Edmond Begu
EB Construction & Building Ltd are here to help customers who need an Extension Builder in HP3. We offer a competitive rate to complete all your ex...
Dave Reilly
BOXMOOR BLDG & CARP SERVICES is a trusted extension builder serving customers in HP3 and the surrounding area. Contact us to today to get a competi...
BARRETT LESLIE BUILDING are here to help customers who need an Extension Builder in HP3. We offer a competitive rate to complete all your extension...
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
Simon Johnson
Simon Johnson & Sons Builders are here to help customers who need an Extension Builder in HP3. We offer a competitive rate to complete all your ext...
Relax... you have found a reliable extension builder in HP3. GURNEY CONSTRUCTION is a friendly and reliable company based in HP3 who consider no jo...
Need an Extension Builder in HP3? JCG BUILDING SERVICES LTD has been helping local clients (20 mile radius) with their extension buildering jobs fo...
From £87,040
Trevor
Trusted and professional extension builder in HP3. Experienced in all extension buildering work and keeping within budget and on quote. T Woodman L...
From £87,080
WHITE HART BUILDING LIMITED is a trusted extension builder serving customers in HP3 and the surrounding area. Contact us to today to get a competit...
From £87,440
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 £86,896 (Simon Johnson & Sons Builders based in HP2) to £87,440 (Evolved Glazing Solutions Limited based in HP3), 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 HP3 by posting a job with HaMuch. We will send it to extension builders in HP3 who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near Dacorum | £42 | £269 |
| Granny Annexe near Hemel Hempstead | £42 | £270 |
| Granny Annexe near Berkhamsted | £41 | £263 |
| Granny Annexe near St Albans | £63 | £289 |
| Granny Annexe near Chesham | £42 | £277 |
| Granny Annexe near Rickmansworth | £42 | £278 |
| Granny Annexe near Watford | £43 | £278 |
| Granny Annexe near Harpenden | £87 | £317 |
| Granny Annexe near Bushey | £42 | £276 |
| Granny Annexe near Borehamwood | £42 | £271 |
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 - £17,649

Two storey extension - £88,223

Build a timber frame extension - £26,149

Build a swimming pool - £81,149

Single storey extension - £57,976

Side return extension - £43,174

Install an RSJ - £2,349

Outbuilding - £10,149

Build a Mansard loft conversion - £52,149

Loft conversion - £35,145

Build a kitchen extension - £42,149

Hip to gable loft conversion - £42,149

Granny annexe - £87,149

Garden office - £10,149

Convert a Garage - £16,149

Garage - £18,649

Build a flat roof extension - £22,149

Build a dormer loft conversion - £42,149

Concrete foundations - £6,399

Convert a bungalow loft - £29,149

Convert a basement - £39,174