Dwelling type

According to Approved Document L1A of the Building Regulations, the term 'dwelling type' refers to:

...the particular group allocated to each dwelling on a development to provide the basis for assessing the pressure testing regime. The allocation of each dwelling to a dwelling type should be the responsibility of the person carrying out the pressure testing. To be classed as of the same type, dwellings should:

• Be of the same generic form (i.e. detached, semi-detached, end terrace, mid-terrace, ground floor flat (including ground-floor maisonette), mid-floor flat, top-floor flat (including top-floor maisonette).
• Include the same number of storeys.
• Have the same design air permeability.
• Have similar adjacency to unheated spaces such as stairwells, integral garages etc.
• Have the same principal construction details.
• Have a similar (i.e. +1) number of significant penetrations, i.e. for windows, doors, flues/chimneys, Supply/exhaust terminals, waste water pipes.
• Have envelope areas that do not differ by more than 10 per cent.

NB The 2015 edition of Approved document M, Volume 1: Dwellings, introduced three different types of dwelling for the purposes of setting out requirements for access to and use of buildings:

• Category 1 – Visitable dwellings.
• Category 2 – Accessible and adaptable dwellings.
• Category 3 – Wheelchair user dwellings.

See: Types of dwelling in approved document m for more information.

The English Housing Survey, Energy efficiency, 2018-19, Published by the Ministry of Housing, Communities & Local Government in July 2020 suggests:

Dwellings are classified, on the basis of the surveyor’s inspection, into the following categories:

• Small terraced house: a house with a total floor area of less than 70m2 forming part of a block where at least one house is attached to two or more other houses. The total floor area is measured using the original EHS definition of useable floor area, used in EHS reports up to and including the 2012 reports. That definition tends to yield a smaller floor area compared with the definition that is aligned with the Nationally Described Space Standard and used on the EHS since 2013. As a result of the difference between the two definitions, some small terraced houses are reported in the 2014 Housing Supply Report as having more than 70m².
• Medium/large terraced house: a house with a total floor area of 70m2 or more forming part of a block where at least one house is attached to two or more other houses. The total floor area is measured using the original EHS definition of useable floor area which tends to yield a small floor area compared with the definition used on the EHS since 2013.
• End terraced house: a house attached to one other house only in a block where at least one house is attached to two or more other houses.
• Mid terraced house: a house attached to two other houses in a block.
• Semi-detached house: a house that is attached to just one other in a block of two.
• Detached house: a house where none of the habitable structure is joined to another building (other than garages, outhouses etc.).
• Bungalow: a house with all of the habitable accommodation on one floor. This excludes chalet bungalows and bungalows with habitable loft conversions, which are treated as houses.
• Converted flat: a flat resulting from the conversion of a house or former non-residential building. Includes buildings converted into a flat plus commercial premises (such as corner shops).
• Purpose built flat, low rise: a flat in a purpose built block less than six storeys high. Includes cases where there is only one flat with independent access in a building which is also used for non-domestic purposes.
• Purpose built flat, high rise: a flat in a purpose built block of at least six storeys high.

[edit] Related articles on Designing Buildings Wiki

• Air permeability.
• Air permeability testing.
• Air tightness in buildings.
• Approved documents.
• Building emission rate.
• Dwelling emission rate.
• Energy performance certificates.
• Standard assessment procedure.
• Target emission rate.
• The history of non-domestic air tightness testing.
• Types of dwelling in approved document m.