Wet Areas

Poor wet area design or installation can compromise safety, comfort and convenience for building users, and lead to significant structural damage.

Minimising noise and odours

Wet areas should be designed to minimise noise and odours.

On this page:

  • Noise
  • Odours


People generally prefer not to be heard – and not to hear others – carrying out ablutions. Location and layout are the main factors in reducing noise from bathrooms and toilets.

Measures to reduce noise transfer:

  • Locate WC pans on outside walls wherever possible.
  • Don’t locate sanitary fixtures on the wall between a bathroom and habitable room such as bedroom.
  • Don’t locate a WC pan on an upper floor where it is directly above a habitable room.
  • Don’t locate pipes or services close to bedrooms and living rooms.
  • Install tightly fitting doors.
  • Install sound-rated insulation in the walls or floor of wet areas adjacent to or above habitable rooms.

Another type of wet area noise is water hammer (or pressure surge). This generally occurs in a high pressure system, typically with metal pipes, when the flow of water is suddenly stopped. A sudden fluctuation in flow velocity sets up shockwaves through the pipework, causing the pipe to vibrate and make a hammering sound. Certain types of taps and valves in appliances such as washing machines may cause water hammer.

To reduce the risk:

  • specify that pipes be clipped with rubber insulated clips or be clipped over the pipe insulation
  • specify relief bends or flexible sections of pipe to absorb shock
  • specify grommets or cushioned packers where pipes pass through structural members
  • consider getting a licensed plumber to install a water hammer arrestor on the pipe upstream from appliances such as dishwashers or washing machines. These devices use a piston and air pressure to absorb the surge in pressure.


Odours in wet areas may be generated by:

  • damp towels (bathrooms)
  • surfaces that remain wet
  • water loss in traps that admit odours from drains
  • cooking smells (kitchens).

The most effective way to avoid odours is with adequate ventilation to:

  • remove cooking smells and excess moisture from the air by specifying a rangehood over the cooktop and an extract fan in the bathroom, both vented to the outside.
  • dry out surfaces to eliminate the conditions for mould growth.


Updated: 07 February 2022