Flat conversion drawings in the City of London

Almost no houses, almost no gardens

Only 2 per cent of City households live in a house, and domestic gardens cover 0.1 per cent of the land in the national land-use survey. A garden-sharing question simply does not arise. Outdoor space for a new home therefore has to be a balcony or terrace, tested against Min 5 m² private outdoor space for 1-2 person dwellings plus 1 m² per extra occupant, min 1.5 m deep and wide.

Space is the real constraint, and the standards leave little room: Minimum GIA: 1b1p 39 m² (37 m² with shower), 1b2p 50 m², 2b3p 61 m², 2b4p 70 m² (one-storey dwellings); 3b4p 74 m², 3b5p 86 m². Rooms are held to Single bedroom at least 7.5 m² and 2.15 m wide; double at least 11.5 m², one double at least 2.75 m wide (others 2.55 m). The London height rule is 2.5 m, which tends to rule out low mezzanines in older buildings.

Owner-occupation is 36.5 per cent and the average house price is £710,652, so a conversion is judged by what each unit adds to a high-value market.

Route, fee and the council's record

Where one dwelling becomes two, planning permission is needed: Use of a single dwellinghouse as two or more dwellings is a material change of use. Where an office becomes homes, a different route may apply, which is a question for our planning drawings in the City of London. The national fee for creating homes is £610 per dwelling.

The City decided 173 minor applications in its latest year, granted 97.1 per cent and decided 93.1 per cent in time. Householder decisions are almost non-existent, just 1 in the year, so the minor-application figures are the better guide to how the team works.

What a City conversion looks like in practice

Three kinds of job arrive. The first is a flat in a residential block, often the Barbican, where an owner wants to move a wall or change a kitchen and the management guidelines decide what is allowed. The second is a flat above a shop or office, in a listed or conserved building, where a new layout has to respect the original structure. The third is an office or storage floor that is being turned into homes.

For the second kind, access is the first issue. Many upper floors are reached by a narrow stair shared with a commercial tenant, and a new residential use needs its own entrance, a protected escape route and a place for refuse. Those are fixed by the building and often cannot be improved, so we check them before designing a layout.

For the third kind, the key test is the quality of the homes. Deep floor plates have little daylight, and the space standards leave no slack. We run a daylight and layout check early, and where a floor will not support two decent flats we say so and suggest one.

The City decided 477 planning decisions in total in its latest year, so each application tends to be read closely and individually. We build each set with that in mind.

Levy, sound and price

The City also charges its own CIL, which differs between the riverside and the rest of the City, and the Mayoral charge sits in band 1 at £96.97 per square metre, indexed. The small-build exemption is lost for a new home: The under-100 m² CIL exemption does not apply where a new dwelling is created.

In a dense building the neighbours are close, so sound matters: Separating walls 43 dB DnT,w+Ctr (min); floors and stairs 43 dB airborne (min), 64 dB L'nT,w impact (max) for dwellings formed by material change of use. Our building regulations drawings in the City of London set out the build-ups.

Flat conversion drawings start at £1,195, VAT included, with free redraws after council comments and no promise of a decision. See architectural drawings in the City of London, or compare flat conversion drawings in Westminster on the other side of the boundary.