Waterproofing Membrane Made To Last
Let me show you a correctly done waterproofing inside a shower cubicle. That’s something I’d call bullet-proof…
Here we go again, a bit of whining Jake… Just because something looks like a waterproofing membrane, doesn’t mean it actually is. If you paid someone to install tiles in your bathroom, you should really educate yourself to a point that you actually know what you’re looking at. And look you should!
Liquid waterproofing membrane is ALWAYS applied in at least 2 coats. Drying time between applications can be 4 hours or a full day, depending on a product. You should have a long hard look at the ‘in between’ stage. What you are looking for are reinforcement tapes in the corners (wall/wall, wall/floor, floor/drain). They have to adhere to shower surface like a good wallpaper, no bubbles, no breaks between tapes, no holes. It’s all perfectly visible under a single coat of waterproofing. After a second coat the reinforcement tapes should be barely visible. This tells you a lot about the actual thickness of a coat.
But wait there is more!!! And that is the best part. Just because you have some fancy paint on a wall does not mean it is waterproof. I have seen time and time again a complete negligence to provide a proper transition between plumbing system and waterproofing membrane.
If a waterproofing membrane does not overlap a drain pipe in a shower base, it is not really waterproofing at all…
In the video above, you may notice a sticking out blue-ish matt on the step into the shower. It is a special waterproofing mat to make shower base absolutely impenetrable to water. Installation of this mat is a first step in shower waterproofing before installation of wall linings (gib, hardiflex). The mat overlaps walls by at least 150mm. Gib-board or hardiflex is installed on top of it. Using nails to fix the lower parts of wall lining sheets should be avoided and glue should be used instead (No More Nails or similar).
The rubber mat is glued to the sub-flooring without making any opening for the shower drain pipe. A metal plate (part of the drain assembly) is screwed on top of the mat first. Than we cut the opening for the shower waste. No, not a round hole. We just make a cross-cut and fold the edges of the mat inside a waste pipe. Those folds will be held in place by the rest of the shower waste assembly.
This way we make absolutely sure that not a drop of water can wander around instead of ending up in the drain pipe.
On the video you are looking at ‘a paranoid level’ waterproofing. A send/cement base that forms proper slopes is installed on top of the waterproofing mat. To avoid accumulation of water inside the slab, the liquid waterproofing membrane used on the walls is continued through the whole shower area forming a proper tank.
And that concludes our story of how proper waterproofing is done.