Class M: shops and takeaways to dwellinghouses

Class M shop to dwelling permitted development is the small-unit route, and its defining feature is the 150 m² ceiling. Part 3 Class M of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 permits a change of use to a dwellinghouse from specified retail, service and takeaway uses, together with the building operations reasonably necessary to make the conversion work. That second part is what separates it from Class MA, which permits the change of use but not the works.

The uses Class M starts from

Class M operates from a defined list rather than from a whole use class. It covers retail sale of goods, financial and professional services of the kind formerly found in a high street bank or estate agency, cafés and restaurants, betting offices, pay day loan shops and hot food takeaways, together with mixed uses combining one of those with a dwelling.

Two qualifications sit over the list.

The building must have been in a qualifying use on the date specified in the Order, or, if not in use then, when it was last in use. The use classes were restructured in 2020 and the Order was amended to follow, so read the current consolidated wording of Class M rather than a summary, including an older summary of your own.

And the previous use has to be evidenced, not asserted. Business rates records, the lease, trading accounts, photographs and the authority's own planning history are the usual material. A unit that drifted from a shop into storage years ago may no longer qualify.

The 150 square metre limit

The floor space of the existing building changing use must not exceed 150 m², and the limit is cumulative. A previous Class M conversion in the same building counts against the allowance, so a 90 m² ground floor converted three years ago leaves 60 m² rather than a fresh 150.

Measure it properly, from the existing building rather than from the proposed layout, and state the basis of measurement in the application. Where the unit sits a little over the line, three routes exist.

• Convert part of the unit and retain the rest in its existing use, which keeps the figure inside the limit but creates a mixed building with shared access to resolve.
• Use Class MA instead, which starts from the commercial, business and service class and has its own conditions on previous use, set out in the note on Class MA vacancy and continuous use conditions.
• Apply for planning permission, which is slower but allows a design the prior approval matters would never accommodate.

Building works permitted alongside the change

This is the practical advantage of Class M. The class permits building operations reasonably necessary to convert the building, which covers the installation or replacement of windows, doors, roofs and exterior walls, and of water, drainage, electricity, gas and other services, to the extent needed for the building to function as a dwellinghouse. Partial demolition to the extent reasonably necessary to carry out those operations is included.

What that allows in practice: taking out a shopfront and replacing it with a residential frontage, forming new window openings, re-roofing, adding a rear door and installing a full services package.

What it does not allow: extending the building, adding a storey, changing its footprint or raising its height. Anything of that kind needs a separate permission, and combining a Class M prior approval with a planning application for an extension is a common and workable sequence as long as the two are not interdependent.

The word doing the work is "necessary". A frontage replacement is necessary. A rear terrace is not.

The prior approval matters

Before beginning development, the developer must apply to the local planning authority for a determination as to whether prior approval is required on a defined list of matters. The authority cannot refuse on anything outside the list, which is the discipline that makes the route attractive and the reason applications fail when they ignore it.

The list covers transport and highways impacts, contamination risks, flooding risks, the impact of losing the existing use on the adequate provision of local services where there is a reasonable prospect of the building continuing to provide them, the effect in a designated key shopping area, the design and external appearance of any building works, and the provision of adequate natural light in all habitable rooms. Confirm the current list against the Order, because it has been amended more than once.

Address each matter head on, in the order the Order gives them, with a short section each:

1. Transport and highways: parking provision or the lack of it, with evidence on accessibility, plus refuse and cycle storage and servicing arrangements.
2. Contamination: a desk study is normally enough for a shop unit, though a former dry cleaner, garage or petrol station needs more, and a contaminated land assessment prepared by a suitably qualified person is expected where a source is identified.
3. Flooding: the flood zone from the published map, finished floor levels and, where the unit is in Zone 2 or 3, a flood risk assessment addressing safe access and residual risk.
4. Loss of services: the honest position on whether the unit has a realistic future as a shop, with marketing evidence where it does.
5. Key shopping area: whether the authority has designated one covering the site, from the local plan proposals map.
6. Design and external appearance, where works are proposed.
7. Natural light to every habitable room, demonstrated on the plans rather than asserted.

The authority has 56 days to determine the application. If it does not, the development may proceed subject to the conditions in the Order, and the completion period runs from the prior approval date.

Natural light, space standards and amenity

Two conditions now shape the internal design of permitted development conversions and they are where small schemes come unstuck.

Every habitable room has to have adequate natural light, and the prior approval process tests it. A deep shop unit with a single frontage and a yard behind usually needs a rear opening, a rooflight or a lightwell, and a bedroom relying on borrowed light from a living room will fail.

New dwellings created under these rights also have to meet the nationally described space standard. For a single studio that means 37 m² with a shower room rather than a bathroom, which inside a 150 m² envelope rules out some of the unit splits that were once common.

Private amenity space is not on the prior approval list, so the authority cannot refuse for its absence. That does not make it irrelevant to a landlord. A ground floor flat with no outdoor space in a parade with no front garden is a difficult letting, and the yard behind is usually the asset that makes the conversion worthwhile.

Noise from neighbouring commercial uses

Shops and takeaways sit next to other shops and takeaways. The new dwelling inherits plant noise, deliveries, extraction, refuse collections and late opening.

Noise from commercial premises appears in the prior approval list for Class MA, and the lists for the two classes are not identical, so check whether it is available to the authority under Class M in the current Order. Either way, the design has to deal with it, because a dwelling that is not reasonably habitable will produce complaints, void periods and in some cases a statutory nuisance investigation against the neighbouring business.

Practical responses: glazing and acoustic ventilation specified from a measured survey rather than from a catalogue, bedrooms placed away from the party wall with the commercial unit, and no habitable room window directly beside an extract terminal. A short Noise Impact Assessment measuring the existing background and the plant rating level is worth having even where the authority cannot require one, because it tells you what glazing to buy.

Where the right does not apply

Class M falls away in several situations:

• Where the building is listed, or is or contains a scheduled monument.
• On a site of special scientific interest, in a safety hazard area or a military explosives storage area.
• Where the floor space changing use exceeds 150 m², cumulatively.
• Where the building was not in a qualifying use at the relevant date or when last in use.
• Where an Article 4 direction has withdrawn the right, which many authorities have done across district and local centres to protect retail frontages.

Check for an Article 4 direction first, before any other work. It takes ten minutes on the authority's website and it is the thing that most often kills these schemes.

What to submit is modest: the prior approval application form and fee, a site location plan, existing and proposed floor plans and elevations, evidence of the previous use with dates, a short statement dealing with each prior approval matter, and the technical notes on contamination and flooding. Where the authority is likely to argue the loss of a shop, a Planning Statement setting out the marketing history and the vacancy position carries more weight than correspondence.

Illustrative example: a vacant 118 m² hot food takeaway in a suburban parade, outside any Article 4 area and not in a key shopping area. Prior approval is sought for conversion to two one bedroom flats at 51 m² and 54 m², with the shopfront replaced by a brick and timber frontage, two rooflights over the rear bedroom and the extraction duct removed. The transport note relies on a bus route 80 m away and provides two cycle spaces and a bin store in the yard. Contamination is addressed by a desk study because of the former fryer oil storage.

This is general guidance, not legal advice. Check 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. To see which supporting documents a prior approval application usually needs, enter the site postcode on PlanScope.