Project Overview
This was one of the most complex projects we've taken on. The brief was to take down the existing semi-detached house completely and build a new home on the same plot, with a wraparound extension that effectively doubled the floor area.
The job went well beyond the house itself. The whole building and garden were lowered by half a metre, and the garden was reshaped from scratch into a Chelsea-style landscape to suit the new home.
Demolition, Rebuild and a Wraparound Extension
Replacing the house entirely gave the owners a home designed around how they wanted to live, rather than one adapted around an existing layout. The wraparound extension wraps the rear and side of the property, which creates the space for a much larger ground floor and brings in light from more than one direction.
Lowering the House and Garden by Half a Metre
Dropping the entire site by 0.5 metres meant careful excavation and levelling across the footprint and the garden. It also meant planning drainage and the relationship with neighbouring ground levels. Lowering the site gave the new house better proportions and more generous ceiling heights. It also let the garden flow straight out from the ground floor.
An Open-Plan Ground Floor Built on Complex Structural Work
The ground floor is one large open-plan space. Spans like that don't happen without serious structural engineering, and a lot of the steelwork and support that holds it up is hidden once the finishes go on. Underfloor heating runs through the entire ground and first floors, so there are no radiators breaking up the walls.
Architectural Details and Finishes
The centrepiece is a glass and metal staircase. It's joined by shadow gaps throughout the house and a range of architectural, structural and decorative features. These details only look effortless when the work underneath is accurate, and no corners were cut at any stage of the build.
Challenges and How We Handled Them
A project of this scale rarely runs without complications, and this one had several. Work was paused for a month in the early stages while issues with neighbours were resolved. As the build progressed, changes were made to structural elements and the owners added further modifications, which pushed the programme back.
Some of the work was also carried out by separate trades appointed directly by the owners, outside the Combit team. Coordinating several independent contractors on one site brought extra time pressure and cost. Keeping the build organised took a lot of hands-on management from Igor and the team.
Signed Off and Handed Over
Despite the setbacks, the house was completed with all required tests and certificates signed off. The owners have a home that looks stunning and is built to last.
Scope of Works
- Full demolition of the existing semi-detached house
- New build with wraparound extension
- Lowering of the house and garden by 0.5m
- Complex structural works for an open-plan ground floor
- Underfloor heating across ground and first floors
- Glass and metal staircase
- Shadow gaps and architectural detailing
- Chelsea-style garden landscaping
New Builds in Mill Hill and Across North London
We've been building across North London since 2006, from extensions and renovations to complete new build homes. Our clients rate us highly on Google and Houzz. Every project comes with a detailed, itemised quote and clear written sign-off on any variations. We also provide aftercare once we've handed over.
Planning a New Build in Mill Hill?
If you're thinking about knocking down and rebuilding, or taking on a large-scale extension in Mill Hill or nearby, try our Project Cost Calculator. Enter a few details to get an initial estimate, then book a consultation with Igor and the team.
Frequently Asked Questions
Do I need planning permission to demolish and rebuild a house?
In most cases, yes. Replacing a house usually needs full planning permission from your local council, and changes to ground levels can also form part of the application. The Planning Portal is a good starting point, and we can guide you through the process.
Does the Party Wall Act apply when rebuilding a semi-detached house?
Yes. Demolishing and rebuilding a semi-detached house involves work on or near a shared wall, so you'll need to serve notice on your neighbour under the Party Wall etc. Act 1996. Getting this right early helps avoid delays once work starts.
Is it better to extend or rebuild?
It depends on the condition of the existing house, how much extra space you want and what your plans allow. Where you'd be changing most of the structure anyway, rebuilding can give you a better layout and a more efficient home for a similar outlay.
Why use one builder for the whole project?
With one team responsible from demolition to handover, there's a single point of accountability for the programme, the budget and the quality of the finish. Splitting work across separate contractors often leads to gaps in responsibility, delays and extra cost.