From £17,548
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in HA6. No obligation free quotes ...
1 review
From £17,692
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 £17,892
Need an Extension Builder in HA6? Samuele Paolini has been helping local clients (5 mile radius) with their extension buildering jobs for many yea...
From £17,780
Member since August 2026
Relax... you have found a reliable extension builder in HA6. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in HA6 who cons...
From £17,692
Need an Extension Builder in HA6? VA Structures has been helping local clients (10 mile radius) with their extension buildering jobs for many years...
From £17,780
Trusted and professional extension builder in HA6. Experienced in all extension buildering work and keeping within budget and on quote. DC Build & ...
From £17,812
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,652
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 £17,804
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...
From £18,524
Buci builders ltd is a trusted extension builder serving customers in HA6 and the surrounding area. Contact us to today to get a competitive quote ...

Underpinning ranges from £17,548 (J&J Building Solutions based in SW16) to £18,524 (Buci builders ltd based in SE27), but the final cost will depend on the method of underpinning used, how much of your foundations need underpinning and where you live.
Comparing extension builders estimates for underpinning gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
Get quotes to underpin your home in HA6 by posting a job with HaMuch and we will send it to extension builders in HA6.
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 - £17,818

Two storey extension - £88,476

Build a timber frame extension - £26,318

Build a swimming pool - £81,318

Single storey extension - £61,352

Side return extension - £45,073

Install an RSJ - £2,518

Outbuilding - £10,318

Build a Mansard loft conversion - £52,318

Loft conversion - £36,728

Build a kitchen extension - £42,318

Hip to gable loft conversion - £42,318

Granny annexe - £87,318

Garden office - £10,318

Convert a Garage - £16,318

Garage - £18,818

Build a flat roof extension - £22,318

Build a dormer loft conversion - £42,318

Concrete foundations - £6,568

Convert a bungalow loft - £29,318

Convert a basement - £41,073