From £87,048
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in City Of Westminster. No obligat...
From £87,312
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £87,200
Relax... you have found a reliable extension builder in City Of Westminster. Derryard Construction Ltd is a friendly and reliable company based in ...
From £86,968
B J CULLEN BUILDERS are here to help customers who need an Extension Builder in City Of Westminster. We offer a competitive rate to complete all yo...
From £87,032
Relax... you have found a reliable extension builder in City Of Westminster. Major Building Contractors Ltd is a friendly and reliable company base...
From £87,184
Need to find an Extension Builder near you for all your extension buildering work?
Sz Builders provides a local, trusted extension builderi...
From £87,712
Experienced extension builder ready to quote for your work. Render is the best extension builder in City Of Westminster. No obligation free quotes ...
From £86,896
Experienced extension builder ready to quote for your work. Jhon is the best extension builder in City Of Westminster. No obligation free quotes an...
From £86,880
Member since August 2025
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £87,192
NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...

Building a granny annexe ranges from £86,880 (Can design and Construction based in Ig11) to £87,712 (Render based in IG1), but these are just estimates that can help give you an idea of who will be better value in your area.
The best thing to do is to get quotes to build a granny annexe in City Of Westminster by posting a job with HaMuch. We will send it to extension builders in City Of Westminster who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near London | £45 | £274 |
| Granny Annexe near Camden Town | £44 | £277 |
| Granny Annexe near Belgravia | £44 | £276 |
| Granny Annexe near Chelsea | £44 | £276 |
| Granny Annexe near Lambeth | £44 | £275 |
| Granny Annexe near Kensington | £44 | £277 |
| Granny Annexe near Islington | £45 | £276 |
| Granny Annexe near Fulham | £44 | £277 |
| Granny Annexe near Camberwell | £44 | £276 |
| Granny Annexe near Bethnal Green | £45 | £276 |
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 - £17,642

Two storey extension - £88,214

Build a timber frame extension - £26,142

Build a swimming pool - £81,142

Single storey extension - £57,848

Side return extension - £43,102

Install an RSJ - £2,342

Outbuilding - £10,142

Build a Mansard loft conversion - £52,142

Loft conversion - £35,085

Build a kitchen extension - £42,142

Hip to gable loft conversion - £42,142

Granny annexe - £87,142

Garden office - £10,142

Convert a Garage - £16,142

Garage - £18,642

Build a flat roof extension - £22,142

Build a dormer loft conversion - £42,142

Concrete foundations - £6,392

Convert a bungalow loft - £29,142

Convert a basement - £39,102