Building: an enclosed, fixed and independent space, completely or partially roofed, intended for residence or economic activity, provided the floor area of the roofed space is not less than 4 square metres.

Completed building: a building whose construction is finished at the reported period and is ready to use.

Construction  costs:  either    estimated   at    the beginning of construction work or upon completion of the  work, includes costs of  the design, supervision, construction permits, construction materials, tools, workers' wages, architect  fees,  central  heating system,  lighting, water, sewage  system,  etc.  Construction   costs excludes value of the land.

Construction activities: all activities related to different stages of construction of a building including digging of foundation, foundation work, footing beam, erection of the skeleton, brick works, installations, tile lining, sealing coat, painting, wiring, etc. Moreover, major and minor repairs in existing buildings including addition of another storey or new part, alteration or repair of installations, repair of water and gas pipes and sewage system, roof patching and insulating, repainting, changing of wall paper, repair of the compound, etc. are considered construction activities.

Construction of new buildings: activities of different stages of construction such as digging of foundation, foundation work and footing beam, erecting the skeleton, etc., for the first time.

Investment: payments made for the establishment of a building during a specified period, even if the building has not been completed during that period.

Land area:  area of   the   land   on    which the building is constructed or reconstructed

Major repairs:  all types  of construction activities carried  out   in existing   buildings    to increase   their   efficiency   and   life,   such    as increasing the  number of floors in housing units, rooms or floor area,  changing  electrical  wiring and water plumbing, reconstructing the yard  and the  compound,   major  repairs  or   changing  of main parts of water and sewage systems  or other installations  of   the   building,  repainting,   roof recovering, etc.

Minor repairs: all types of repairs which do not have the specifications of major repairs such as roof patching, slight repairing of water and sewage systems or other installations, etc.

Mixed-use buildings (both residential and non-residential): buildings used for both residence and economic activities, such as buildings with lower floor(s) for shops and upper floors for residential use.

Other construction activities: all other activities not falling under any one of the above-mentioned categories, such as preparation of land.

Reconstruction: activities of different stages of construction on a piece of land on which there had been a building pulled down in order to construct a new one.

Room: a separate space in a residential unit with a minimum floor area of 4 sq m and a minimum height of 2 m. Kitchens, bathrooms, animal sheds, and barns should not be counted as rooms. Kitchens with above specifications, however, have been considered as rooms in the 1375 National Census of Population and Housing. The 1385 Census definition of "room" included hall, kitchen, storeroom, etc., with the above specifications.

Tenure type of owned building: if the only building and its installations are owned by the occupant, but the land belongs to other person, the type of tenure is called "owned building".

Tenure type of owned land and building: if the land and building is owned by the occupant, the type of tenure is called "owned land and building".

Total floor area: total area of all floors including basement, ground floor, semi-floor, first floor, and other floors.