CASE STUDY · APPROVED

Single-storey rear extension to a detached house

Roper Crescent, Sunbury-on-Thames · Spelthorne Borough Council

A flat-roofed single-storey rear extension to a two-storey detached house, adding 53.8 sqm for a larger lounge and dining area, with internal alterations. We prepared the existing and proposed drawings and the Design and Access Statement for the householder application.

Rear of the existing house and garden (Design and Access Statement)
Rear of the existing house and garden (Design and Access Statement)

The site

The site is a two-storey detached house in residential (C3) use in a recently developed estate of detached, semi-detached and terraced houses with generous gardens. It is in an SSSI impact zone, has no identified surface-water flood risk, and is about 360 m from a grade II listed building. There was no previous planning history for the property.

The challenge

The extension was large: up to 5 m deep, with an enlarged footprint. It had to stay subordinate to the house, keep enough garden, and avoid overbearing or overshadowing the neighbouring house under the 25° and 45° tests in the council's 2011 extensions SPD.

What was submitted

  1. Design and Access StatementThe extension replaces the existing shed and projects 5 m at its deepest and 2.34 m at its shallowest, adding 53.8 sqm. The required 70 sqm of garden amenity space is kept (SPD paragraph 3.30).
  2. Design and Access StatementThe neighbouring house to the west already extends further back, a 2.6 m gap is kept to the side, and the flat roof is 3 m high. The new side door is unglazed to protect privacy. The scheme was assessed against SPD paragraphs 3.4–3.59 and five similar approved schemes nearby.
  3. Existing and proposed ground floor planShows a 61.1 sqm lounge and 21.1 sqm dining area opening to the garden through bi-fold doors. A new study (7 sqm) and passage link the rooms, with fire exits, smoke detectors and a sprinkler marked.
  4. Existing and proposed front and side elevationsThe front elevation is unchanged. The side elevation shows the flat-roofed extension, with render finish to match the existing house and the existing first-floor terrace and roof retained.

Outcome

Spelthorne Borough Council granted conditional householder permission on 2 October 2024.

Images and findings are taken from the documents submitted with the planning application. The full application is available on the council's planning register.

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