Class L and moving between C3 and C4 use
Class L permits a dwellinghouse to become a small house in multiple occupation and back again, with no application. The limits are the household test, the six-resident ceiling and the Article 4 directions that withdraw the right.
Class L of the General Permitted Development Order lets a dwellinghouse become a small house in multiple occupation, and lets a small HMO go back to being a single dwelling, with no application and no fee. That is the whole of the right. Class L, the C3 to C4 permitted development route, is also the right most often withdrawn: many authorities have made Article 4 directions over all or part of their area, and in those streets a full planning application comes before the first tenant moves in. Everything else in this area follows from two questions. How many households, and has the right been taken away.
What Class L permits in both directions
Class L sits in Schedule 2 Part 3 to the Town and Country Planning (General Permitted Development) (England) Order 2015. It permits a change of use from Class C4 to Class C3, and from Class C3 to Class C4. There is no prior approval stage, no notification, no fee and no condition requiring you to tell anyone.
The right is symmetrical, which landlords forget. Taking a small HMO back to single family occupation is itself a change of use, and Class L is what makes it lawful without an application. That matters when a lender or a buyer wants the property marketed as a house again.
What Class L does not do is authorise building work. Loft dormers, rear extensions, new openings, bin stores and hardstanding are assessed on their own terms. Whether Part 1 householder rights continue to apply once a house is in C4 use is argued both ways by practitioners, because article 2 of the Order defines a dwellinghouse by exclusion rather than by occupation. The cautious route is to put the question to the authority in writing, or to apply, rather than to build and hope.
The definition of a small house in multiple occupation
Class C4 in the Town and Country Planning (Use Classes) Order 1987 covers the use of a dwellinghouse by between three and six residents as a house in multiple occupation within the meaning of section 254 of the Housing Act 2004. Two limbs have to be satisfied. The number, and the section 254 test.
Section 254 asks whether the building is occupied by persons who do not form a single household, whether they share a basic amenity such as a toilet, a washbasin or cooking facilities, and whether at least one of them pays rent. A couple counts as one household. A parent and child count as one household. Five unrelated sharers are five households, so a five-bedroom let to five students is C4.
The quiet trap is Class C3 itself. C3 reaches up to six residents living together as a single household, which is why a small religious community or a group of people living as one household can sit in C3 rather than C4 at the same headcount. The dividing line is not the number of bedrooms. It is whether the occupiers form one household or several.
Article 4 directions removing the right
Article 4 of the Order lets a local planning authority withdraw permitted development rights across a defined area. Removing the C3 to C4 right is the most common householder-scale use of that power, concentrated in university towns, seaside towns with large Victorian stock and inner city wards with high HMO density.
Where a direction is in force you need a full planning application for the change of use, and you are assessed against the authority's own HMO policy. That policy is usually expressed as a concentration threshold, a proportion of HMOs within a stated radius of the application property, with supporting criteria on amenity, refuse and parking. The threshold and the radius are set locally, so read the adopted policy rather than assuming a figure.
Check two places before you commit. The article 4 direction dataset on planning.data.gov.uk gives national coverage, and the authority's own constraints map gives the boundary and the date the direction took effect. Directions are often ward-specific rather than borough-wide, and the boundary can run down the middle of a street.
A direction that removes the C3 to C4 right does not usually remove the reverse right. Read the direction itself, because the classes withdrawn are listed in it.
Six or more occupiers and the sui generis position
Seven residents takes the property outside Class C4 altogether. A large HMO has no class, so it is sui generis, and a change to sui generis use needs planning permission everywhere in England whether or not an Article 4 direction applies.
| Occupation | Use class | Route in England |
|---|---|---|
| One person or one family | C3(a) | no change of use |
| Up to six residents living as a single household | C3(b) or C3(c) | no change of use |
| Three to six residents, more than one household, sharing amenities | C4 | Class L, unless withdrawn by an Article 4 direction |
| Seven or more residents sharing | sui generis | full planning application |
The tipping point catches people mid-tenancy. A six-bed C4 house with a seventh room formed in the loft becomes a large HMO the day the seventh tenancy starts, and no amount of licensing paperwork changes that. If the business plan needs seven beds, apply for seven from the outset and put a Planning Statement in with the application that deals with concentration, amenity and parking head on.
Licensing as a separate regime
Mandatory HMO licensing applies to houses in multiple occupation let to five or more people forming two or more households, under the prescribed description made in 2018. Authorities can also designate additional licensing for smaller HMOs under section 56 of the Housing Act 2004, and selective licensing for private rented housing generally.
Licensing and planning are separate statutory regimes administered by the same council, often by officers who do not speak to each other. A licence does not make an unlawful use lawful, and a lawful C4 use does not excuse an unlicensed HMO. Both have to be right.
The mandatory licence conditions set minimum sleeping room floor areas: 6.51 m² for one person over the age of ten, 10.22 m² for two people over ten, and 4.64 m² for a child under ten. Those are licensing minimums. They are not planning standards, and a room that satisfies the licence can still be refused on amenity grounds.
Amenity standards and room sizes
Where the right has been withdrawn, the application stands or falls on the detail. Most authorities with an Article 4 direction publish an HMO or houses in multiple occupation supplementary planning document covering kitchen worktop and appliance provision per occupier, bathroom ratios, usable external amenity space, sound insulation between rooms, cycle storage and bin capacity with a sensible route to the kerb.
Parking is where applications die. In a street already at capacity the authority will want evidence rather than assertion, which usually means a Parking Survey carried out on the Lambeth methodology, with overnight counts midweek and at the weekend outside school holidays. Do the counts before you buy, not after refusal.
The Nationally Described Space Standard does not apply to HMOs, so do not cite it as a defence. Use the local amenity standard, and say in the submission which criterion each room meets.
Evidence of the lawful existing use
If you are buying a property already in HMO use, the use has to be lawful, and the burden of showing that falls on you. Collect tenancy agreements, council tax and licence history, electoral roll entries, utility accounts and, where people will give them, statutory declarations from former occupiers.
The enforcement time limits in section 171B of the Town and Country Planning Act 1990 were amended by the Levelling-up and Regeneration Act 2023 towards a single ten-year period in England. Check the current position and the commencement date before you rely on any period, because the rules that apply depend on when the use began.
A Lawful Development Certificate under section 191 of the 1990 Act is the only formal way to confirm that an existing use is lawful, and section 192 does the same job for a proposed use. The certificate costs a fee and takes weeks, and it is worth both when a sale or a refinance depends on the answer. The planning unit question can also matter here, because an annexe or a converted outbuilding let separately may not share the main house's status.
One last warning for Article 4 areas. If you let a lawful C4 house revert to single family occupation for a sustained period, the HMO use can be treated as abandoned, and you may not be able to return to it without permission. Landlords who treat the reverse right as a free option often find it has quietly closed. The same logic applies to the time-limited rights in other parts of the Order, as the Class MA vacancy and continuous use conditions show.
Enter your postcode on PlanScope to see which reports a change of use application in your area is likely to need. This is general guidance rather than legal advice, so 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.
Frequently asked questions
Do I need planning permission to turn a house into a shared house for four tenants?
Four unrelated sharers in a house is Class C4 use, and Class L of the GPDO 2015 permits the change from C3 to C4 without an application. The exception is an Article 4 direction covering the property, which withdraws the right and requires a full planning application. Check the authority's constraints map and the article 4 direction dataset before you let the rooms.
How many people can live in a C4 house in multiple occupation?
Class C4 covers between three and six residents forming more than one household and sharing a basic amenity. A seventh resident takes the property outside the class, making it sui generis, which needs planning permission in every authority. Adding a loft room to a six-bed house therefore changes the consent position even though the building looks the same.
Does an HMO licence mean the planning use is lawful?
No. Licensing under the Housing Act 2004 and planning control under the Town and Country Planning Act 1990 are separate regimes, even though the same council runs both. A licence does not authorise an unlawful use, and a lawful C4 use still needs a licence where the mandatory, additional or selective scheme applies. Deal with both.
Can I convert a small HMO back to a single family house without permission?
Class L permits the change from C4 to C3, and Article 4 directions in most areas withdraw only the C3 to C4 direction of travel. Read the direction itself to confirm. Reverting is worth thinking about carefully, because a C4 use left dormant for a long period can be treated as abandoned and may not be resumed as of right.
What evidence proves an existing HMO use is lawful?
Tenancy agreements, council tax and licence records, electoral roll entries and utility accounts covering a continuous period, supported where possible by statutory declarations. A Lawful Development Certificate under section 191 of the Town and Country Planning Act 1990 is the only formal confirmation. Enforcement time limits were amended by the Levelling-up and Regeneration Act 2023, so check which period applies to your start date.
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.