Changing what a building is used for.

Which changes need permission. And which are already free.

Reviewed August 2026

The short answer

A change of use needs permission only when it is material. Since September 2020 shops, offices, cafes, gyms and clinics have all sat in one class, so moving between them is not development at all. Uses outside the classes have no such freedom.

In practice · Russell Terrace

Twenty-two rooms, taken to eight flats

The clearest way to explain a change of use is to follow a building with no shortcut available to it.

The order of work

01Establish the lawful useWhat the building is, before what it could be.

02Test for a shortcutOutside the classes, so there was none to find.

03Design the unitsEight self-contained homes inside the existing walls.

04One full applicationThe whole change, decided in a single consent.

A large Victorian building on Russell Terrace in Leamington Spa, in use as a house in multiple occupation with twenty-two bedrooms. The proposal was to take it to eight self-contained flats: one studio, one one-bedroom, five two-bedroom and one three-bedroom.

The job

Site: A 22-bedroom house in multiple occupation on a Leamington Spa terrace
Role: Architect and agent
Consent: Warwick District Council ref W/25/0777, granted
Outcome: Eight self-contained flats, from a studio to a three-bedroom

The first thing to settle on a job like this is not the layout. It is what the building lawfully is, because that decides which door is open. A house in multiple occupation shared by more than six people falls outside every use class, so nothing about it can be changed by moving within a class, and no permitted development right reaches it. There was no shortcut to look for.

That sounds worse than it is. One application settles everything at once, rather than a prior approval settling part of it and a planning application settling the rest. What it does mean is that the whole scheme is judged on its merits, so the drawings have to answer the questions a council will actually ask: the size and outlook of each flat, refuse and cycle storage, parking, and what the change does to the street.

Eight self-contained homes came out of twenty-two rented rooms, which is fewer people in the same building and a very different proposition for the neighbours. Permission was granted.

The mix is doing more work than it looks. A building of this kind can usually be cut into more units than it should be, and the flats that come out of over-dividing are the ones that fail on daylight, on outlook or on floor area, and take the whole application down with them. Setting the mix from what the building can carry, rather than from a unit count, is the difference between one consent and a refusal followed by a resubmission.

There is a licensing regime running alongside all of this, and the two get confused constantly. A house in multiple occupation licence comes from the council's housing service under the Housing Act, and holding one says nothing about whether the planning use is lawful. Plenty of buildings hold a licence for a use that has never had planning permission, and finding that out at the point of sale is a great deal more expensive than finding it out first.

The proof

Four changes of use, four routes.

Institution to homes · granted

17 Avenue Road, Leamington

A health service building taken to eight residential flats, with two and three storey extensions to the rear and the roof rebuilt. Consented once, then consented again on a revised scheme that dropped the second-floor rear extension and added a roof terrace. A change of use and a building project in the same application.

Warwick District Council refs W/16/0077 and W/16/1064 · granted 2016

Mixed use · granted

37 Park Street, Leamington

A unit in retail, residential and workshop use taken to a mixed use as retail, cafe and workshop for group therapy and creative sessions. Mixed use is its own animal: it is not a class, so it cannot be arrived at by moving within one, and the mix that is permitted is the mix described in the application.

Warwick District Council ref W/25/1480 · granted

No building work · granted

The Stables, Little Brington

A change of use from residential to office with no physical alterations at all. Nothing was built, nothing was demolished and nothing was extended, and it still needed planning permission and still got one. It is the cleanest illustration there is that what is being permitted is the use, not the building.

West Northamptonshire Council ref 2023/7614/FULL · permitted 2023

Storage to homes · granted

High Street, Bromsgrove

Storage and distribution premises on a town centre high street taken to residential use, with four one-bedroom flats and a rear extension. A single full application carried the change of use, the new homes and the building work together, which is the ordinary shape of a town centre conversion.

Bromsgrove District Council ref 19/00482/FUL · permitted 2020

Every planning application we make in our own name is a matter of public record on a council register, and ours reach more than 100 planning authorities across the UK.

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The first step

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01 · Where you stand

Check whether this is development at all

A great many changes that feel significant to an owner are not development, and need nothing. It is worth establishing that before anyone pays for an application, because the commonest mistake on this subject is not making a change without permission. It is applying for one that was never needed.

Planning law only catches a change of use that is material. Everything else is invisible to it. And the Use Classes Order then takes a large slice of what remains and declares it not development either, because moving from one use to another inside the same class is expressly outside the definition.

Since September 2020 that slice has been very large indeed. Shops, restaurants and cafes, financial and professional services, gyms and indoor sport, clinics and health services, nurseries and day centres, offices, research and development, and light industry that would not trouble a residential street all sit in a single class together. A shop that becomes a cafe, an office that becomes a clinic, a gym that becomes a nursery: none of it is development, and none of it needs an application.

Two qualifications matter before anyone relies on that. The first is that the freedom applies to the use and not to the building: knocking a hole in the front, putting in an extract flue or changing the shopfront may all be development in their own right, and a sign almost certainly needs its own consent. The second is that an Article 4 direction can withdraw a right in a defined area, and plenty of authorities have made them over town centres, so the national position is the start of the enquiry rather than the end of it.

The other thing worth ruling out early is whether the use you think you have is the use you actually have. A building's lawful use is what it was last lawfully used for, not what the deeds say, not what the business rates record says and not what the previous owner told the agent. Where there is any doubt, that question gets settled first, because every route on this page starts from the answer to it.

02 · The routes

Four ways a use can change

Four routes cover almost every case, and they get harder in this order. Most schemes only need to reach the second.

Route 01

Inside the same class

Movement between uses in one class is not development, so there is nothing to apply for and nothing to pay. Since the classes were consolidated in September 2020 this covers most of a high street and most of a business park, which makes it far and away the commonest answer.

Where it fails: an Article 4 direction has withdrawn the freedom over the whole town centre.

Route 02

Permitted development

Where a change is development, a national right may still allow it subject to prior approval on named matters only. The commercial-to-residential right is the one that moves the most floorspace, and both of the conditions that used to catch schemes were removed in March 2024.

Where it fails: the qualifying use has not run for the full two years before the application.

Route 03

A full application

Where the change is material and no right reaches it, one planning application settles the whole thing on its merits. It is slower and it is judged more widely, but it also carries the building work, the parking and the layout in the same consent rather than in three.

Where it fails: the use is acceptable in principle and the scheme around it was never designed to be judged.

Route 04

Proving what you already have

Where a use has been running openly for long enough, or where the change was never material in the first place, a certificate of lawfulness settles it. It is not a permission. It is a formal determination that none was ever needed, and it is the thing a buyer or a lender will ask to see.

Where it fails: the evidence is recollection rather than record, and the burden of proof sits with the applicant.

03 · The test

What a council is actually deciding

Where an application is needed, the question in front of the case officer is narrower than most applicants expect. It is not whether the new use is a good idea, or a better use of the building, or what the street would prefer. It is whether the change is material, and then what its effects are.

There is no statutory definition of a material change of use and there never has been. The government's own guidance puts it as a matter of fact and degree, turning on the significance of the change and its impact on the use of the land and buildings. In practice that means officers look at what actually alters on the ground: traffic and parking, hours, noise, smell, deliveries, the number of people coming and going, and what the change does to the character of the area around it.

Two technical points decide more cases than the policy does. The first is the planning unit, which is the piece of land the assessment is made on. Change the unit, by splitting a building into two tenancies for instance, and you can create a material change without altering a single activity. The second is ancillary use. A use that genuinely serves a main use is part of it and needs nothing, but the moment it grows into a use in its own right it becomes a change, and that line moves gradually rather than on a date.

The ancillary point is where most enforcement on this subject actually starts. A cafe that begins selling more hot food to take away than to eat in, a workshop that quietly turns into a trade counter, a farm building storing a haulage fleet: none of them changed on any particular day, and all of them ended up as a different use from the one that was permitted. Where a business expects to grow in that direction, it is far cheaper to describe the intended mix accurately at the application stage than to defend the drift afterwards.

It is also worth knowing what a permission for a change of use does not do. It does not remove the conditions on earlier permissions affecting the site, which continue to bind unless they are formally varied. It does not resolve a restrictive covenant, a lease term or a licence, none of which planning has any view about. And it does not extend to the parts of the building outside the application, so a consent for the ground floor settles nothing about the flats above it.

Common questions

Change of use, answered

What is Class E?

Class E is the single use class that since September 2020 has covered shops, offices, cafes, gyms, clinics, nurseries and light industry.

It was created by the Town and Country Planning (Use Classes) (Amendment) (England) Regulations 2020, which came into force on 1 September 2020 and swept away the old A1, A2, A3, B1, D1 and D2 classes. The class is lettered internally: E(a) retail, E(b) food and drink consumed mostly on the premises, E(c) financial, professional and other commercial services, E(d) indoor sport and fitness, E(e) medical and health services, E(f) a creche, day nursery or day centre, and E(g) offices, research and development, and light industry that could sit in a residential area without detriment to amenity. Because all of that is one class, moving between any of it is not development, and needs no planning permission at all.

Which uses are sui generis?

The ones Parliament decided fit no class: pubs and drinking establishments, hot food takeaways, cinemas, concert halls, bingo halls, dance halls and live music venues, among others.

Sui generis simply means of its own kind. The list sits in article 3(6) of the Use Classes Order and also takes in theatres, amusement arcades, launderettes, petrol filling stations, scrapyards, vehicle hire and sale, taxi businesses, night clubs, casinos, betting offices and hostels. The 2020 amendment added the pub, takeaway, cinema, concert hall, bingo hall, dance hall and live music entries. A house in multiple occupation shared by more than six people is sui generis as well, but for a different reason worth understanding: it is not on that list at all, it simply falls outside every class there is. The consequence is the same either way. A sui generis use has no class to move within and no permitted development shortcut into or out of it, so every change is a full planning application, decided on its merits.

Can an office become flats without a full application?

Often yes. Class MA is a permitted development right that takes a Class E use to dwellinghouses through prior approval rather than a planning application.

It is not automatic and it is not quick. The building must have been in a Class E use for at least two continuous years before the prior approval application. Two conditions that used to catch schemes were removed on 5 March 2024: there is now no upper limit on floorspace and no requirement that the building has been vacant for three months. What remains is a prior approval on named matters, including transport, contamination, flooding, noise, the provision of adequate natural light, and fire safety. The right is not available on a listed building or in its curtilage, on a scheduled monument, in a National Park, a National Landscape, the Broads or a World Heritage Site, or on a site of special scientific interest. In a conservation area the impact of the change on the character of the area is itself a prior approval matter. An Article 4 direction can remove the right altogether, and many town centres now have one.

Do I need permission to run a business from home?

Not if the house is still, in substance, a house. Permission is needed only where the business use becomes a material change of use.

There is no list and no threshold, because the test is whether the character of the use has materially changed, judged as a matter of fact and degree. A study with a laptop and a filing cabinet plainly has not changed anything. What tends to tip it is what the neighbours see and hear rather than what the accounts say: staff arriving, customers calling, deliveries, vans parked overnight, signage, machinery, storage in the garden, or a room given over so completely to the business that it could not readily go back. Where a use has run openly for long enough it can become lawful in its own right, and a certificate of lawfulness is the way to prove it. If in doubt, most councils will give an informal view for nothing before anyone commits.

Is a house in multiple occupation a change of use?

It depends on the number of occupants and on whether the council has made an Article 4 direction.

A dwellinghouse is Class C3. A small house in multiple occupation, shared by between three and six unrelated people, is Class C4, and nationally there is a permitted development right that allows a C3 to become a C4 without an application. More than six occupants and the property falls out of the classes altogether and becomes sui generis, which always needs planning permission. That national right is Class L of Part 3 of the permitted development order, and it runs both ways. The complication is local: many authorities have made Article 4 directions withdrawing the C3 to C4 right across whole wards, usually where student housing has concentrated, and in those areas even a three-person share needs permission. Licensing under the Housing Act is a separate regime again, and having a licence does not make the use lawful in planning terms.

Can a change of use be made lawful afterwards?

Sometimes, by applying for permission retrospectively, or by proving the use has gone on long enough to be immune from enforcement.

The immunity period in England changed on 25 April 2024. Under section 171B of the Town and Country Planning Act 1990, as amended by the Levelling-up and Regeneration Act 2023, enforcement action must now be taken within ten years for every kind of breach, including building operations and a change of use to a single dwellinghouse, both of which previously had a four-year period. Anything already immune before that date stayed immune. Where a use is immune, a certificate of lawfulness of existing use or development under section 191 puts it beyond argument, and the burden of proof sits with the applicant. Retrospective permission is the other route, and it is a normal application decided on normal grounds, not a penalty.

Does a change of use need building regulations approval too?

Frequently, yes, and it is a separate approval from a separate part of the council with its own timetable.

The building regulations have their own definition of a material change of use, and it catches most of what planning catches and some of what it does not, including creating a dwelling, creating a room for residential purposes, and changing a building into a hotel, an institution or a public building. Where it applies, parts of the building have to be brought up to current standards, and the ones that bite hardest on a conversion are fire safety and means of escape, sound insulation between dwellings, ventilation and energy performance. It is entirely possible to hold a planning permission for a change of use and find the building cannot economically meet the regulations, which is why the two get tested together rather than one after the other.

Written by

Rickett Architects

A RIBA Chartered practice, working since 1970, with more than 2,500 projects behind it. Our senior architects take projects from first survey through planning to completion, for private clients, developers and landowners across the Midlands and well beyond it.