The Housing (Scotland) Act 1987 provides the legal definitions of overcrowding.
Overcrowding - legal definition
There are two legal definitions,  based on the room standard and the space standard. If either or both of them apply then a dwelling will be statutorily overcrowded. This is an offence unless the overcrowding falls within one of the exceptions.
The room standard
The room standard is based on the number and sex of people who must sleep in one room.  The room standard will be contravened in a situation where two people of the opposite sex must sleep in the same room. The exceptions to this rule are:
cohabiting or married couples who can live in the same room without causing overcrowding
children under the age of ten who are completely ignored in the calculation.
'Room' is defined as being available for 'sleeping accommodation' only if it is of a type normally used in the area as a bedroom or a living room. However the standard does not limit the number of people of the same sex who can live in the same room (but see the space standard).
The space standard
The space standard is based on the number of people who may sleep in a dwelling of a particular size.  The number of people depends on the size of the room, the number of living rooms and bedrooms in the building and the age of the occupants. There are two ways of calculating the space standard and both should be applied. The method that gives the lower figure for the number of persons entitled to occupy will be the statutory limit.
|Number of rooms||Number of people|
|5+||2 per room|
|Floor area of room (sq. feet)||Number of people|
For both the above assessments:
children under one year old are not counted
children under ten years old but not under one count as a half
rooms under 50 square feet are not included
a room is counted if it is available as sleeping accommodation.
There are four situations in which there will be no overcrowding even if the room and space standards are not met.
If the standards are breached because a child of the household has reached one of the specified ages (one year or ten years) and the household has not changed in any other way then there will be no breach of the overcrowding provisions.  The birth of a child will also not count as children under one are disregarded. In order for this exception to apply the occupier must not fail to accept an offer of alternative accommodation or secure the removal of anyone living there who is not a member of the family.
If the reason for overcrowding is that one of the people sleeping in the accommodation is there on a temporary basis (for not more than 16 days) and is a guest, then there will be no breach of the overcrowding provisions. 
If the local authority gives permission for the overcrowding then no offence will be committed. The occupier, not the landlord, must apply for the permission. It will only be granted in exceptional circumstances for a specified number of persons and for a period not exceeding 12 months. 
A local authority may pass a resolution permitting more than the allowable number of people to sleep in particular classes of houses during the holiday season(s).
It should be noted that the provisions relating to offences and the overcrowding provisions are not generally in force in Scotland. They have only been brought into force in the Dysart Ward of the Burgh of Kirkcaldy and the Burgh of Queensferry. Once in force, offences can be committed by the landlord and the occupier. The landlord will commit an offence if s/he fails to give written notice of the number of people who can lawfully sleep there (although this is not generally in force). The occupier will commit an offence if s/he causes or permits the house to become overcrowded (although this also is not generally in force).
If the occupier allows the property to become overcrowded then s/he will lose the protection of the Rent (Scotland) Act 1984 and the Housing (Scotland) Act 1988 as regards eviction.
Last updated: 7 June 2021