ABWA

Bath layout and positioning:

17. Baths and Preformed Shower bases preferable to leaking showers:

Shower baths enable a good waterproof seal and provide the best waterproofing solution. If in doubt regarding the waterproofing of a tiled shower recess then a shower bath or shower base can be installed with confidence. The destruction of confidence in tiled shower recesses can be blamed on painted acrylic and polyurethane membranes when applied to unsuitable substrates (detailed previously). The importance of a good waterproof membrane beneath shower tile beds cannot be over emphasised.

Baths or shower bases should be prepared for installation by coating with a trowel and using cement based tile adhesive over the entire underside of the bath. It is then placed / set down on a firm mortar bed of 3 parts sand to 1 part cement. This gives support along the entire length of the bath. The tile adhesive eliminates the separation of the bath from the cement bed( drumminess), giving a solid, strong platform especially for acrylic / fibreglass baths.
Previously, baths lay on bricks or on a concrete plinth up to 150mm high, without tile adhesive resulting in a lower profile.
This method was first detailed in the "The Bathroom Book", 1994. It is now adopted by bath manufacturers Australia-wide.