04 / 15 Construction & conversions
A well-planned extension gives you the space you need without the cost and upheaval of moving: a bigger kitchen, a family room that opens onto the garden, or extra bedrooms upstairs. We are extension builders who handle the whole job, from the survey and approvals to the foundations, the structure and the finished room.
Because our team also includes electricians, plumbers, heating engineers, tilers and decorators, your extension is finished by the same company that built it, with one quote and one point of contact from start to finish.
Types
Many Victorian and Edwardian terraces have a narrow passage down the side of the rear wing. A side return extension builds over that passage, usually with a glazed roof or rooflights, turning a narrow galley kitchen into a wide, bright room.
See our side return extension page
A wrap-around extension combines a side return and a rear extension in one L-shaped build. It creates the largest single-storey open-plan space, usually a kitchen, dining and living area across the whole back of the house.
See our wrap-around extension page
A double-storey extension adds space on two floors at once, typically a larger kitchen or living room downstairs and one or two bedrooms or a bathroom upstairs. Because it shares one set of foundations and one roof, it usually gives more space for the money than two separate projects.
See our double-storey extension page
A single-storey extension at the rear of the house, designed around a new kitchen, often with an open-plan dining area, bifold or sliding doors and rooflights. It is the most common extension we are asked about.
See our kitchen extension pageNot sure which?
Every house is different — we check what suits yours before you commit to anything.
Book a free extension surveyWhich suits your home
| Type of house | Options we usually look at first |
|---|---|
| Victorian or Edwardian terrace with a rear wing | Side return or wrap-around extension |
| Terrace or semi without a side passage | Single-storey kitchen extension at the rear |
| Semi-detached or detached with space to the side | Double-storey side or rear extension, or a kitchen extension |
| Family needing more bedrooms and a bigger kitchen | Double-storey extension |
| Conservation area or listed building | Any type, subject to planning permission and design approval |
This is a starting point. The right choice depends on your plot, how you want to use the space, your budget and what your council allows.
What you need to know
Many single-storey extensions on houses in England can be built under permitted development, without a planning application, provided they stay within set limits. The main ones are:
Double-storey extensions, wrap-around extensions and most side returns on terraces usually need a planning application, because they combine side and rear elements or go above one storey. Permitted development does not apply to flats and maisonettes, and it is restricted in conservation areas, for listed buildings and where an Article 4 direction applies. We tell you at the survey which route your extension needs and prepare the drawings for it.
What you need to know
You can build up to the boundary, but it affects both the design and the paperwork:
What you need to know
Every extension needs building regulations approval, whether or not it needs planning permission. Building control inspects the work at key stages and issues a completion certificate at the end. The main areas are:
If the extension is built over or within 3 metres of a public sewer, you will usually need a build over agreement from the water company. We check the sewer maps before the design is finished.
What you need to know
Most extensions on terraced and semi-detached houses involve the Party Wall etc. Act 1996, because foundations are dug near the neighbouring house or the new wall is built on the boundary. You must give your neighbours written notice before this work starts. If they agree, work can go ahead; if not, a party wall surveyor prepares an award. We tell you at the survey whether notices are needed and build the time into the programme.
Cost
Every extension is priced after a free survey, and you receive a written, itemised quote. These are the main factors:
A double-storey or wrap-around extension costs more in total than a single-storey rear extension, although building two floors at once often gives better value per square metre.
Clay soil, nearby trees and drains can mean deeper or specialist foundations.
The number and size of steel beams needed to open up the back of the house.
Bifold or sliding doors, rooflights and glazed roofs are a significant part of the cost.
Units, worktops, appliances and sanitaryware, plus the plumbing and tiling to install them.
Extending radiators or adding underfloor heating.
Narrow side passages or no rear access can mean materials are carried through the house.
Drawings, structural calculations, planning, building control and party wall costs where they apply.
No guesswork: you receive a written, itemised quote after your free survey, with payments staged against clear points in the work.
Timescale
A single-storey kitchen or side return extension is usually the quickest. Wrap-around and double-storey extensions take longer, because there is more structure and more to finish inside. Before building starts, allow time for drawings, planning or prior approval where needed, building regulations approval and any party wall notices. Your quote includes a programme showing each stage and how long it should take.
09 — One team
An extension needs many trades. We coordinate all of them:
If you want to update the rest of the kitchen or house at the same time, see our kitchen renovation service.
New circuits, sockets, lighting and smoke alarms through our domestic electrical installation service.
Warm floors under large glazed areas through our underfloor heating installation service, or new radiators.
Sinks, dishwashers and appliances connected through our kitchen plumbing service.
Kitchen floors and splashbacks through our kitchen and bathroom tiling service.
Plastering and painting, so the room is ready to use on handover.
Process
Every stage is planned before we start, with one project manager from survey to sign-off.
we look at the house, the garden, the boundaries and access, and talk through what you want the new space for.
drawings and structural calculations are prepared, and you receive an itemised quote with a programme.
planning permission or prior approval where needed, building regulations approval, party wall notices and any build over agreement.
the site is set up, foundations are dug and inspected, and drains are laid.
walls, steel beams, roof and glazing. The existing house is kept weathertight until the new space is closed in.
the back of the house is opened up, wiring and pipework are run, and then plastering, flooring, kitchen fitting, tiling and decorating follow.
building control completion, electrical and other certificates, and a walk-round of the finished extension.
Areas
We build extensions across London, with a focus on east and south-east London. The Victorian and Edwardian terraces of East Ham and parts of Ilford suit side return and wrap-around extensions, the interwar houses of Dagenham and Barking often suit single-storey rear kitchen extensions, and Orpington's semis and detached homes, with their wider plots, often suit double-storey extensions. See our pages for builders in Ilford, builders in East Ham, builders in Dagenham, builders in Barking and builders in Orpington, or all the areas we cover.
FAQs
Can't see your question? Call or WhatsApp us — we're happy to help before you book.
It depends mainly on the size and type of extension, the foundations, the amount of glazing and the kitchen or bathroom fit-out. Single-storey extensions cost less in total, while double-storey extensions usually give better value per square metre. We give you a fixed, itemised quote after a free survey.
Not always. Many single-storey rear and side extensions on houses fall under permitted development if they stay within size, height and position limits. Double-storey and wrap-around extensions, extensions to flats, and most work in conservation areas need planning permission. We check your property at the survey.
A single-storey kitchen or side return extension is usually the quickest to build, and wrap-around and double-storey extensions take longer. Time for drawings and approvals comes before the build. Your quote includes a programme showing each stage.
You can build up to the boundary. Under permitted development, any part within 2 metres of it must have eaves no higher than 3 metres. A wall on the boundary line needs your neighbour's agreement, and party wall notices are usually required.
Usually, yes. Most of the work happens outside until the new space is closed in and the back of the house is opened up. The kitchen may be out of use for part of the project, and we plan a temporary kitchen area with you where needed.
They solve different problems. An extension adds ground-floor living space, such as a larger kitchen, while a loft conversion adds bedrooms without using any garden. If you have an unused garage, a garage conversion can be a lower-cost alternative. We can advise on the best option at the survey.
One team, every trade
Next step
Tell us about your house and the space you need. We will visit, explain what your council is likely to allow and send you a written, itemised quote.
Send us photos of the back of your house on WhatsApp to get started, or use our contact form.
