House extension drawings in Merton

Prior approval in Merton: the council's own record

The record on larger home extensions is the clearest local signal. In its latest published year Merton granted 22 larger home extension prior approvals and refused 80.

Under that route the council looks only at the effect on neighbours, and it has 42 days to respond. Refusals outnumbering grants are a reason to talk to the neighbours first and draw their windows carefully. The national limit it applies to is: 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI.

For a smaller single-storey rear extension, the permitted development rule is 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey. A Lawful Development Certificate in Merton is the usual way to prove it.

Conservation areas, listed buildings and the constraints check

Merton has 28 conservation areas and 243 listed building entries. Inside a conservation area a side extension needs an application, and a listed house needs its own consent.

The borough has no Green Belt, at 0 per cent. Domestic gardens cover about 27.2 per cent of the land, and around 60.4 per cent of households live in a house, so a large share of Merton households have a house of their own to extend.

Our free constraints check reads your address against all of those layers and tells you the route before you pay for drawings.

What a Merton house costs, and what an extension does about it

The average detached house in Merton sells for around £2,338,085, a semi-detached house for £954,064 and a terraced house for £686,591. At those values a well-drawn extension is a decision worth getting right first time.

Cost is also about design time. A fixed-fee drawing set, priced before you commit, keeps the planning stage predictable even when the build budget is not.

How Merton decides householder applications

The council decided 759 householder applications in its latest published year, granted 92.9 per cent and decided 85.2 per cent within eight weeks or an agreed extension. The householder fee is £548, paid to the council.

Not every application is decided inside eight weeks, so allow for the full period and any agreed extension of time when you set a start date.

What the drawings include and what they cost

A Merton extension set shows existing and proposed floor plans, elevations and sections, with location and block plans, from one model. Drawings start at £695 with VAT included. A second MCIAT chartered technologist checks every sheet, and we redraw at no charge if the council asks for changes.

For the whole borough, see architectural drawings in Merton. For a single room at the back, rear extension drawings in Merton go through that case, and owners in Sutton or Wandsworth can compare nearby councils.