Waterproofing Internal Wet Areas

About this course.

Internal wet areas fail because water finds and exploits any weakness in the barrier meant to contain it, and it matters because a failed wet area does slow, hidden and expensive damage to the building and can harm the health of the people using it. Waterproofing is the system of membranes and details that keeps the water used in a bathroom, ensuite or laundry within the wet area — on the tiles, into the floor waste and out through the plumbing — rather than soaking into the floor, walls and structure around it. When that system works, nothing is visible and nothing goes wrong for decades; when it fails, the consequences are among the most common and costly defects seen in Australian homes and buildings.

The reason wet areas are so vulnerable is that they are wet, repeatedly and for years. A shower delivers a large volume of water directly onto floors and walls every day; baths, basins, laundry tubs and washing machines add more; and steam and condensation wet surfaces that are never directly splashed. Tiles and grout are often assumed to be the waterproof barrier, but they are not: grout in particular is porous and water passes through it and through the smallest cracks and gaps. The real barrier is the waterproofing membrane behind and beneath the tiles. If that membrane is missing, incomplete, poorly detailed or damaged, water gets past the tiles, reaches the substrate and the structure, and the damage begins.