How much does it cost to convert a house into flats?
Splitting a house into self-contained flats is priced largely per new unit created. Get an indicative per-flat figure below.
What a flat conversion involves
- 1Planning and rights
Converting a house into flats needs planning permission (and often building regs for fire and sound) — confirm before committing.
- 2Self-contained units
Each flat needs its own kitchen, bathroom, entrance and, ideally, separate services and meters.
- 3Fire and sound separation
Compartmentation between units (fire-rated floors/walls) and acoustic separation are core costs, plus a compliant escape strategy.
Splitting a large house into flats can lift total value well above the single-dwelling figure, which is why it's a favourite BRRR and add-value play. The economics live or die on planning, separate services and the fire strategy — cost all three in from the start.
House-to-flats conversion costs (indicative)
| Scope | Per unit | Notes |
|---|---|---|
| Studio / 1-bed flat | £20,000 – £35,000 | Kitchen, bathroom, services |
| 2-bed flat | £30,000 – £45,000 | Larger, more rooms |
| Sound & fire separation | included | Floors/walls between units |
| Typical house → 2 flats | — | £45,000 – £90,000 |
Per new self-contained unit. Planning, separate services/meters and a fire strategy are essential.
Frequently asked questions
How much does it cost to convert a house into flats?+
Budget roughly £20,000–£45,000 per new self-contained flat created, covering kitchen, bathroom, services, sound and fire separation and building control — so a house into two flats is often £45,000–£90,000, excluding purchase and professional fees.
Do I need planning to convert a house into flats?+
Yes — creating self-contained flats is a material change of use that needs planning permission, plus building regulations approval for fire compartmentation, sound insulation and means of escape.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.