Class MA prior approval: the limits and conditions

Class MA of the General Permitted Development Order 2015 allows commercial, business and service premises in use class E to change to dwellinghouses in class C3 without a full planning application, subject to prior approval. The qualifying conditions do most of the work, and Class MA prior approval requirements have been amended more than once since the right came into force in August 2021. Read the current consolidated text of Class MA before relying on any summary, including this one, because the floorspace ceiling and the vacancy condition have both been the subject of amendment.

What has stayed constant is the shape of the right. A qualifying building, in qualifying use for long enough, on land where the right is not excluded, with a closed list of matters the council may consider and nothing else.

What the right permits

Class MA permits the change of use of a building from class E to class C3. Class E is broad: shops, restaurants and cafes, financial and professional services, indoor sport and recreation, medical and health services, creches and day nurseries, offices, research and development, and light industrial processes that can be carried out in a residential area.

That breadth is the point. A building that has moved between several of those activities has remained in class E throughout, so the qualifying use clock has not been reset.

The right covers the change of use. It does not permit external alterations, extensions, new openings or changes to the roof, all of which need a separate planning application. It also comes with a condition requiring the development to be completed within three years of the date of prior approval.

The continuous use condition

The building must have been in class E use, or in one of the uses that preceded class E and was subsumed into it, for a continuous period of at least two years before the date of the prior approval application.

Evidence is what decides this. Leases and tenancy agreements, business rates records, utility accounts, filed accounts showing trading from the address, and dated photographs of signage all help. A building that has stood empty for most of the two years, or that has drifted into a sui generis use such as a hot food takeaway or a drinking establishment, will not qualify.

The vacancy condition, which required the building to have been vacant for a continuous period immediately before the application, is one of the provisions that has been amended. Check whether it applies to your application before you deliberately empty a building, because emptying it on the strength of an out of date article is an expensive mistake in either direction.

Floorspace, and why you must check it

The right was introduced with a ceiling on the floorspace that could change use, and that ceiling has been amended. Do not rely on a remembered figure.

Where a limit applies, measure the floorspace changing use rather than the whole building, and measure it consistently with the definition used in the Order. If a ground floor unit is being retained in commercial use and only the upper floors are converting, only the converting floorspace counts.

Where no limit applies, scale brings its own problems: a larger conversion is more likely to raise transport, amenity and fire safety issues within the prior approval matters, even though the council cannot refuse on general planning policy grounds.

Excluded land and buildings

Class MA does not apply to listed buildings or to buildings within their curtilage, or to scheduled monuments. It is also excluded on sites of special scientific interest, safety hazard areas and military explosives storage areas, and there are restrictions relating to agricultural tenancies.

Conservation areas are different, and this is the point most often misunderstood. The right is not withdrawn in a conservation area, but an additional prior approval matter applies concerning the impact of the loss of ground floor commercial use on the character or sustainability of the area. That gives the council a specific hook for a high street unit, and it is used.

Article 4 directions matter more than the exclusions. Many authorities have made directions removing Class MA across town centres, primary shopping areas and employment allocations. Check the authority's list of directions before anything else, because a direction ends the discussion.

The prior approval matters

The council may only consider the matters listed in the Order. They cover transport impacts, particularly on highway safety and on servicing and parking, contamination risks on the site, flooding risks, the impact of noise from commercial premises on the intended occupiers, the provision of adequate natural light in all habitable rooms, and, in a conservation area, the effect of losing a ground floor commercial use. Fire safety considerations apply to relevant buildings.

Three of these routinely decide applications.

Natural light is the most common reason for refusal on office conversions with deep floor plates. A room with no window, or with a window onto a lightwell that delivers almost nothing, will fail. Submit a daylight assessment with room by room results, not an assertion.

Noise from surrounding commercial uses is the second. Where the building sits above a pub, beside a takeaway extract or opposite a service yard, the council will want a Noise Impact Assessment showing internal noise levels against recognised criteria and the mitigation that achieves them. Mechanical ventilation will usually be needed so that windows do not have to be opened, which then interacts with overheating.

Contamination is the third, particularly on former light industrial or petrol filling station sites. A Phase 1 desk study is the starting point, and a contaminated land assessment prepared by a suitably qualified and experienced person is what an environmental health officer expects if a pollutant linkage is identified.

Space standards and the quality question

Dwellings created under Class MA must meet the nationally described space standard. That condition was introduced to stop the very small units that earlier office to residential conversions produced, and it is enforced through the prior approval.

Set the unit layouts against the standard early. A floor plate that yields eight units at the standard may have yielded eleven without it, and the viability of the scheme changes accordingly.

Take the interaction with overheating seriously as well. A sealed, mechanically ventilated flat on a south facing elevation can overheat badly, and an overheating risk assessment is worth doing at design stage rather than discovering the problem at building control.

When a full application works better

Prior approval is faster and the grounds for refusal are limited. It is also rigid. You cannot extend, you cannot add windows where the elevation needs them, and you cannot reconfigure the envelope to make the units work.

A full application is usually better where the building needs external alteration to produce decent homes, where the site is in an area covered by an Article 4 direction, where the scheme would benefit from a mix that includes larger family units, or where the building is listed. It also allows a design led scheme that adds a storey or reworks the ground floor, which prior approval never will.

Run the test on the floor plans. If the units only work with new openings, you are looking at a planning application whether you like it or not.

Check the Article 4 position, pull the rating and lease history for the two year test, and get a daylight study done on the worst floor before spending anything else. You can also see which supporting reports a conversion usually needs before you commission the survey work.

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