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The Default Measurement Approach
The Default Measurement Approach

Key principles behind the measurement standard based on RICS IPMS 3C Residential

Elza Kreslina avatar
Written by Elza Kreslina
Updated over a month ago

The Default measurement standard is based on the RICS IPMS 3C Residential standard, developed by the Royal Institution of Chartered Surveyors (RICS). IPMS 3C specifically refers to the internal floor area of a residential unit. It includes the area within the perimeter walls at each floor level.


Measurement Basis

Measurement start

Measurements are taken from the finished surface of the wall. Areas are measured room-by-room.

Area exclusions

  1. External and internal walls, as well as walls shared with adjacent occupiers (half walls are included)

    Area exclusions: External & internal walls

  2. Columns, chimney breasts, voids in floor, upper levels of lift shafts (lift shafts included only on level they start at)

    Area exclusions: Columns

    Area exclusions: Chimney breasts

    Area exclusions: Voids in floor

    Area exclusions: Upper levels of lift shafts

  3. Unusable areas where the dimension between opposite faces is less than 0.25m (e.g., between column and wall behind it)

Area inclusions

  1. Reduced headroom areas: Areas where ceiling height is below 1.5m are included in the total area and also stated separately.

    Area inclusions: Reduced headroom areas

  2. Non-residential interior areas: areas that are still usable parts of the property, such as garages, sheds, attics, etc. - are included in the total area.

    Area inclusions: Non-residential interior areas

  3. Exterior areas: balconies, terraces, rooftop terraces are excluded from the total area, and also stated separately

    Area inclusions: Exterior areas

  4. Stairs: Area occupied by stairs is only included on the level they start at

Area inclusions: On the level they start at

Window, door and other niches and openings

  • Interior walls: If they are part of the interior walls - always excluded

  • Exterior walls: If part of exterior walls, then inclusion is based on the internal dominant face rule (IDF)

  • IDF: if element height is more than 50% of the wall height, it is included

    Area exclusions: Element height is less than 50% of the wall height

Area inclusions: Element height is more than 50% of the wall height


The Default measurement approach is focused on excluding certain structural elements, not rooms based on their usage. Both interior and exterior areas that are usable, but not habitable, such as balconies, garages, attics, etc., are still included in the total area, their area is just indicated separately. The most particular rule within this approach is the IDF rule, which applies only to niches in external walls as internal walls are excluded in their entirety. This standard is quite broad both in terms of rules and usage, but still more particular than the International standard, which is the simplest one we offer.

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