From £21,944
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 £22,424
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 £22,168
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 £22,480
We offer an extensive building service including a turnkey solution. We are experts in residential extensions, alterations and new builds in the He...
From £22,400
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 £21,320
Complex Construction is an established extension buildering business in Welwyn Garden City. We come highly recommended and provide competitive quot...
From £22,208
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 £22,184
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 £22,352
Trusted and professional extension builder in Welwyn Garden City. Experienced in all extension buildering work and keeping within budget and on quo...

A flat roof extension ranges from the cheapest of £21,320 (Complex Construction based in AL7) to the dearest of £22,480 (Herts Premier Builders based in AL7), but these are just estimates. While they give you an idea of who will be better value, the best way to compare costs is to get real quotes.
Find out how much your flat roof extension will cost in Welwyn Garden City by posting a job with HaMuch. We'll send it to extension builders in Welwyn Garden City.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Build A Flat Roof Extension near Welwyn Garden City | £42 | £268 |
| Build A Flat Roof Extension near Hatfield | £64 | £283 |
| Build A Flat Roof Extension near Hertford | £46 | £289 |
| Build A Flat Roof Extension near Potters Bar | £43 | £273 |
| Build A Flat Roof Extension near Harpenden | £86 | £315 |
| Build A Flat Roof Extension near St Albans | £63 | £288 |
| Build A Flat Roof Extension near Ware | £47 | £296 |
| Build A Flat Roof Extension near Cheshunt | £48 | £285 |
| Build A Flat Roof Extension near Stevenage | £44 | £282 |
| Build A Flat Roof Extension 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