More house.Fixed price.
Extensions and loft conversions across St Albans and Hertfordshire. Drawn by our own technologist, built by our own trades, and priced in writing before anything is ordered.
- TrustMarkRegistered business
- Federation of Master BuildersMember
- Customer rating4.9 from 186 reviews (all reviews shown)
- Public liability£5m cover
- Guarantee10 years, insurance-backed
Seven things we build, and what they usually cost.
Typical Hertfordshire prices for 2026, including VAT. Tap one to see your own range.
Single-storey rear
From £2,300 per m²A kitchen-diner out the back. Often permitted development.
Side return
From £2,500 per m²Fills the alley beside the kitchen. Narrow, so fiddly, so priced higher.
Wraparound
From £2,450 per m²Side return and rear in one go. One set of drawings, one build.
Double-storey
From £3,680 per m²A bedroom over the new kitchen. About 1.6 times single-storey cost, not double.
Loft dormer
From about £55,000A box on the back of the roof: a bedroom and a shower room.
Hip-to-gable loft
From about £62,000For hipped-roof semis. Squares off the side for full-height space.
Mansard loft
From about £78,000The most space from a roof. Usually needs planning permission.
Not sure which one?
That is what the free design visit is for. Ninety minutes, a laser measure, no pressure.
Book a visitSame house. More room.
Drag the divider. Every project we show has a fixed price and a real programme next to it.
A kitchen that finally faces the garden
The old kitchen was a galley at the front of a long, dark ground floor. Priya and Tom wanted one room that ran from the front door to the garden, with the children in sight while someone cooked.
- Size28 m² extension
- On site14 weeks
- RoutePermitted development
- Fixed price£96,400 inc. VAT
We were braced for extras. There were two, both quoted in writing the same day, both ones we asked for.
Eight stages, in this order, every time.
Nothing gets built before it has been drawn, calculated, agreed with the neighbours and priced.
- 1Design visitFree, 90 minutes
- 2Measured surveyWeeks 1 to 2
- 3Drawings, planning or LDCWeeks 2 to 7
- 4Structure and building regsWeeks 5 to 9
- 5Party wallAlongside, 2 months
- 6Fixed-price contractWeeks 10 to 11
- 7Build, weekly photos10 to 14 weeks
- 8Sign-off and guaranteeFinal week
No surprises is a process, not a slogan.
A fixed price, in writing
The contract states the drawings, the specification, the programme and the price. Provisional sums are named and capped. Anything you change is quoted before it is built.
You pay at stages, never up front
No deposit above 10%. Each payment is tied to a finished stage, and the last 5% is held until the snagging list is cleared.
The same team, start to finish
Our technologist draws it, our engineer partner calculates it and our own carpenters, bricklayers and plasterers build it. No strangers on your kitchen floor.
Our neighbour was nervous about the party wall. Ben walked her through the drawings in her own kitchen, and she signed the award within the week.
Priya and Tom, Harpenden. Rear extension, 2026The price on the contract was the price we paid. We added a rooflight halfway through and they quoted it the same day, in writing, before touching it.
Dan, Hatfield. Loft dormer, 2025Weekly photos on a Friday meant I never had to ring and ask. The plasterer even left the room tidy enough to eat in.
Chloe and Rob, Welwyn Garden City. Hip-to-gable, 2026Book a free design visit.
We come to your house for 90 minutes with a laser measure and a notebook. Within five working days you have a sketch idea and a price range in writing.
Choose a day Mon to Fri 8am to 5.30pm. 07700 900 247