23 years and have built everything fr...
From £10,304
Hi we have 15 years of experience in building and construction industry our specialization is bathrooms and renovations please have a look at the w...

Outbuilding costs in UB9 range from the cheapest of £10,048 (J&J Building Solutions based in SW16) to the dearest of £10,432 (DP Services based in RG41), but these are just estimates.
Comparing extension builders estimates for building an outbuilding 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 build an outbuilding in UB9 by posting a job with HaMuch and we will send it to extension builders.
| Borough in London |
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| Outbuilding in Denham |
| Outbuilding in Hillingdon |
| Outbuilding in Gerrards Cross |
| Outbuilding in Uxbridge |
| Outbuilding in Ruislip |
| Outbuilding in Northwood |
| Outbuilding in Iver |
| Outbuilding in Rickmansworth |
| Outbuilding in Stockley Park |
| Outbuilding in Pinner |
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 - £17,758

Two storey extension - £88,388

Build a timber frame extension - £26,258

Build a swimming pool - £81,258

Single storey extension - £60,168

Side return extension - £44,407

Install an RSJ - £2,458

Outbuilding - £10,258

Build a Mansard loft conversion - £52,258

Loft conversion - £36,173

Build a kitchen extension - £42,258

Hip to gable loft conversion - £42,258

Granny annexe - £87,258

Garden office - £10,258

Convert a Garage - £16,258

Garage - £18,758

Build a flat roof extension - £22,258

Build a dormer loft conversion - £42,258

Concrete foundations - £6,508

Convert a bungalow loft - £29,258

Convert a basement - £40,407