We design and build single storey, double storey, side-return and wrap-around extensions across North London. One site manager runs the job from structural drawings through to the final coat of paint.
One site manager, in-house trades and a written fixed price agreed before we start. Fully insured and covered by a written workmanship guarantee.
Call 07969 378509Guide ranges for 2026, based on the way we price work across Barnet, Haringey, Camden and Islington. Every job is priced properly after a free site survey, and the figure we write down is the figure you pay.
£2,600 to £3,400 per m²
A 20 m² rear extension with bi-folds and a plastered shell typically lands between £52,000 and £68,000 before kitchen units.
£3,000 to £3,800 per m²
Narrow access, more steelwork and more roof per square metre, so the rate sits above a simple rear box.
£95,000 to £150,000
Rear and side combined on a typical Victorian terrace, including structural openings into the existing house.
£2,900 to £3,600 per m²
Adding a bedroom above the ground floor spreads the foundation and roof cost across two floors.
£3,500 to £7,000
Measured survey, drawings, planning or lawful development application, structural calculations and building control.
£1,200 to £2,400 per neighbour
Only needed where a neighbour does not consent in writing after notice is served.
North London
Spend Around £74,000 including the kitchen
Programme 14 weeks on site
North London
Spend Around £62,000
Programme 12 weeks on site
How we work
We visit, measure up and email a fixed-price quote within 24 hours. No day rates, no hidden extras.
In-house architectural drawings, structural calculations and planning applications handled for you.
One site manager oversees the job from start to finish, with weekly progress updates and a tidy site.
We fix every snag before final payment and back the work with a written workmanship guarantee.
Get a quote
Send the postcode and job type. A site manager will call back with a clear, itemised price.
Call 07969 378509Pick the closest one, we can fine-tune on the call.
Most single storey rear extensions work out between £2,600 and £3,400 per square metre, so a 20 square metre extension usually sits between £52,000 and £68,000 before kitchen units. Side-return and wrap-around builds cost more per square metre because of the extra steelwork and roof area. We give a fixed written price after a free site survey.
Many single storey rear extensions fall under permitted development, though we usually recommend a lawful development certificate for a future sale. Larger, side and double storey extensions, and anything in a conservation area, normally need full planning permission from Barnet, Haringey, Camden or Islington. We check this before any design work starts.
A single storey rear extension is typically 10 to 14 weeks on site. Wrap-around and double storey builds usually run 16 to 22 weeks. Design and planning before that takes a further 8 to 12 weeks if a full application is needed.
In most cases yes. We phase the work so you keep a working kitchen and bathroom for as long as possible, dust-seal the opening into the existing house, and agree access and working hours with you before we start.
Drawings, structural calculations, building control, groundworks, structure, roofing, glazing, electrics, plumbing, plastering and decoration. Kitchens, bathrooms and flooring are priced as separate itemised lines so you can see exactly what you are choosing.
Customer reviews
The quality of service offered by Haim, our first contact, has been highly impressive. Every aspect of your service has been beyond reproach, courteous, polite and reliable. Great work done on our house!
You've been a great help. Your service is fantastic. I'm so glad I picked you guys.
Thanks for all your hard work on my flat. True professionalism. Highly recommended.
Thanks a million to you and your team, we are VERY impressed with the service and will spread the word whenever we can.
We had a rear extension and full kitchen fit-out. The programme was realistic, the site was kept tidy and the final bill matched the quote.
Loft conversion done in nine weeks. One site manager who answered the phone every time and sorted the building control sign-off for us.
Straightforward from the first survey. Clear itemised pricing, no surprise extras, and the plastering and decorating finish is excellent.
Dormer, hip-to-gable and mansard lofts that add a bedroom and value.
Ground-up residential and commercial builds, on time and on spec.
Dig-outs and basement builds that add a full floor of usable space.
Full-house refurbs covering structure, electrics, plumbing and finishes.
Bespoke kitchens fitted by a single site-managed team.
Wet rooms, family bathrooms and en-suites, watertight and warrantied.
Group companies
Buying a site, funding a project or building it out, our partner companies cover the parts of the job that sit either side of construction.
Property development and real estate investment across London, from site acquisition to completed scheme.
hozeinvestment.co.ukDevelopment finance, bridging and mortgage advice for homeowners, landlords and developers.
eldorium-finance.co.uk