House extensions
House Extensions in Hertfordshire, Bedfordshire & London
An extension is often the best way to get the space your family needs without the cost and upheaval of moving. Whether it's a bigger kitchen-diner, an extra bedroom or a ground-floor space that opens onto the garden, we design and build extensions that feel like they were always part of the house.
More space without moving
We handle the whole project: drawings, planning or permitted development, structural calculations, building control and party wall matters, then the build itself — managed by one project manager from start to finish.
You get a fixed, itemised quote and a week-by-week programme before any work begins.
What's included
- Design and planning support with our architect partners
- Foundations, groundworks and drainage
- Steelwork and structural openings into the existing house
- Flat roofs with roof lanterns, or pitched roofs
- Windows, bi-fold and sliding doors
- Electrics, plumbing, heating and underfloor heating
- Plastering, flooring, decoration and kitchen fitting
- Building control sign-off
Options
Types of extension we build
Single-storey rear extensions
The most popular way to create an open-plan kitchen, dining and living space opening onto the garden.
Two-storey extensions
Add bedrooms upstairs and living space downstairs in one build — often better value per square metre.
Side-return extensions
Ideal for Victorian and Edwardian terraces, using the narrow side passage to widen the kitchen.
Wraparound extensions
Combining side-return and rear extension for the biggest possible ground-floor transformation.
Front & porch extensions
Smaller additions for a better entrance, cloakroom or storage.
Extension + renovation
Refurbishing the existing house at the same time as adding space.
Our process
How your project runs
1. Free site visit
We look at the space, listen to what you want and talk through budget and options.
2. Design & approvals
Drawings, structural calculations, and planning or permitted development where needed.
3. Fixed quote & programme
An itemised price and a week-by-week schedule before anything starts.
4. The build
Managed by one project manager, with regular updates and stage sign-offs.
5. Handover
Final walk-round, snagging, building control completion certificate and all your paperwork.
FAQs
Frequently asked questions
Do I need planning permission for an extension?
Many single-storey rear extensions can be built under permitted development. Two-storey, side and larger extensions usually need planning permission, and different rules apply to flats, listed buildings and conservation areas. We'll tell you which applies at the site visit.
How long does an extension take?
A typical single-storey rear extension takes around 10–14 weeks on site, and a two-storey extension 14–20 weeks, depending on size and specification.
Can we stay in the house during the build?
Usually yes. We keep the existing house sealed off from the work for as long as possible and plan the knock-through stage to keep disruption short.
Thinking about extending?
Book a free site visit and we'll talk through layout options, likely costs and whether you need planning permission.