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 RH13? MPS Home Improvements Ltd has been helping local clients (20 mile radius) with their extension buildering jobs f...
From £87,328
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
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 £87,272
Need to find an Extension Builder near you for all your extension buildering work?
DPP Construction (David Price Partnership) provides a lo...
From £87,168
R S Construction (Surrey) is an established extension buildering business in RH13. 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
, BN18
Futureways Design and Build are here to help customers who need an Extension Builder in RH13. 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 £87,408
Garage Door Repairs is an established extension buildering business in RH13. We come highly recommended and provide competitive quotes for your wor...

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 RH13 by posting a job with HaMuch. We will send it to extension builders in RH13 who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near Horsham | £38 | £265 |
| Granny Annexe near Mid Sussex | £35 | £261 |
| Granny Annexe near Crawley | £38 | £255 |
| Granny Annexe near Burgess Hill | £36 | £240 |
| Granny Annexe near Haywards Heath | £35 | £256 |
| Granny Annexe near Horley | £38 | £258 |
| Granny Annexe near Shoreham-by-Sea | £36 | £250 |
| Granny Annexe near Lancing | £37 | £251 |
| Granny Annexe near Reigate | £40 | £270 |
| Granny Annexe near East Grinstead | £37 | £259 |
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 - £17,682

Two storey extension - £88,274

Build a timber frame extension - £26,182

Build a swimming pool - £81,182

Single storey extension - £58,648

Side return extension - £43,552

Install an RSJ - £2,382

Outbuilding - £10,182

Build a Mansard loft conversion - £52,182

Loft conversion - £35,460

Build a kitchen extension - £42,182

Hip to gable loft conversion - £42,182

Granny annexe - £87,182

Garden office - £10,182

Convert a Garage - £16,182

Garage - £18,682

Build a flat roof extension - £22,182

Build a dormer loft conversion - £42,182

Concrete foundations - £6,432

Convert a bungalow loft - £29,182

Convert a basement - £39,552