From £22,280
Member since August 2026
Relax... you have found a reliable extension builder in HP4. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in HP4 who cons...
From £22,280
Trusted and professional extension builder in HP4. Experienced in all extension buildering work and keeping within budget and on quote. DC Build & ...
From £22,312
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £21,920
NISUP BUILDING SERVICES Company specializes in the domestic and commercial building industry :1. Refurbishm...
From £22,432
Krystian Wojasiewicz is a trusted extension builder serving customers in HP4 and the surrounding area. Contact us to today to get a competitive quo...
From £22,432
Platinum Electrics is a Branch off Platinum Premier Projects who deal in all types of construction projects. Platinum Electrics are based in London...
From £22,112
Trusted and professional extension builder in HP4. Experienced in all extension buildering work and keeping within budget and on quote. D Dan Const...
From £22,184
Experienced extension builder ready to quote for your work. DIAL 1ST CONSTRUCTION LTD is the best extension builder in HP4. No obligation free quot...
From £22,160
Trusted and professional extension builder in HP4. Experienced in all extension buildering work and keeping within budget and on quote. PARKWAY MAI...
From £22,248
C & A Contractors is a trusted extension builder serving customers in HP4 and the surrounding area. Contact us to today to get a competitive quote ...

A flat roof extension ranges from the cheapest of £21,920 (Nisup Building Services based in HA8) to the dearest of £22,432 (Krystian Wojasiewicz based in HA9), but these are just estimates. While they give you an idea of who will be better value, the best way to compare costs is to get real quotes.
Find out how much your flat roof extension will cost in HP4 by posting a job with HaMuch. We'll send it to extension builders in HP4.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Build A Flat Roof Extension near Berkhamsted | £41 | £263 |
| Build A Flat Roof Extension near Dacorum | £42 | £269 |
| Build A Flat Roof Extension near Hemel Hempstead | £42 | £270 |
| Build A Flat Roof Extension near Chesham | £42 | £277 |
| Build A Flat Roof Extension near Dunstable | £41 | £272 |
| Build A Flat Roof Extension near Rickmansworth | £42 | £278 |
| Build A Flat Roof Extension near St Albans | £63 | £288 |
| Build A Flat Roof Extension near Harpenden | £86 | £315 |
| Build A Flat Roof Extension near Hazlemere | £40 | £272 |
| Build A Flat Roof Extension near Luton | £41 | £278 |
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 - £17,736

Two storey extension - £88,354

Build a timber frame extension - £26,236

Build a swimming pool - £81,236

Single storey extension - £59,720

Side return extension - £44,155

Install an RSJ - £2,436

Outbuilding - £10,236

Build a Mansard loft conversion - £52,236

Loft conversion - £35,963

Build a kitchen extension - £42,236

Hip to gable loft conversion - £42,236

Granny annexe - £87,236

Garden office - £10,236

Convert a Garage - £16,236

Garage - £18,736

Build a flat roof extension - £22,236

Build a dormer loft conversion - £42,236

Concrete foundations - £6,486

Convert a bungalow loft - £29,236

Convert a basement - £40,155