How much to build 4 flats?

Four flats cost noticeably more per square metre to build than one house of the same size, and that gap is what catches most small developers. Every requirement that barely registers on a house becomes a line item across a block. Communal circulation is floor area you build, heat and maintain but cannot sell. Fire regulations mean protected stairs, compartmentation between units and alarm systems well beyond domestic spec. Acoustic separation has to pass Part E sound testing, not just look right on a drawing.

Then the planning obligations arrive. CIL charges, Section 106 contributions, and on some schemes pressure for affordable housing provision. Developers who price the job like a big house and discover these later are the ones whose sites stall half-built. Feasibility has to come first: what the flats will sell for, minus build cost, fees, finance and obligations, and whether what is left justifies the risk.

The alternative is conversion. Turning an existing building into flats keeps the structure, the roof and usually the service connections, and takes most of the groundworks out of the equation. The compliance work still has to be done properly (fire, acoustics, separate services), but you start from a building rather than a hole. All Well renovates and extends existing buildings across South London rather than developing from the ground up, and from that side of the fence, conversion is where small schemes most often stack up.