From £87,560
Our homes need to be regularly maintained and from time to time they need to be rejuvenated, modernised and enhanced. When it comes to building wor...
From £86,984
JK Doors is a trusted extension builder serving customers in Upminster and the surrounding area. Contact us to today to get a competitive quote for...
From £87,192
NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...
From £87,312
skilled worker who specializes in completing a wide range of building and renovation projects
From £87,616
HOUSE BUILDING SERVICES LIMITED is a trusted extension builder serving customers in Upminster and the surrounding area. Contact us to today to get ...
From £86,888
Member since April 2025
Trusted and professional extension builder in Upminster. Experienced in all extension buildering work and keeping within budget and on quote. GR MA...
From £87,200
Relax... you have found a reliable extension builder in Upminster. Derryard Construction Ltd is a friendly and reliable company based in Upminster ...
From £86,968
B J CULLEN BUILDERS are here to help customers who need an Extension Builder in Upminster. We offer a competitive rate to complete all your extensi...
From £87,032
Relax... you have found a reliable extension builder in Upminster. Major Building Contractors Ltd is a friendly and reliable company based in Upmin...
From £87,184
Need to find an Extension Builder near you for all your extension buildering work?
Sz Builders provides a local, trusted extension builderi...

Building a granny annexe ranges from £86,888 (GR MAINTENANCE LTD based in IG11) to £87,616 (HOUSE BUILDING SERVICES LIMITED based in DA16), 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 Upminster by posting a job with HaMuch. We will send it to extension builders in Upminster who will be happy to help you.
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 - £17,694

Two storey extension - £88,290

Build a timber frame extension - £26,194

Build a swimming pool - £81,194

Single storey extension - £58,872

Side return extension - £43,678

Install an RSJ - £2,394

Outbuilding - £10,194

Build a Mansard loft conversion - £52,194

Loft conversion - £35,565

Build a kitchen extension - £42,194

Hip to gable loft conversion - £42,194

Granny annexe - £87,194

Garden office - £10,194

Convert a Garage - £16,194

Garage - £18,694

Build a flat roof extension - £22,194

Build a dormer loft conversion - £42,194

Concrete foundations - £6,444

Convert a bungalow loft - £29,194

Convert a basement - £39,678