Planning permission may be needed to authorise the use of a residential property. Planning permission is required for building operations, e.g. building a new house, but it can also be required if there is a change of use from one particular type of residential accommodation to another. Residential use is not a single broad classification. Rather, residential use is broken down into different types. In this guide we outline the different kinds of residential use. Slightly different rules apply in England and Wales.

The different types of residential use

For planning purposes residential use in England and Wales can be categorised into the following types -

Single houses

Single houses are those occupied by a single person or by a family (there is no limit on the size of a family for these purposes). This will be a house, whether semi detached or detached, terraced or a bungalow. This use falls within Class C3.


A flat is a self contained flat and it includes flats or maisonettes on more than one floor. These are flats which are again occupied by a single person or a family (again irrespective of the size of the family). Flats and houses are treated differently for planning purposes. However, a flat which is occupied by a single person or family also falls within Class C3. Each flat in a block is treated as a separate unit for planning purposes.

Small house in multiple occupation (HMO)

A small house in multiple occupation (HMO) is a house lived in by between three and six unrelated individuals who share at least one basic amenity, i.e. kitchen, bathroom or toilet. There must be more than one household although an individual can be a single household for these purposes. The type of accommodation which falls within this category is a house occupied by a group of young professionals or students, or a small bedsit house. The definition of a small HMO is more complex than this but this gives a broad indication of what falls within this category. It is classified as Use Class C4.

Flat in multiple occupation (HMO)

This is a self contained flat which is occupied by between three and six unrelated individuals who, again, share one or more basic amenity and where there is more than one household. It also falls within Use Class C4.

Large houses in multiple occupation (HMO)

An HMO which has more than six residents will usually be treated as a use on its own (what in planning terms is called a sui generis use). It includes properties such as larger shared houses with more than six occupiers or larger houses comprising bedsitting accommodation, i.e. non self-contained units where there are more than six residents.

When is planning permission required if there is a change of use?

Even though the broad classification of use is residential, planning permission is required if a material change of use takes place. This can occur where use changes from one type of use as set out in the previous sections to another, e.g. where a single house is converted to flats or bedsit (non self contained) accommodation. The test is one of whether the change of use is material or not. This depends on all the circumstances including the resulting impact on the amenities of the adjoining area. For example, it is more likely that there will be a material change of use if there is a significant increase in noise, parking, comings and goings etc, as a result. Professional advice may well be needed on this topic because each case can turn on its own particular circumstances. For example, a house occupied by a family of four, say mother, father and two adult children, may instead be lived in by four unrelated young people. This may not be a material change of use particularly if there is no resulting impact on the neighbourhood, e.g. no increase in car usage and the group of four young people are closely linked with each other. Again, it all depends on the circumstances.

Planning permission is automatically required where a building is sub-divided into more than one self contained unit. Likewise, if a large flat were to be sub-divided into two separate flats then, again, planning permission must be obtained. Sub-divisions of this kind are automatically treated as a material change of use.

Small HMOs in England

In England, unless an Article 4 Direction is in force a change of use from Use Class C4 (a small HMO) to a single house with up to six residents (Use Class C3) is covered by permitted development rights. Where permitted development rights apply there is no need to apply for express planning permission to authorise the change of use although if any external building works are involved planning permission is needed for these. Likewise, if a flat which is treated as a single flat for planning purposes is changed over to a small flat in multiple occupation with up to six residents (Use Class C4) permitted development rights authorise this, unless an Article 4 Direction is in force. The reverse also applies where use changes in the case of a house or flat which is a small HMO to use as a single house or flat within Use Class C3. Local authorities can make Article 4 Directions taking permitted developments away in which case express planning permission has to be applied for. A number of towns and cities in England have made Article 4 Directions removing these rights either in the whole of their areas or in part of their areas so you need to check with your local planning authority.

Small HMOS in Wales

Permitted development rights are not in place for Wales at this time if the change in use is from C3 to C4. As such landlords will potentially need planning consent if they plan to change the property classification to an HMO. They should also pay the fees of £380 when changing use from C3 to C4.

Changing from C4 to C3 is covered by permitted development however and so landlords do not need to apply for permission to change the use, or pay a fee for this change. Landlords should consider this carefully before they do however as there is no guarantee they will be able to change it back to an HMO afterwards.

The C4 classification was only implemented in Wales from January 2016. Prior to that all properties with less than 7 occupiers were classed as C3. Any property currently in use as an HMO can continue to be used that way. However, if a property that has been used as an HMO is then used as a family home it may be difficult to use it as an HMO again. Going forward any further conversion of property to an HMO use is likely to be difficult.

Due to the recent nature of C4 classification in Wales, landlords should check for evidence of historic use before purchasing a property. As long as this exists it will be possible to continue HMO use. However, there should be no expectation that further family homes can be moved to HMO use and anyone considering doing so should look to obtain an outline planning permission or a Certificate of Lawful Planned Use or Development before investing substantial funds. The long-term effect is likely to be a reduction in HMO property in Wales and a limit on more properties being used in this way.

Where there is a limit of six occupiers is this the maximum?

Six is not necessarily the maximum number. This is because ultimately it turns on whether or not there is a material change of use. Increasing the number of occupants from six to seven or eight may not constitute a material change of use. If it goes to nine occupants then it almost certainly would be treated as a material change of use but this could be the case even with seven or eight occupiers. It all depends on the circumstances and especially the resulting impact on the amenities of the neighbourhood.

What are Use Classes?

In this guidance we have explained that single dwellings/flats fall within Use Class C3 in England and Wales. Small HMOs (including bedsits) are within Use Class C4. Any change of use within a Use Class does not need planning permission. For example, if use of a single dwelling/flat changes so that it is occupied by a family instead of a single person, then no planning permission is needed. Likewise, changes in numbers of occupants between three and six in Use Class C4 will not attract the need for planning permission in the case of a small HMO. Often, a change of use from one Use Class to another will require planning permission but not always. As explained above, this is only required if there is a material change of use, although this will usually be the case if you change from one Use Class to another. Alternatively, it may be covered by permitted development rights so that express planning permission is not required, as pointed out already in earlier sections in relation to England, unless an Article 4 Direction is in force.

Two unrelated occupiers

In England there is a quirk deliberately incorporated into the legislation, where a property is occupied by two unrelated individuals, e.g. two friends. This is not an HMO; nor does it fall within Use Class C3. In reality, this is not an issue because using a property in this way would not be regarded as a material change of use anyway, especially where a single dwelling/flat is occupied by two unrelated individuals. This is an area of planning law which has been little explored since the changes which took place in England in 2010. In Wales it would fall within Use Class C3 anyway so long as the two unrelated individuals are viewed as a single household.

Landlord & Investment Show
Martin Co
Property Six Pack (Gas Elec)

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