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Failure of waterproofing in wet areas is one of the most common building defects. Research suggests that the poor installation practices are a significant cause of waterproofing failure. Waterproofing is a major issue in bathroom renovation and costs of repairs are considerable.

The BCA outlines the minimum performance requirements that must be met in relation to wet areas. The project documentation should therefore specify that waterproofing systems are to be installed in accordance with the BCA.

A wet area is an area within a building supplied with water and includes bathrooms, showers, sanitary compartments and laundries.

Silicone sealing of all wall and floor junctions, including all internal corners, is recommended to avoid hairline cracks at these junctions. Silicone sealing can be colour matched to tile grout where necessary.

Where such regulation applies, waterproofing should be applied by licensed applicators only. Waterproofers can assist with the recommended type to be used. Considerations such as drying times and the number of coats required for each type will vary.

Plumbing and drainage means bringing water to the outlet or fixture and a means of taking the waste/soiled water away. Plumbing and drainage are required for:

• Taps and basins
• Showers
• Baths and spas
• Toilets, cisterns, bidets and bidettes
• Floor wastes

Occasionally a tank water system is gravity fed only. Plumbing fixtures that are installed on low pressure or gravity feed system should be carefully selected for that purpose. Local statutory authorities should be consulted prior to commencing plumbing work.

Bathroom is defined as a wet area and therefore specific guidelines and restrictions are regulated with respect to the electrical equipment, power points, lighting, switchboards and switches near sinks, basins, shower recesses, shower roses, hand-held showers, and baths. All electrical work must be carried out by a licensed electricians and is to be undertaken in accordance with AS3000 – Electrical installations, state and local government regulations.

Restriction Zones: The regulations of AS3000 use the term ‘restriction zones’ when referring to wet areas. These zones have a direct relationship between the location of an electrical component and the distance to a water-holding device. In essence, the closer together two are, the more stringent the regulations.

Bathroom requires a proper ventilation. There should be a proper and careful consideration during the planning stage to avoid moisture build-up, restriction to mould growth and the other problem that can have a detrimental effect on materials used in the bathroom. The steam from a hot shower can push the relative humidity from normal levels (40 percent or less) to 99 percent in less than 10 minutes. Clothes dryers are also major contributors to humidity build up.

The options needed to be considered during the planning stage to manage contaminated air from the bathroom, toilet (where it is a separate compartment), or laundry are:

• Natural ventilation: Include windows, grills (ceiling or wall), ventilating skylights and roof windows.
• Mechanical ventilation: Exhaust fans

Heating should be fixed, as portable heating could be hazardous as there is a possibility of it being used close to water sources. Heating may be:

• Radiant: A radiant heater heats the object rather than the surrounding air. Radiant heaters include heated tower rails.
• Convection: Convection heaters fill the room with warm air and work well the room which are well insulated.
• A combination of two: include hydronic radiator panels and many types of gas heater.

More popular now in new bathrooms is underfloor heating, which is another form of radiant heat. Hot water piping is embedded in a concrete slab during a new home construction.

Good lighting can change the look and feel of a bathroom. Well-designed lighting can change a mood for a spa or simply illuminate the area at the mirror to make application of cosmetic easier. When planning lighting for a bathroom, remember to consider natural lighting during daylight hours.

Lighting design combines three main functions: background or general lighting, task lighting and accent or feature lighting. General lighting provides room-wide illumination, and can be achieved with wall lights, ceiling pendants and recessed down lights. Task lighting is required for grooming, cosmetic applications, and accent lighting for decorative objects or features.

The basic light sources are:

• Natural Lights
• Incandescent
• Fluorescent
• Halogen or Dichroic
• LEDS