House Extensions in Harefield & West London
Single, double-storey and wrap-around extensions that add the space, and the light, your home has been missing.
Get a free quote
A few details and we'll be in touch, usually within one working day.
Extensions, designed and built as one.
An extension is the most reliable way to add genuine living space to a home you already love. We design the right footprint for your plot and your street, engineer it properly, and finish it so the new space feels original, not bolted on.
- Single, double-storey, wrap-around and side-return
- Kitchen and open-plan living extensions with steel structure
- Planning, permitted development and building regs handled
- One project-managed team from groundworks to snagging
House Extensions services
Single-storey extensions
Rear and side extensions that open up the ground floor.
Double-storey extensions
Adding bedrooms and bathrooms above new living space.
Wrap-around & side-return
Reclaiming the side return on period terraces for full-width rooms.
Kitchen & open-plan
Knock-throughs and glazed extensions built around how you live.
Design & build
Drawings, structural engineering and build under one contract.
Planning & permitted development
We advise on consent and prepare the applications for you.
Recent house extensions
House Extensions across the region
A few of the areas we cover for house extensions. See all 36 on our areas page.
How your project runs
Consultation & survey
We visit your home, understand your brief and take the measurements that make a quote meaningful.
Design & planning
Drawings, structural engineering and planning or building-regs applications, handled for you.
Build
One project-managed team on site, tidy, communicative and accountable from strip-out to snagging.
Handover & aftercare
A clean finish, your completion pack, and a workmanship guarantee that stands behind the work.
It depends on size, structure and finish. A single-storey rear extension typically starts well into five figures, with double-storey and wrap-around projects costing more. We give a clear, written quote after a survey.
Many extensions fall under permitted development, but size, height and conservation status all matter. We advise early and prepare any planning or building-regs applications for you.
Most single-storey extensions take around 10–16 weeks on site, depending on groundworks, structure and finish. We give you a programme before we start.
A well-designed extension that improves how the whole house works usually adds value, particularly kitchen and open-plan projects. We design for liveability first, which is what buyers pay for.
Yes. We can take a project from first sketch through structural engineering, planning and construction under one accountable team, so there are no gaps between designer and builder.
From the Journal
How Much Does a House Extension Cost in West London? (2026 Guide)
What a house extension really costs in West London in 2026, including the price drivers, the extras people forget, and when you need planning permission.
Loft Conversion or Rear Extension: Which Adds More Value?
Loft conversion or rear extension? A straight comparison of cost, disruption, planning and value to help you pick the right way to add space to your home.
Planning house extensions?
Tell us about your project and we'll arrange a survey and a clear, written quote.