From £86,440
We are a family run Construction Company based in Penzance. We employ over 10 skilled local trade professionals with 2 apprentices as well. Residen...
From £86,664
Searle Construction are here to help customers who need an Extension Builder in TR18. We offer a competitive rate to complete all your extension b...
From £86,472
Trusted and professional extension builder in TR18. Experienced in all extension buildering work and keeping within budget and on quote. Marks main...
From £86,616
D.P.Hatley Building Services is an established extension buildering business in TR18. We come highly recommended and provide competitive quotes for...
From £86,528
Trusted and professional extension builder in TR18. Experienced in all extension buildering work and keeping within budget and on quote. D & S Buil...
From £86,904
At peninsula refurbishment we provide a service from start to finish with minimal hassle for the customer. The workmanship is always high priority,...
From £86,792
Need to find an Extension Builder near you for all your extension buildering work?
Samuel Winn Design & Build provides a local, trusted ext...
From £86,784
Need to find an Extension Builder near you for all your extension buildering work?
KPK Builders Ltd provides a local, trusted extension bui...
From £86,744
Trusted and professional extension builder in TR18. Experienced in all extension buildering work and keeping within budget and on quote. Jo Tracey ...
From £86,752
Jackson Developments provides an affordable, quality service for customers across Cornwall.We undertake all aspects of building work and can manage...

Building a granny annexe ranges from £86,440 (TGP Construction based in TR18) to £86,904 (Peninsula Property Refurbishments based in TR15), 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 TR18 by posting a job with HaMuch. We will send it to extension builders in TR18 who will be happy to help you.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Granny Annexe near St Ives, Cornwall | £27 | £188 |
| Granny Annexe near Camborne | £28 | £196 |
| Granny Annexe near Falmouth | £33 | £220 |
| Granny Annexe near Truro | £31 | £206 |
| Granny Annexe near Newquay | £32 | £230 |
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 - £17,170

Two storey extension - £87,504

Build a timber frame extension - £25,670

Build a swimming pool - £80,670

Single storey extension - £48,392

Side return extension - £37,783

Install an RSJ - £1,870

Outbuilding - £9,670

Build a Mansard loft conversion - £51,670

Loft conversion - £30,653

Build a kitchen extension - £41,670

Hip to gable loft conversion - £41,670

Granny annexe - £86,670

Garden office - £9,670

Convert a Garage - £15,670

Garage - £18,170

Build a flat roof extension - £21,670

Build a dormer loft conversion - £41,670

Concrete foundations - £5,920

Convert a bungalow loft - £28,670

Convert a basement - £33,783