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 £86,872
Need an Extension Builder in Southwick? MPS Home Improvements Ltd has been helping local clients (20 mile radius) with their extension buildering j...
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 £87,032
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 Southwick. We offer a competitive rate to complete all your...
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 £86,880
Trusted and professional extension builder in Southwick. Experienced in all extension buildering work and keeping within budget and on quote. Stret...
From £86,728
Need to find an Extension Builder near you for all your extension buildering work?
Knights Construction provides a local, trusted extension...
From £86,768
Trusted and professional extension builder in Southwick. Experienced in all extension buildering work and keeping within budget and on quote. Paul ...
From £86,984
Need to find an Extension Builder near you for all your extension buildering work?
FMB CONSTRUCTION LTD provides a local, trusted extension...

Building a granny annexe ranges from £86,728 (Knights Construction based in BN18) 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 Southwick by posting a job with HaMuch. We will send it to extension builders in Southwick who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near Shoreham-by-Sea | £36 | £250 |
| Granny Annexe near Lancing | £37 | £251 |
| Granny Annexe near Brighton | £35 | £251 |
| Granny Annexe near Brighton and Hove | £35 | £251 |
| Granny Annexe near Worthing | £35 | £251 |
| Granny Annexe near Burgess Hill | £36 | £240 |
| Granny Annexe near Rustington | £36 | £246 |
| Granny Annexe near Haywards Heath | £35 | £256 |
| Granny Annexe near Littlehampton | £35 | £244 |
| Granny Annexe near Mid Sussex | £35 | £261 |
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 - £17,501

Two storey extension - £88,001

Build a timber frame extension - £26,001

Build a swimming pool - £81,001

Single storey extension - £55,016

Side return extension - £41,509

Install an RSJ - £2,201

Outbuilding - £10,001

Build a Mansard loft conversion - £52,001

Loft conversion - £33,758

Build a kitchen extension - £42,001

Hip to gable loft conversion - £42,001

Granny annexe - £87,001

Garden office - £10,001

Convert a Garage - £16,001

Garage - £18,501

Build a flat roof extension - £22,001

Build a dormer loft conversion - £42,001

Concrete foundations - £6,251

Convert a bungalow loft - £29,001

Convert a basement - £37,509