Waterproofing across South Australia

Waterproofing is the membrane system that sits between the substrate and the tiles in any wet area. In a bathroom that means the shower floor and walls, the floor around the bath, and the junctions where floor meets wall. On a balcony or alfresco it means a membrane rated for external exposure and movement. The membrane is applied in liquid or sheet form over a primed, sound substrate, with bond breakers at every internal corner and flanges or collars at every drain and penetration.

Good waterproofing is measured, not guessed. AS 3740 sets out where the membrane must go and how far it must extend up shower walls, across floors and at junctions, hobs and doorways. The membrane goes on in at least two coats to the thickness the manufacturer specifies, each coat cured before the next. Internal corners, hobs and thresholds get a bond breaker so the membrane can move without tearing. Nothing gets tiled until the membrane has cured and been checked.

Most waterproofing failures start with the substrate, not the membrane. Flexing timber floors, unsealed sheet joints, dusty concrete and damp screed all stop a membrane from bonding. We check moisture and movement first, then patch, prime and seal so the membrane has something solid to grip. Falls are formed in the screed so water runs to the drain instead of sitting under the tiles. Much of Adelaide sits on reactive clay that moves with the seasons, so the membrane and bond breakers are chosen to handle that movement.