Azar Construction Ltd · London builders
House extensions in London
Single and double-storey rear, side-return and wrap-around extensions, built by one coordinated team from foundations to final decoration.
Types of extension we build
Most London extensions fall into a handful of shapes. Which one suits your house depends on the plot, the existing structure and how you want to use the new space.
- Single-storey rear extensions to enlarge a kitchen, dining or living area.
- Side-return extensions, common on Victorian and Edwardian terraces, filling the narrow strip beside the rear outrigger.
- Wrap-around extensions that combine a rear and side-return extension into one large room.
- Double-storey extensions adding a bedroom or bathroom above a new ground-floor space.
Planning permission and permitted development
Many single-storey rear extensions can be built under permitted development, typically up to 3 metres deep on a terraced or semi-detached house and 4 metres on a detached house. Larger single-storey extensions can use a prior approval route, which involves your neighbours being consulted.
Permitted development rights do not apply to flats and maisonettes, and they are restricted in conservation areas and on listed buildings. Some boroughs also remove them with an Article 4 direction. We can coordinate with your architect, but planning decisions always rest with the local authority, so check before you commit to a design.
Building regulations and party walls
An extension almost always needs Building Regulations approval, whether or not it needs planning permission. That covers foundations, structural steelwork, drainage, insulation, ventilation and fire safety. A building control inspector visits at set stages and signs off the completed work.
If you are building on or next to a shared boundary, or excavating close to a neighbouring building, the Party Wall etc. Act 1996 may require you to serve notice on your neighbours before work starts. We coordinate party wall surveyors and structural engineers rather than leaving you to find them.
What is included in the work
- Groundworks, foundations and drainage.
- Brickwork or blockwork, structural steel, roof structure and roofing.
- Glazing, bi-fold or sliding doors and rooflights.
- First and second fix, plastering and making good to the existing house.
- Kitchens, flooring, joinery and decoration where they are in the agreed scope.
Every project starts with a site visit and a written, itemised quotation that sets out scope, exclusions and provisional sums. Variations are priced and approved in writing before they are built. See how we work.
Common questions
Many single-storey rear extensions can be built under permitted development, but flats, conservation areas, listed buildings and Article 4 areas are treated differently. The local planning authority makes the decision, so confirm with the council or a planning consultant before building.
Yes, almost always. Building Regulations apply even where planning permission is not needed. A building control inspector checks the work at key stages and issues a completion certificate.
Usually, yes. We phase the work, dust-seal the areas you are living in and agree working hours with you. Where a kitchen is being replaced, we plan temporary facilities with you first.
It depends on size, structure, glazing and finish, so we do not quote from a web page. After a site visit you receive a written, itemised quotation with scope, exclusions and validity period.
Related services
We work across Greater London and, by arrangement, the Home Counties. See areas we cover or read our verified reviews on Checkatrade.
This page is general information, not structural, planning or legal advice. Rules depend on your property and local authority. See our disclaimer.