Weather-tightness and ventilation Print

Design Outcome

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Design Checklist

  1. The facade of the parking structure balances the requirement for ventilation and weather-tightness
  2. The drainage of water ingress (entry of water or moisture) is managed effectively
  3. The parking structure provides clean, breathable air through passive or mechanical ventilation


​Screening a parking structure from the weather whilst providing adequate ventilation is an important functional balancing act.

While it isn’t necessary to make parking facilities as weather-tight as a habitable structure, it’s important that a suitable plan is in place to remove water when it enters the building envelope. 

Designing for weather-tightness can save significant sums of money in retrofits or repairs.

Due to exhaust fumes, ventilation is an important consideration in the design of enclosed parking structures. Ventilation can be achieved passively via natural air flow, or where this is not possible, through mechanical ventilation.

Failing to achieve a healthy and hospitable internal environment will deter patrons from using the parking facilities in the future.​

Better Design Practice

Control the flow of water​​​
  • Slope floor slabs as flat floor slabs will invariably create puddles - a minimum fall should be created through sloped floor slabs.
  • Consider also where to fall the floors to - sloping them to the outside of the building will be safer than collecting water inside the building.
  • Be mindful of the potential for water to stain facade elements and direct water accordingly.
  • Consider the provision and location of gutters and down pipes. Clever design can incorporate these as features or discretely hide them away.
  • Ensure drip edges are provided to control where water drips off a floor slab (similar to an external window sill). If not controlled, rivulets of water will track back inside the building, along the ceiling and risk dripping onto (and potentially staining) the vehicles below.

Ensure parking buildings are adequately ventilated
  • Passive ventilation is more cost effective than mechanical ventilation, but will require the certification of a mechanical engineer to ensure that enough openings are provided to achieve natural ventilation. As a rule of thumb at least 50% of a parking envelope must be open to achieve passive natural ventilation.
  • Mechanical ventilation will be required if passive ventilation cannot be achieved i.e. the parking area is too enclosed.
  • Mechanical ventilation will require horizontal space for supply and extraction ducts or blower units along ceilings, or vertical space though the building levels above if a ‘chimney’- like venting solution is necessary.
  • A mechanical engineer will need to be engaged to provide advice and design solution options to suit each individual project.​

Rules of Thumb

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