House extension types: which suits your home?

Taha Simsek

5 hours ago

4 min read

Start with the space you need, then choose how to add it. A narrow kitchen may benefit more from extra width than a longer room. A shortage of bedrooms asks a different question from a missing place to eat together.

Three architectural models comparing rear, side return and wraparound extensions, with pale existing houses and terracotta additions. — Three ways to extend the same illustrative house. Existing buildings are shown in pale plaster and additions in terracotta.

Rear, side return and wraparound describe where an extension sits. Single-storey and double-storey describe its height. The terms overlap: a rear extension, for example, can have one or two storeys. The useful comparison is what each arrangement changes inside your home.

The plans below compare how each option changes the same illustrative house. Existing space is pale and added floor area is shown in warm clay.

Rear extension: add depth towards the garden

Axonometric concept of a single-storey rear extension beyond an existing rear wing, with the side return left open. — Rear: additional depth beyond the existing rear wing.

A rear extension projects beyond the back of the house. It can make room for a dining table or living area, bring the kitchen closer to the garden, or create a separate room where that suits the household better.

Look at the journey through the existing house as carefully as the new space. A deeper plan can leave the former rear room in the middle, further from daylight. Decide what that room will become, where light will reach it and how people will move through it. Keep enough usable garden for the way you spend time outside.

Ground floor: extra depth creates a dining area connected to the existing kitchen.

Side return extension: turn a narrow plan into a wider room

Axonometric concept of a single-storey side return extension filling the gap beside the existing rear wing. — Side return: additional width alongside the existing rear wing.

A side return extension fills the strip beside an existing rear wing, a familiar arrangement in many London terraced houses. It is a particular form of side extension. The gain is often width: enough to place a table beside a kitchen, improve circulation or bring previously awkward corners into use.

The strip may already bring daylight into the house, contain drains or provide access to the garden. Plan how those functions will be accommodated as part of the extension. Rooflights can help bring light into a widened space, but their position should respond to the rooms and work surfaces below. A small increase in floor area can change the layout substantially.

Ground floor: the side return becomes a dining area linking the kitchen and living room.

Wraparound extension: reconsider the whole ground floor

Axonometric concept of a wraparound extension joining a side return infill with an addition across the rear. — Wraparound: side and rear additions connected in one arrangement.

A wraparound combines side and rear additions. It is worth exploring when neither extra width nor extra depth alone resolves the brief, for example when you want a useful kitchen, a dining area and a comfortable route to the garden.

Use that flexibility to test the whole ground floor. Where will coats, laundry and storage go? Does a quieter room still have a place? Consider the existing walls being opened up and the roof junctions being created alongside the layout. Give the new rooms clear roles, while keeping the remaining rooms useful.

Ground floor: side and rear additions create connected dining and sitting areas beside the existing kitchen.

Double-storey extension: solve needs on two levels

Axonometric concept of a two-storey rear extension, showing the added volume on both floors in warm clay. — Two-storey rear: the height changes, while the extension remains at the back.

A double-storey extension adds accommodation on two floors. It can be a useful option when the ground-floor brief comes with a need for another bedroom, bathroom or workspace upstairs. The illustration shows a rear example; the term itself describes the number of storeys.

Start upstairs as well as down. Check how the landing reaches the new rooms, whether existing rooms retain useful proportions, and how the new roof meets the house. The additional height also changes the relationship with neighbouring windows and gardens. Compare the foundations, structure and work to the existing building as a whole when considering the budget.

First floor: the rear bedroom gains a workspace; the ground-floor footprint follows the rear example.

Compare two options against the same brief

Draw both options on the same measured plan and put furniture into them. Compare what everyday life would feel like, including:

The activity each new space makes possible.
The daylight, storage and circulation in the rooms you already have.
The garden and access you want to retain.
The alterations needed elsewhere in the house to make the layout work.

A compact extension paired with a better internal arrangement is worth testing alongside a larger addition. This makes the choice clearer before the design becomes too fixed.

Establish the planning route early

In England, the extension's name does not determine its planning route. Permitted development depends on the house, previous additions, the proposed dimensions and applicable restrictions. To qualify as permitted development, a combined side and rear enlargement must satisfy both sets of relevant limits. Some two-storey rear extensions can qualify; two-storey side extensions require a planning application. Building regulations are a separate approval process.

Check those conditions alongside the first options. Our planning guide below explains the next steps in more detail.

Bring your existing plans, a few photographs and two or three priorities to an initial conversation with TNCO. We can help compare the options and connect the design, planning and delivery decisions. Explore our services.