Construction drawings in Merton

Heritage in Merton and what it does to a specification

Merton has 28 conservation areas and 243 Historic England list entries, and its heritage data records 23 entries on the Heritage at Risk Register. Some streets are therefore sensitive to the choice of window and brick, even where no listed building stands.

The set records the choices that heritage officers look at: window material and glazing bars, roof covering, brick and mortar colour. It also shows how each new element still meets the energy standard: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4.

If a design still needs planning consent, planning drawings in Merton establish the scheme first. We then draw the technical set to the letter of the decision.

Large rear extensions and what a notification may leave open

For a large single-storey rear extension, Merton's published statistics show 22 prior approval notifications granted and 80 refused. The ratio is a reminder that neighbours' comments and the council's reading of impact decide the outcome, and not every notification passes.

Notification or not, the technical set is the same job. A kitchen extension still needs foundations suited to the ground, a structural opening, and a roof build-up that reaches the limit in the national table. Where the opening is wide, we show the beam, its bearings and the temporary support, and structural calculations in Merton feed those details.

Stairs, loft access and escape in a Merton house

Merton's loft work meets the same stair rules as anywhere else. The geometry building control checks is Private stair: rise 150-220 mm, going 220-300 mm, max pitch 42°, 2R+G 550-700 mm, and headroom is 2.0 m clear headroom over stairs. In a semi with a narrow hall, the stair often decides whether the loft is a bedroom and a bathroom or only a bedroom.

A loft bedroom also needs an escape window: Escape window: unobstructed openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of opening no more than 1100 mm above floor. We draw the window position against the roof slope and the rafters to check it can be reached before the dormer or roof-light order is placed.

Timing, checks and what to read next

The council decided 759 householder applications in its latest published year and granted 92.9 per cent, although only 85.2 per cent were decided in time. A start date should therefore carry some slack, and the set should be ready before the decision arrives. Ordering steel, windows and roof lights early is where a finished set pays for itself, because lead times for each differ and the order can be placed from one schedule.

The fee is fixed after a free constraints check, and every sheet is checked by a second chartered technologist. For the set sent for approval, see building regulations drawings in Merton, and for the whole borough architectural drawings in Merton. Nearby, the same service is available in Sutton and Kingston upon Thames.