House extension drawings in Kingston upon Thames

Two-storey rear and side extensions

A two-storey rear extension may be acceptable on an end-of-terrace, semi-detached or detached house if the eaves line runs with the original and a minimum of 21 m is kept between the habitable-room windows of neighbours. The same daylight line of 45 degrees applies at first floor.

Side extensions are tested on separation. At least 15 m is asked between a primary elevation of an existing house and the flank wall of a two-storey side extension. For semi-detached and end-of-terrace houses the SPD asks for no more than half the original width, with 1 m gap; 500 mm set-down; 500 mm set-back.

Detached houses are treated differently: the roof of a side extension follows the existing roof or is set down, with 500 mm set-down; 1 m set-back. Where a house has a cat-slide roof, the first-floor side extension is set back 1 m from the front building line to keep it. Our double-storey extension drawings in Kingston upon Thames apply those tests house by house.

Green Belt, conservation areas and trees

About 17 per cent of the borough is Green Belt, and an extension inside it is judged on proportionality against the original house. The borough also has 28 conservation areas, 3 Article 4 directions and 163 listed building entries.

The council publishes 7,145 tree preservation zone areas. A mature tree near the back wall can change the foundation design or the position of the extension, so we locate trees at the survey, not after the first sketch.

Permitted development, prior approval and the borough's record

The national permitted development rule for a single-storey rear extension is 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey. That can be deeper than the SPD's guidance, so for a house with permitted development rights a Lawful Development Certificate in Kingston upon Thames can be a better route than a householder application.

The larger home extension route lets the council consider only the effect on neighbours. In its latest published year Kingston granted 3 such applications and refused 35. With refusals far outnumbering grants, the neighbour consultation deserves a straight conversation before you choose that route.

Householder decisions in Kingston upon Thames

The council decided 742 householder applications in its latest published year, granted 83 per cent and decided 92.5 per cent within eight weeks or an agreed extension. The fee for a single dwelling is £548.

About 61.5 per cent of households live in a house, and domestic gardens make up around 30.9 per cent of the borough's land. With that much garden land, the SPD's rule that half the rear garden must remain is a test every rear extension here has to pass.

What the drawings include and what they cost

A Kingston extension set shows existing and proposed floor plans, elevations and sections, with location and block plans, all from one model. Drawings start at £695 with VAT included and are checked by a second MCIAT chartered technologist. If the council asks for changes we redraw at no charge until approval.

For the borough as a whole, see architectural drawings in Kingston upon Thames. Owners just across the river should compare Richmond upon Thames, and those towards the south, Merton.