Building depth Print

Design Outcome

Desi​gn Checklist​

  1. The building provides a reasonable level of daylight, natural ventilation and solar access for apartment occupants 
  2. The building's depth is appropriate for the intended apartment type
  3. Minimise earthworks on sloping sites through building depth and orientation
The depth of an apartment building can significantly determine the ability to daylight and ventilate apartments naturally.  
Building depth refers to the dimension measured from the front to the back of a building's floorpate  (as opposed to frontage width).

Apartment depth refers to the dimension taken from the glazing line / external wall, to the inner-most parallel wall. 

Apartment building depth is generaly determined by; 
  • ​​the preferred choice of apartment typology,  see Apartment Types for more detailed guidance on choosing the best apartment type for your site 
  • the site planning in relation to the site's size, geometry, orientation and topography.  See Site Design​ for further guidance

Better Design Practice

Consider the site's topography when choosing an apartment building typology 
Certain sites conditions are better suited to specific apartment building typologies, providing a more efficient site layout accomodating potentially more valuable apartment units. 
  • On​ steeply sloping sites, a shallow floorplate running parallel to contours should be considered, as this will minimise cut and fill, and enable shallower apartments with better daylighting and ventilation. 

Select the building typology to avoid deep apartment depths
Single aspect apartments should have a depth no greater than 8m to ensure adequate ventilation and daylighting of the apartments back wall. 

An enhanced ceiling height greater than 2.4m may enable adequate daylighting and ventilation for greater apartment depths.    ​

Dual aspect apartments  benefit from the opportunity for cross-ventilation through the apartment, increasing the maximum apartment/building depth up to 14 metres, beyond which both become difficult to achieve. 

Developments with a building depth greater than 18 metres should be able to demonstrate how satisfactory internal daylighting and natural ventilation will be achieved.
​A building or apartment depth of greater than 14 metres is likely to require artificial lighting in the centre of the building during daytime use, and is also difficult to naturally ventilate. Whilst such buildings could be artificially lit and ventilated, there are significant benefits to natural daylighting and ventilation around both the occupant's health and wellbeing, and the buidling's operational costs and maintenace. 

Consider atriums to bring light and air into deeper building plans.

Carefully designed atriums that have considered all of the associated issues can form a positive part of the development.

The optimum depth of an apartment building should be established in conjunction with determining whether the site, and therefore the building, are best suited to single or double-aspect apartments, and with the particular design and layout of the apartments.

Rules of Thumb

Limit the depth of single aspect apartments to eight metres from the glazing line

The back of a kitchen should be no more than eight metres from a window

Make double-aspect apartments over 15 metres deep at least four metres wide to avoid deep, narrow apartment layouts

North facing spaces should be designed with a layout and material finishes that support passive solar design using floor and wall areas to store heat

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