Changing between class C3 and class C4 without an application

A c3 to c4 permitted change works in both directions. Class L of Part 3 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 allows a dwellinghouse in use class C3 to become a small house in multiple occupation in class C4, and allows a C4 property to revert to C3, with no application and no prior approval. The right disappears where an Article 4 direction has withdrawn it, and it never covered a house shared by more than six residents.

That last point is the one that costs landlords money. Seven sharers is not a large C4. It is a sui generis use that needs planning permission whatever the local position on Article 4.

What the class permits, and in which direction

Class L is a two-way right. A C3 dwelling can become a C4 small HMO, and a C4 small HMO can become a C3 dwelling, without an application.

The use classes themselves come from the Town and Country Planning (Use Classes) Order 1987 as amended:

• C3 covers a dwellinghouse occupied by a single person or by a family, and also small groups of up to six people living together as a single household, including some care arrangements.
• C4 covers a house in multiple occupation occupied by between three and six unrelated individuals who share basic amenities such as a kitchen or bathroom.
• A house shared by seven or more unrelated individuals falls outside both and is sui generis.

The practical dividing line is household rather than headcount alone. Three lodgers with separate tenancies sharing a kitchen is a C4 use. Three friends on a single joint tenancy who arrived together and shop together can be a single household within C3. Councils assess this on the facts and the tenancy structure is evidence rather than the answer.

Where the six person limit comes from

It sits in the definition of class C4 itself, which is limited to between three and six residents. Cross the line and two things change at once. The use is no longer within any class, so Class L cannot apply, and the council assesses a full application for a large HMO against its own policies on concentration, amenity and parking.

Large HMO applications are where a Parking Survey often earns its place, because parking stress evidence gathered to a recognised methodology is usually the only way to answer a highway objection on a residential street.

Counting residents is less obvious than it sounds. A live-in landlord, a couple sharing one room, and a child of a resident all affect the arithmetic, and different authorities approach them differently when assessing whether a use has tipped into sui generis. Where the number is close to the limit, get the position confirmed rather than assumed.

Article 4 areas and the loss of the right

Many authorities have made Article 4 directions withdrawing Class L, and the detail of what each direction does matters more than the fact that one exists.

Most directions in university towns and cities withdraw only the C3 to C4 direction of travel. Converting a family house into a small HMO then needs permission, while a C4 house reverting to C3 remains permitted development. A minority of directions withdraw both directions, which stops a landlord converting back without an application, so read the schedule rather than assuming.

Three checks before buying:

1. Find the direction on the council's website, open the schedule and the map, and note the exact classes withdrawn and the date the direction took effect.
2. Check whether the property is inside the mapped boundary, which frequently follows ward or postcode sector lines rather than anything visible on the ground.
3. Establish the property's lawful use as at the date of purchase, because a house that was already in lawful C4 use before the direction took effect keeps that use.

Where permission becomes necessary only because of the direction, no application fee is payable under the fee regulations. Our longer note on Article 4 directions and the C3 to C4 right covers the policy background to those directions and the tests the current National Planning Policy Framework applies to making them.

Licensing runs on a separate track

Planning and licensing are different regimes with different thresholds, and satisfying one says nothing about the other.

A property can be lawful in planning terms and unlicensed, or licensed and unlawful in planning terms. Councils increasingly cross-check the two registers, and a licence application is a common way for a planning enforcement team to learn that a conversion happened.

Additional licensing schemes catch smaller HMOs that fall below the mandatory threshold, and they are designated by area for a fixed period. Check whether one covers the property and when it expires.

Amenity standards the council still applies

Where an application is needed, the tests are local and reasonably consistent in character:

• Concentration policies, often expressed as a percentage of HMOs within a defined radius of the property, sometimes measured by council tax records.
• Minimum room sizes and communal space provision, which may exceed the licensing minimums.
• Refuse and recycling storage, with the number of containers matched to occupancy and a store that is not the front garden.
• Cycle parking, increasingly required in lieu of car parking.
• Sound insulation between rooms and to neighbouring properties.
• Parking, assessed against local standards and any evidence of existing stress.

A short Planning Statement addressing each local policy in turn, with a room schedule and a refuse plan, is what gets these determined at delegated level rather than drawn into a committee argument about student concentration.

Proving the lawful use before conversion

The most valuable document a landlord can hold is evidence of the property's lawful use. Where a house was in C4 use before an Article 4 direction took effect, that use is lawful and continues, but somebody has to be able to show it.

Useful evidence includes tenancy agreements covering the relevant years, council tax records, utility accounts in individual names, electoral roll entries, HMO licence history, and statutory declarations from former tenants or managing agents. Assemble it while people can still be contacted, not at the point of sale.

Use can also be lost. A long period of family occupation after a period of HMO use can mean the C4 use has been abandoned, which puts the owner back to needing permission in an Article 4 area. There is no fixed period at which that happens, and it turns on the facts, including the owner's intentions and any physical alterations.

Certificates that settle the position

Two certificates under the Town and Country Planning Act 1990 do the work here.

A certificate of lawfulness of existing use or development under section 191 confirms that the current use is lawful. This is the one to apply for where the property has been an HMO for years without permission, or where the Article 4 position is arguable.

A certificate of lawfulness of proposed use or development under section 192 confirms that a proposed change would be lawful. Use it before converting in an area where you believe Class L still applies, because a certificate is binding on the authority in a way that an email from a duty officer is not.

Both applications need evidence rather than assertion, and both carry a fee. The cost is small against the risk of an enforcement notice requiring a house to be returned to single family occupation. And a certificate is an asset at sale, because it answers the question a buyer's solicitor will ask.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.