Do I need planning permission to convert offices to residential?

What Class MA allows

Class MA sits in Part 3 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015, usually called the GPDO. It permits "a change of use of a building and any land within its curtilage" from Class E (commercial, business and service) to Class C3 (dwellinghouses). Government planning guidance confirms that Class E takes in the old business class, "B1 including offices", along with shops, cafés, nurseries, health centres and gyms.

Permitted development is still planning permission. It's granted nationally by the GPDO rather than by your council, and it comes with limits and conditions. For Class MA, the main condition is prior approval: you can't start until the council has dealt with an application on specific matters.

Three things Class MA doesn't do:

• It covers the change of use, not building works. Government guidance says that where physical works are needed to carry out a change of use, developers need to check whether they're development and get planning permission if necessary. New windows, extra storeys or a new entrance may each need their own consent.
• It doesn't replace the Building Regulations. Converting a building into dwellings is a "material change of use" under regulation 5 of the Building Regulations 2010, so the regulations apply to the work.
• It isn't a temporary use. Once converted under Class MA, the building must stay in use as dwellinghouses (paragraph MA.2(6)).

The conditions: what has changed since 2024

Class MA came into force in 2021. It has been amended several times since, and some figures you'll still see quoted no longer apply. As the legislation stands today (legislation.gov.uk shows no outstanding changes):

• No floorspace limit. The original cap, which excluded buildings where the floor space being changed was more than 1,500 m², was removed on 5 March 2024 by the GPDO (Amendment) Order 2024 (SI 2024/141).
• No vacancy requirement. The rule that the premises had to be vacant for at least 3 continuous months before the application was removed on the same date, by the same order.
• Two years in Class E use. This one remains. Paragraph MA.1(1)(b) says the use of the building must have fallen within the listed classes "for a continuous period of at least 2 years prior to the date of the application for prior approval". Before 1 September 2020 those classes were A1, A2, A3, B1, D1(a), D1(b) and D2(e) (but not an indoor swimming pool or skating rink). From that date, it's Class E.

The right is also excluded where the building or its land is, or is part of:

• a site of special scientific interest;
• a listed building or land within its curtilage;
• a scheduled monument or land within its curtilage;
• a safety hazard area or a military explosives storage area.

It's also excluded where the building is in an area of outstanding natural beauty, the Broads, a National Park, a World Heritage Site or an area specified under section 41(3) of the Wildlife and Countryside Act 1981. If the site is occupied under an agricultural tenancy, both the landlord and the tenant must expressly consent.

Conservation areas aren't on the excluded list. Instead, a ground-floor change of use in a conservation area adds a prior approval matter, below.

Article 4 directions and planning conditions

Even where Class MA would otherwise apply, two things can switch it off for a particular building.

An Article 4 direction. Article 4 of the GPDO lets the Secretary of State or the council direct that a permitted development right doesn't apply in a specified area, or to a particular development. Government guidance is clear on what that means: an Article 4 direction "only means that a particular development cannot be carried out under permitted development and therefore needs a planning application". It's not a refusal. National policy (NPPF policy DM10, August 2026) says directions should be limited to situations where they're necessary to protect local amenity or the wellbeing of the area, based on robust evidence, and applied to the smallest area needed. Check with the council whether a direction covers the building's address before you rely on Class MA.

If prior approval has already been given before a direction comes into force, the direction doesn't stop that development, as long as it's completed within 3 years of the prior approval date (article 4(2)(a)).

A condition on an earlier planning permission. Article 3(4) says nothing in the GPDO permits development contrary to a condition on a planning permission. If the building's permission has a condition removing permitted development rights or tying it to office use, Class MA may not be available. Read the planning history before you assume it is.

The building's current use also has to be lawful: the GPDO doesn't grant permission where the existing use is unlawful (article 3(5)).

Space standards and natural light

These two tests shape the design more than any other.

Every home must meet the nationally described space standard. Article 3(9A) of the GPDO says Schedule 2 doesn't permit any new dwellinghouse with a gross internal floor area under 37 m², or that doesn't comply with the nationally described space standard (NDSS). This applies to every permitted development right that creates homes, including Class MA. Under the NDSS, a one-bedroom, one-person home with a shower room is at least 37 m² (39 m² with a bathroom), a one-bedroom, two-person flat at least 50 m², and a two-bedroom, four-person flat at least 70 m², all on one storey. The NDSS also sets minimum bedroom sizes: a single bedroom of at least 7.5 m² and a double of at least 11.5 m².

So the number of homes in an office floor isn't its area divided by a target flat size. It's what fits once each flat meets the standard and the stair, lift, corridors and stores are taken out. Our guide to how many homes you can build on your land walks through that capacity test.

Every habitable room needs adequate natural light. This is a prior approval matter (paragraph MA.2(2)(f)), and it's the one the council can't weigh against anything else. Paragraph W(2A) says the council "must refuse prior approval if adequate natural light is not provided in all the habitable rooms of the dwellinghouses". Habitable rooms are rooms used for sleeping or living, other than rooms used solely for cooking. Bathrooms, toilets, corridors, hallways, utility and laundry rooms don't count.

The GPDO doesn't define "adequate". Deep office floors are where this bites: a bedroom in the middle of a deep plan, lit only from a corridor, is unlikely to pass. Test the layout early, room by room, and talk to the council about how it will assess light.

What the council looks at: the prior approval matters

Before starting, you apply to the council for a determination of whether its prior approval is needed on these matters (paragraph MA.2(2)):

1. Transport impacts, particularly to ensure safe site access.
2. Contamination risks in relation to the building.
3. Flooding risks in relation to the building.
4. Impacts of noise from commercial premises on the intended occupiers.
5. In a conservation area, where the ground floor changes use in whole or part: the impact on the character or sustainability of the conservation area.
6. The provision of adequate natural light in all habitable rooms.
7. The impact on intended occupiers of introducing homes into an area the council considers important for general or heavy industry, waste management, or storage and distribution.
8. Where the change means losing a registered nursery or an NHS health centre: the impact on local provision of that service.
9. Where the building meets the fire risk condition: the fire safety impacts on the intended occupants.

The fire risk condition (paragraph MA.3) applies where the building will contain two or more dwellings and is 18 m or more high or has 7 or more storeys. For those buildings, the application must include a fire statement and the council must consult the Building Safety Regulator.

Government guidance describes prior approval as "a light-touch process", and says the council "cannot consider any other matters" than those set out for the class. It isn't a re-run of a planning application. The council must still have regard to the National Planning Policy Framework, so far as it's relevant to the matter being considered (paragraph W(10)(b)).

The application, the fee and the 56 days

Paragraph W sets out what the application must include. For Class MA, that means:

• a written description of the development, and a plan showing the site;
• a statement of the net increase in dwellinghouses;
• a floor plan showing the total floor space of each new home, the dimensions and proposed use of each room, and the position and dimensions of windows, doors and walls;
• elevations of the dwellinghouses;
• a site-specific flood risk assessment where the Environment Agency must be consulted, and a fire statement where the Building Safety Regulator must be consulted.

The fee. Regulation 14(1)(zc) of the planning fees regulations sets the Class MA prior approval fee per proposed dwellinghouse, and regulation 18A increases fees each 1 April in line with CPI. GOV.UK's published table for 2026 gives £260 for each proposed dwellinghouse from 1 April 2026. A ten-flat scheme pays £2,600. The fee is refunded if the council rejects the application as invalid.

The 56 days. Development can begin when the council tells you prior approval isn't required, when it gives prior approval, or on "the expiry of 56 days following the date on which the application … was received" without the council telling you whether prior approval is given or refused (paragraph W(11)). Before deciding, the council gives notice of the application, either with a site notice displayed for at least 21 days or by serving notice on adjoining owners or occupiers (paragraph W(8)).

Two practical points. If the 56 days pass without a decision, you build in line with the details in your application, so make them complete. And development must be completed within 3 years of the prior approval date (paragraph MA.2(5)).

The council can grant prior approval with conditions reasonably related to the matters it considered (paragraph W(13)). A refusal can be appealed under section 78 of the Town and Country Planning Act 1990. Development under permitted development can also be liable for the Community Infrastructure Levy where the council has a charging schedule in place.

Before you buy: a short order of checks

1. Use history. Evidence that the building has been in Class E use, or a listed older class, for 2 continuous years.
2. Location and status. Not listed, not in a National Park, AONB, World Heritage Site or another excluded area. Note whether it's in a conservation area.
3. Article 4 and conditions. The council's Article 4 directions for the address, and the conditions on past permissions.
4. A test layout. Every flat meeting the NDSS, and every habitable room with a window that can give adequate natural light.
5. The prior approval matters. Noise from neighbouring commercial uses, flood risk, contamination, access and, for taller buildings, fire safety.
6. Works outside Class MA. Any external changes that will need their own planning permission, and Building Regulations from the start.

If Class MA isn't available, a planning application is the other route, and it opens up a wider set of policies. A feasibility study tests both routes for the same building before you commit.

Frequently asked questions

Looking at a specific building?

If you're weighing up an office building, the Feasibility Sprint tests what it can hold before you commit. Our architects visit the site, review the planning route and the site's history, and test three options, each with a unit mix and area schedule checked against the NDSS and the planning risks rated issue by issue. It covers sites in England.

Book a free intro call, get the free site first look or see the Feasibility Sprint.