Wraparound extensions

A wraparound extension combines a side return infill with a rear extension to make an L-shaped addition that wraps around the back corner of the house. It creates the largest possible open-plan space on the ground floor of a terraced or semi-detached home.

Because it involves both a side and a rear element, a wraparound usually needs a householder planning application in England, and it almost always involves the Party Wall Act. Structurally it is more involved too, with steelwork to carry the corner where the two old walls meet.

What is included

• Survey, design and 3D layout options
• Householder planning application
• Party wall notice support (England and Wales)
• Structural design for the corner and openings
• Foundations, drainage and any manhole relocation
• Roof with glazing along the side return
• Full internal finish or kitchen-ready shell

Who it suits

• Terraced houses that want the largest ground floor possible
• Semi-detached houses with a side passage
• Families who want kitchen, dining and living in one space

Design advice

The corner is where wraparounds succeed or fail. We usually use a single steel goalpost or a corner post hidden in a pier, and set the glazing so the new room reads as one space rather than two boxes.

How much does it cost?

National guide prices including VAT at 20%. Build cost only; design, structural and council fees are extra. Your area page shows prices adjusted for your region.

Planning rules across the UK

England

In England a wraparound extension is assessed as both a side and a rear extension, and the combination usually falls outside permitted development, so most need a householder planning application (£548 from 1 April 2026).

Wales

In Wales a wraparound must satisfy both the rear and side extension limits to be permitted development, so most need a planning application to the council.

Scotland

In Scotland, householder permitted development rules (Class 1A for single-storey ground-floor extensions and Class 1B for extensions of more than one storey) allow some smaller extensions without a planning application, within limits on depth, height and distance from the boundary. Conservation areas and listed buildings are more restricted. Separately, almost every extension needs a building warrant from the council before work starts.

Northern Ireland

In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.

Building regulations and neighbours

Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

In England and Wales, if the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations. Scotland and Northern Ireland have no Party Wall Act.

Questions about wraparound extensions