The main problem with having a shower with only a waterproof guarantee is that water never sleeps, and as it causes damage, it’s often a slow and silent process that happens unbeknown to the homeowner. Generally, by the time an issue is discovered, the problem is large and costly to remedy.
Damaging Effects of Water Seepage
When water manages to penetrate through the grout or tiles and leak onto the waterproofing membrane below there is no guarantee that all water will track to the waste. ‘Capillary action’ can cause any excess water to track outside the shower, even uphill, and along the bathroom floor underneath the tile. It will eventually reach the end of the waterproofing and spread. “It might be that the carpet in the hallway starts to smell damp and musty, or that the wall framing starts to absorb moisture and begins rotting – something that will happen without people realising,” Crest Showers’ Jerome Capper says.
It’s because of this risk that traditional methods of constructing tiled showers are no longer acceptable, yet still comply with the Building Code, Jerome says. “The traditional way of building tiled showers was to mortar a slope in the concrete floor and then just waterproof the walls and floors, complete the tiling and then fit shower screens to the top of the tiles. This is still a widely practiced methodology and complies with the Building Code. But it does not address the potential risk because the glazing is sealed to the surface of the tile, not the waterproofing. In these cases, while the shower might be waterproof, it is not leakproof.”
“Water leaking, or even just escaping, from a shower can remain unnoticed for long periods and cause catastrophic damage. Water can affect the substrate, and then tiles start moving which allows more water to penetrate, which compounds the problem. Properly detailed and installed waterproofing is absolutely vital behind tiled surfaces with cement-based grouts because inherently, tiling is not waterproof, and failure of tiled surfaces is a common problem in New Zealand.”