From £87,440
Need to find an Extension Builder near you for all your extension buildering work?
Main Construction provides a local, trusted extension bu...
From £87,008
Whites Carpentry & Building prides in delivering an excellent extension buildering service and value for money in RH20 and the surrounding areas. ...
From £86,872
Need an Extension Builder in RH20? MPS Home Improvements Ltd has been helping local clients (20 mile radius) with their extension buildering jobs f...
From £86,992
Member since August 2026
H P Building Services Sussex is a one-stop solution for all your extension buildering needs. Establish over 10 years ago and covering 20 miles arou...
From £87,168
R S Construction (Surrey) is an established extension buildering business in RH20. We come highly recommended and provide competitive quotes for yo...
From £87,032
We are a family run business we 40 years experience delivering multiple projects from new developments . Extension. Loft conversion. Including foun...
From £87,112
Futureways Design and Build are here to help customers who need an Extension Builder in RH20. We offer a competitive rate to complete all your exte...
From £87,200
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £87,376
Giles Dixon is an experienced Project Manager with over 30 years experience, having worked from the ground up starting in 1984 as an apprentice ele...
From £87,128
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

Building a granny annexe ranges from £86,872 (MPS Home Improvements Ltd based in RH14) to £87,440 (Main Construction based in BN12), 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 RH20 by posting a job with HaMuch. We will send it to extension builders in RH20 who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near Rustington | £36 | £246 |
| Granny Annexe near Littlehampton | £35 | £244 |
| Granny Annexe near Arun | £35 | £241 |
| Granny Annexe near Worthing | £35 | £251 |
| Granny Annexe near Lancing | £37 | £251 |
| Granny Annexe near Horsham | £38 | £265 |
| Granny Annexe near Shoreham-by-Sea | £36 | £250 |
| Granny Annexe near Bognor Regis | £35 | £247 |
| Granny Annexe near Burgess Hill | £36 | £240 |
| Granny Annexe near Chichester | £34 | £242 |
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 - £17,633

Two storey extension - £88,199

Build a timber frame extension - £26,133

Build a swimming pool - £81,133

Single storey extension - £57,656

Side return extension - £42,994

Install an RSJ - £2,333

Outbuilding - £10,133

Build a Mansard loft conversion - £52,133

Loft conversion - £34,995

Build a kitchen extension - £42,133

Hip to gable loft conversion - £42,133

Granny annexe - £87,133

Garden office - £10,133

Convert a Garage - £16,133

Garage - £18,633

Build a flat roof extension - £22,133

Build a dormer loft conversion - £42,133

Concrete foundations - £6,383

Convert a bungalow loft - £29,133

Convert a basement - £38,994