A modest rear extension can change how the whole ground floor works. At a home on Metcalfe Avenue in Carshalton, our design adds just 2.5 metres to the rear of the house, creating space for a garden-facing living area while reorganising the kitchen and dining space behind it.
Sutton Council granted householder planning permission on 21 April 2026, under application DM2026/00231. The approved proposal combines a shallow pitched roof, two rooflights and generous rear glazing, with brickwork and roof tiles chosen to match the existing house.
Giving each part of the open-plan space a purpose
The existing ground floor already brought cooking, dining and living into one connected space. The challenge was to make those activities sit more comfortably together. Moving the main seating area into the extension creates a clearer sequence through the house: kitchen, dining and then a place to relax overlooking the garden.
The proposed kitchen includes a peninsula with seats, providing somewhere to sit and talk without occupying the dining table. Full-height cupboards accommodate the fridge-freezer and oven, while a dining table with bench seating makes use of the space beside the kitchen. A shelving and library area adds another practical use along the route to the rear.
These details matter as much as the extra floor area. The design gives informal seating, everyday meals, storage and relaxation their own places within a shared room. The existing utility and WC remain near the entrance, keeping those functions separate from the new garden-facing living area.
Light from the roof and a stronger garden connection
Two rooflights are positioned over the extension to introduce daylight from above. At the rear, Crittall-style patio doors sit alongside full-height glazed panels with opening top sections. Together, these openings are intended to give the seating area an outlook towards the garden and bring light into the enlarged ground floor.
A wider opening through the original rear wall connects the extension to the rooms behind it. The drawings allow for the structural supports to be developed with the engineer, recognising that the feeling of openness depends on how the old and new parts of the house meet.
A low roof and a restrained footprint
The roof profile was a particular design consideration. The proposal uses a shallow 15-degree pitch, with eaves of approximately 2.7 metres and a maximum height of around 3.4 metres. This keeps the addition visibly below the main house while allowing a pitched roof and rooflights over the new room.
Limiting the projection to 2.5 metres also leaves more of the garden available beyond the extension. Matching brickwork and tiles help the addition relate to the existing building, while the glazed rear elevation gives the new living area its own character.
For this Carshalton home, the value of the proposal comes from combining a small extension with a more considered internal layout. If you are exploring a similar project, see our house extension design service or book a call to discuss how your ground floor could work better.
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