Office to residential conversion under Class MA

Class MA prior approval turns a building in Class E use into dwellinghouses without a full planning application, provided the building qualifies and the council is satisfied on a short list of defined matters. It sits in Schedule 2 Part 3 of the General Permitted Development Order 2015, and it has been amended twice since it came into force in August 2021. Anyone working from a 2021 or 2022 summary is working from the wrong rules.

The route is attractive because the council cannot refuse on design, on housing mix, on affordable housing or on loss of employment floorspace. It is narrower than it looks because the qualifying conditions sit on the building rather than on the scheme, and because Class MA authorises a change of use and nothing else.

What Class MA permits

Class MA permits development consisting of a change of use of a building and any land within its curtilage from a use falling within Class E of the Use Classes Order to a use falling within Class C3, dwellinghouses.

Class E is wide. Shops, offices, professional services, restaurants and cafes, gyms, nurseries, medical and health services, light industrial and indoor recreation all sit inside it since the 2020 reforms. So the route is available to far more buildings than the shorthand "office to residential" suggests, including a former retail unit or a redundant health centre, subject to the specific prior approval matters that attach to some of those previous uses.

What Class MA does not do is authorise building work. No new windows, no dormers, no roof extension, no external staircase, no balconies, no rear extension. Those need separate permission, and on a deep-plan office building the fabric works are usually the difference between a scheme that produces decent flats and one that does not.

The conditions on the building

Two conditions run to the building itself rather than to the proposal.

The building must have been in Class E use, or in one of the uses now falling within Class E, for a continuous period of at least two years before the date of the application. That is a factual test and the council will ask for evidence. Business rates records, lease documents, accounts, dated photographs and utility bills all help, and a gap in occupation is not automatically a gap in use.

The second condition is the one that has changed. When Class MA was introduced the building also had to have been vacant for three continuous months, and the floorspace changing use could not exceed 1,500 square metres. Both were removed by amendment in March 2024. The two year use condition survives.

Class MA is also switched off entirely in defined circumstances, including listed buildings and scheduled monuments and several categories of designated and hazard land. Read paragraph MA.1 of the Order against the site before you spend money on measured surveys. And check the title, because an agricultural tenancy or a restrictive covenant can defeat a scheme that planning law would allow.

The prior approval matters

Prior approval under Class MA is limited to a defined list, and the council cannot stray outside it. The matters cover transport impacts and in particular safe site access, contamination risk in relation to the building, flooding risk in relation to the building, the impact of noise from commercial premises on the future occupiers, and the provision of adequate natural light in all habitable rooms. Where the building sits in a conservation area and the change of use affects a ground floor, the impact on the character or sustainability of that area comes in. Where the site is in an area the authority considers important for general or heavy industry, waste management, or storage and distribution, the impact on the intended occupiers is assessable. There are further matters where the building is in use as a registered nursery or provides health services.

That list tells you what to submit. A Phase 1 desk study addresses contamination for a site with an industrial history, and land contamination work has to be prepared by a suitably qualified and experienced person, so treat any draft as a starting point for that professional rather than a substitute. A Noise Impact Assessment deals with a building over a late-licensed unit or next to a servicing yard. A Flood Risk Assessment is needed where the building sits in Flood Zone 2 or 3, and a first floor and above conversion in Flood Zone 3 needs the vulnerability and safe access argument spelled out rather than assumed.

Transport is usually the shortest section and the one most often left thin. Say what the parking position is, where refuse is presented, how deliveries and removals will work, and what cycle storage is provided.

Natural light and space standards

Adequate natural light in all habitable rooms is a prior approval matter, and it is the one that kills deep-plan office conversions. There is no single numeric test written into the Order, so authorities look at room depth, window area, orientation, outlook and whether any habitable room is served only by a rooflight or a light well.

Every dwelling created under Class MA must also meet the nationally described space standard. That covers minimum gross internal areas by number of bedrooms and bedspaces, minimum bedroom sizes and built-in storage. On a floor plate with a central core, the standard and the light test together usually set the unit count long before the client's spreadsheet does.

Draw the daylight case properly. A plan showing room depths, window head heights and a schedule of areas against the standard answers both points in one submission.

When a full application is the better route

Prior approval looks like the lower cost route. It is not always faster in practice, and it constrains what you can build.

Consider a full application where the scheme needs external alterations to work, where the building is listed or in a sensitive setting, where you want more units than the light and space tests allow under a use-only consent, or where the council has an Article 4 direction covering Class MA in that area. A full application also lets you argue design merit and put forward a Planning Statement that engages with the development plan, which a prior approval simply does not allow.

The trade-off is real. A full application brings affordable housing policy, biodiversity net gain and local plan housing standards into play, and on a scheme of ten or more units that changes the numbers substantially.

Fees, the clock and what to submit

Prior approval under Part 3 runs on a 56 day determination period from receipt of a valid application, under the general procedure in paragraph W. The authority may grant approval, refuse it, or notify you that prior approval is not required. If it does none of those within the period, the development may proceed in accordance with the details submitted, which is a right worth having but a poor thing to plan around.

Fees are set by the national fee regulations and are indexed, so check the current schedule rather than a figure quoted in an older article. Submit the plans, the evidence of the two year Class E use, the technical reports the prior approval matters call for, and a short covering statement that takes each matter in turn in the order the Order lists them. Case officers work through that list, and a submission organised the same way is validated faster.

Enter your postcode on PlanScope to see which reports a Class MA conversion on your building is likely to need before you submit.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it, and remember that a lawful development certificate is the only formal way to confirm that works or a use are lawful. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.