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A long row of Victorian brick terrace houses with bay windows, steps to the front doors and chimneys along the roofline

Flat conversion drawings from £1,095

Splitting a large house into two flats creates two homes, two front doors and a sound-proof floor between them. We draw each flat to the space standard and submit the planning application.

£1,095 £945 drawings + £150 survey (£1,095 total), no VAT to add

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The short answer

Flat conversion drawings show a house divided into two self-contained homes: both floor plans, the new entrances, the shared hall or stair and the sound and fire separation between them. Creating new dwellings needs planning permission. Our fee is £945 drawings + £150 survey (£1,095 total), no VAT to add, and the council fee is separate.

Flat conversion drawings (two flats)

from £1,095

Drawings
£945
Measured survey
£150
Total you pay
£1,095
VAT
None to add
  • A measured survey of every floor, the stair and the garden, with levels and window positions
  • Existing and proposed plans and elevations for both flats, with room sizes and floor areas marked
  • A check of both flats against the nationally described space standard and the council’s conversion policy
  • Bin, cycle store and garden arrangements drawn as officers expect to see them
  • The planning application, forms and the levy form, submitted for you
  • An independent check of every sheet, and free redraws of our drawings until approval

£945 drawings + £150 survey (£1,095 total). A starting fee: we confirm one fixed figure after checking your address. The council’s own fee, where there is one, is paid to the council.

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How a flat conversion runs with us

  1. Policy and lease check

    We read the council’s conversion policy, check for a minimum house size and an Article 4 direction, and ask about the lease or covenants.

  2. Survey

    Each floor is measured, along with floor-to-ceiling heights and the position of the existing stair and drains.

  3. Layouts

    We test a ground-floor-plus-garden flat and an upper flat, and show the floor areas against the standard.

  4. Planning application

    The drawings, statement, forms and fee go in, with the levy form where the council charges one.

  5. Technical set

    After the decision we draw the building regulations set, with sound and fire separation between the flats.

Planning: new homes need an application

A house in one dwelling is Class C3 under the Use Classes Order. Splitting it into two flats creates a second dwelling, which is development needing planning permission, not a right under permitted development. The council fee is set by the number of homes created, and the exact figure is on the GOV.UK fee schedule.

The questions an officer asks first are about the mix of homes in the area, parking, and whether each flat is big enough. Many councils resist conversions of smaller family houses, so we read the local policy before we draw.

How big must each flat be?

Councils use the nationally described space standard: 50 square metres for a one-bedroom, two-person flat, 61 square metres for a two-bedroom, three-person flat and 70 square metres for a two-bedroom, four-person flat, where each is on one level. Bedrooms are at least 7.5 square metres for a single and 11.5 for a double, and one double must be 2.75 metres wide.

We draw both flats with their areas on the plan, because the officer will measure them against the table. If the house cannot give two flats of that size, we tell you at the survey stage, before the fee for the application is spent.

  • 1 bedroom, 2 people: 50 m²
  • 2 bedrooms, 3 people: 61 m²
  • 2 bedrooms, 4 people: 70 m²
  • Double bedroom: 11.5 m², one at least 2.75 m wide

Sound, fire and the levy

Converting a house to flats is a material change of use under regulation 5, so the new floor between the flats must meet the sound rules for conversions in Approved Document E: airborne sound insulation of at least 43 dB and impact sound of no more than 64 dB. The floor build-up and the ceiling below are drawn to achieve it.

A flat conversion also creates a new dwelling, so it may be liable for the Community Infrastructure Levy even if it is under 100 square metres, where the council charges the levy (GOV.UK guidance). We include the levy forms with the application.

Fire strategy plan · CIL forms

Flat conversions in numbers

Questions about flat conversions

Is my house big enough for two flats?

Often a three-storey house is; a two-storey semi often is not. The test is whether each flat reaches the space standard with a sensible entrance and stair, and we answer that from the survey.

What about the lease or a freehold?

Splitting the title is a legal matter for a solicitor. Our drawings show the flats, and you can use them for the lease plans if you need them.

Do I need parking for each flat?

It depends on the council. Many London boroughs ask for car-free flats in areas with good public transport, and others have minimum standards. We read the policy and draw cycle parking either way.

Can I do this as a Lawful Development Certificate?

Not for a new dwelling, which needs planning permission. A certificate suits permitted development such as an extension.

See whether your house can become two homes

Send the address and a floor plan if you have one. We reply with the route and a fixed fee, from £945 drawings + £150 survey (£1,095 total).

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