Documents needed for a Class MA office to flats conversion
Class MA prior approval turns on a short list of prescribed matters, and natural light to habitable rooms is the one that sinks deep office floorplates. Here is the evidence pack that answers each of them.
A Class MA prior approval for an office to flats conversion is assessed against a closed list of matters, which makes the document pack more predictable than a planning application and less forgiving. The authority can only consider what Class MA lets it consider, and the item that defeats most deep office floorplates is the requirement for adequate natural light in all habitable rooms.
Get that one wrong and no amount of supporting material rescues it. Get it right and the rest is a matter of producing the information the prescribed matters call for, in a form the case officer can read in an afternoon.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. A Lawful Development Certificate is the only formal way to confirm that works are lawful.
The conditions that have to be met first
Class MA sits in Part 3 of Schedule 2 to the General Permitted Development Order 2015, and it only applies where the building qualifies. Check the qualifying conditions before you spend anything on drawings.
The building has to have been in a use falling within Class E of the Use Classes Order for a continuous period of at least two years before the date of the prior approval application. That condition has been in Class MA since it was introduced, and it is the one most often missed on a building that changed hands recently.
Class MA has been amended since it came into force, and the floorspace cap and the vacancy requirement that applied at the outset were removed in March 2024. Read the current consolidated text on legislation.gov.uk rather than an article or a summary, because the conditions have moved more than once.
The exclusions still bite. Listed buildings and scheduled monuments and land within their curtilage are outside Class MA, as are sites of special scientific interest, safety hazard areas, military explosives storage areas, and land in a National Park, the Broads, a National Landscape or a World Heritage Site. A building in a conservation area is not excluded outright, but the loss of a ground floor use in a conservation area is itself one of the prescribed matters.
Every new dwelling created has to meet the nationally described space standard. That is a condition, not a consideration, so a scheme with a studio below the standard fails whatever the daylight evidence says.
Natural light in every habitable room
The prescribed matter is the provision of adequate natural light in all habitable rooms of the dwellings. In practice this is an assessment question, and authorities expect it answered with modelling rather than assertion.
What works is a room-by-room assessment covering every habitable room, with the metric named, the modelling assumptions stated, and the results tabulated against the criterion used. Common approaches use average daylight factor or the illuminance criteria in the current British Standard on daylight in buildings, and some authorities publish a preference. Ask at the outset which they will accept.
The design responses that make a deep plan work are all about geometry. Reduce room depth relative to window head height. Introduce a lightwell or an internal courtyard. Place bathrooms, stores and circulation in the middle of the plan so no habitable room is landlocked. Increase window area where the elevation allows, and remember that a window into a deep recess or an internal atrium may not deliver what a plan drawing suggests.
A Daylight and Sunlight Assessment prepared to BRE 209 principles is the usual document, and councils expect a suitably qualified author, so professional review is strongly advised. Where a room cannot achieve the criterion, the honest answer is to change the plan. A statement arguing that the occupier will accept a dark bedroom does not survive contact with a case officer.
Noise, contamination and flood information
Three of the prescribed matters are environmental, and each has a proportionate answer.
Noise is about the impact of noise from commercial premises on the intended occupiers. On a high street or in a mixed building this needs a measured assessment rather than a desk study: plant on adjoining roofs, deliveries, extraction from a restaurant below, and late-night uses nearby. A Noise Impact Assessment using the relevant British Standard method for internal noise levels, with a glazing and ventilation specification that achieves them, is the document that closes this matter. Be careful about ventilation: a specification relying on closed windows has to work with the overheating strategy as well.
Contamination is about risks to the intended occupiers. For a purpose-built office on a site with no industrial history, a desk study and site walkover is often enough. Where the building sits on a former industrial site, or where soft landscaping or basement works are proposed, a phased investigation follows. A Land Contamination assessment must be prepared in accordance with the relevant British Standard by suitably qualified and experienced persons, and PlanScope's draft is a starting point for that professional rather than a substitute.
Flooding is about risk to the building and its occupiers. Check the flood map for planning first. In Flood Zone 2 or 3 the assessment has to address finished floor levels, safe access and egress, and the behaviour of the building in a flood event, and a conversion with residential use at ground floor in Flood Zone 3 is a hard case. A vulnerability change from commercial to residential is the point the authority focuses on.
Transport, refuse and the practical details
Transport impacts are a prescribed matter, and for a conversion the argument is usually favourable. The building already generates trips as an office, and residential use in a town centre location typically generates fewer vehicle movements across the day.
Say that with evidence. A short transport statement comparing the previous office trip generation with the proposed residential generation, using a recognised trip rate source, is proportionate and persuasive. Cover parking, including any parking the office had and what happens to it, cycle parking provision against the local standard, and servicing.
Refuse is not itself a prescribed matter in every reading, but it sits within the practical assessment and it is a frequent cause of questions. Show the bin store, its capacity against the authority's own requirements, and the drag distance from the store to the collection point. A scheme with 20 flats and a bin store reached through the building's only staircase will be queried.
Also resolve the mundane items on the drawings: post, meters, cycle store access, and where the residential entrance sits in relation to any retained commercial use. Mixed use buildings with one shared lobby cause management problems later.
Fire safety and the Building Safety Act position
The fire statement requirement under Article 9A of the Development Management Procedure Order 2015 attaches to applications for planning permission for relevant buildings, so a prior approval under Class MA does not trigger it in the same way. That does not mean fire safety can wait.
For a building of 18 metres or more, or seven storeys or more, the higher-risk regime under the Building Safety Act 2022 applies at building control stage, with the gateways and the Building Safety Regulator involved. A conversion of that height is a project where fire engineering input is needed early, and a Fire Statement or fire strategy requires someone with the necessary fire-engineering competence. PlanScope's draft is a starting point for that professional, not a substitute for them.
Even below those thresholds, means of escape from upper-floor flats in a building designed as an office is frequently the hardest technical problem in the conversion, and it drives the plan. Resolve it before the daylight modelling, because a new protected stair changes every floorplate.
What Class MA cannot deliver
The route is narrow by design, and that cuts both ways.
The authority cannot require affordable housing, because there is no planning obligation attached to a prior approval. It cannot apply its local plan policies on amenity space, parking standards, carbon reduction or design quality, because those are not prescribed matters. And it cannot refuse on the principle of losing the office floorspace, except through the narrow industrial-area consideration and the conservation area ground floor consideration.
For an investor that is the attraction. It is also why authorities have made Article 4 directions removing Class MA in particular areas, and why you should check for one before doing anything else.
Two further points. The Community Infrastructure Levy can still apply to new dwellings created through permitted development where a charging schedule is in force, so check the schedule and the notice requirements. And development granted by a development order sits outside the biodiversity gain condition, although you should confirm the current exemptions rather than assume. A comparison with the full application route is set out in our note on which reports a pub to residential conversion needs, where no prior approval route is available.
Preparing the prior approval submission
Assemble the pack in this order, because each item constrains the next.
- Evidence of Class E use for the required period: leases, rating records, accounts, photographs, and the planning history.
- Confirmation that no exclusion applies and no Article 4 direction removes the right.
- Existing and proposed plans with every habitable room labelled and dimensioned, and areas set against the space standard.
- Natural light assessment, room by room, with the metric and assumptions stated.
- Noise assessment with a glazing and ventilation specification.
- Contamination desk study, and further investigation where the history requires it.
- Flood risk information where the site is in Flood Zone 2 or 3.
- Transport comparison, parking, cycle provision and refuse strategy.
The authority has 56 days from a valid application to determine it, and development must not begin before either prior approval is given or that period expires without a determination. Submit a complete pack, because an incomplete one restarts the clock.
Enter your postcode on PlanScope to see which supporting documents your building is likely to need before you commit to the conversion.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
How long must a building have been in Class E use before a Class MA application?
A continuous period of at least two years immediately before the date of the prior approval application. Evidence usually means leases, business rates records, accounts and dated photographs alongside the planning history. Class MA has been amended since it came into force, so read the current consolidated text of Part 3 of Schedule 2 rather than a summary.
What counts as adequate natural light for Class MA?
There is no single prescribed figure, so authorities assess it on the evidence submitted. Most expect a room-by-room daylight assessment naming the metric used, commonly average daylight factor or the illuminance criteria in the current British Standard, with modelling assumptions stated. Ask the authority which approach it accepts before commissioning the work.
Can the council require affordable housing through Class MA?
No. Prior approval under Class MA is assessed against a closed list of prescribed matters and carries no planning obligation, so affordable housing, amenity space standards, parking standards and local carbon policies cannot be imposed. That is why some authorities have made Article 4 directions removing the right in particular areas, which you should check first.
Does a Class MA conversion need a fire statement?
The Article 9A fire statement requirement attaches to applications for planning permission for relevant buildings rather than to prior approval. For a building of 18 metres or seven storeys or more, the higher-risk regime under the Building Safety Act 2022 still applies at building control stage, and fire engineering input should be obtained early because escape routes drive the plan.
How long does the council have to decide a Class MA application?
Fifty-six days from a valid application. Development must not begin before the authority gives prior approval or that period expires without a determination being issued. An incomplete submission can restart the clock, so it is worth checking the local requirements and the fee position before submitting rather than afterwards.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.