Dwelling structure (STRD)

This variable classifies the structural type of private dwellings and describes the physical form of the dwelling. It assigns each dwelling to a standard category based on its structure, such as a separate house, a semi‑detached dwelling, a flat or apartment, a caravan, or a cabin, as well as other types of structures including houseboats or improvised dwellings. 

Private dwellings 

This variable is not collected from a question on the Census form. 

This variable is initially sourced from the ABS Address Register, as outlined in the ABS Address Register Information Guide. Dwelling structure may also be updated when ABS field officers return information gathered during their visits to dwellings. 

New dwellings identified by Census staff can have their structure recorded by the field officer. Where this is not possible, dwelling structure may be imputed from the characteristics of nearby dwellings during processing. Depending on the dwelling type and how the Address Register has been updated, a private dwelling’s structure may be derived from the Address Register (supported in some cases by Building Approvals data) or from field‑collected information. For non‑private dwellings, structure is coded as ‘Not applicable’. 

Certain dwelling types, such as improvised homes, tents and sleepers‑out, receive additional attention during processing to ensure the quality of data relating to the homeless population. 

Information on the structure of private dwellings has been collected to some degree in every Census since 1911, though classification methods have changed over time. Until 1986, occupied craft in marinas were treated as non‑private dwellings; from 1986 onward, occupied houseboats and small boats have been classified as occupied private dwellings.  

From 1976 to 2011, dwelling structure was recorded by Census Field Officers in the Collector Record Book when forms were delivered. In 2016, this information was collected mainly through the new Address Register. This continues to be the primary source of dwelling location data, with updates made by Field and Office staff as needed.  

Definitions for separate houses and semi‑detached dwellings were updated in 2021. The former half‑metre separation rule was removed, and a separate house built in the last 20 years must now be structurally independent, aligning the definition with Building Approvals data.  

There have been no changes in 2026.