With the
bathroom wall construction completed, I now have to make major progress on the shower - with the tiler coming on Monday there's a lot of work to do in just four days...
The next step is to finish waterproofing the area under shower, and permanently affix the raised shower floor. As mentioned in previous posts, I've gone a bit
crazy with the waterproofing and have several redundant layers to minimize the chances of a leak. As part of this strategy there are actually two "floors" to the shower - the actual raised shower floor (because it is sitting on top of a steel beam), and then the sub-floor, which is level with the rest of the bathroom. Each "floor" - including the entirety of the bathroom floor - is to be fully waterproofed to increase the redundancy, (hopefully!) minimizing the chances that if there is ever a leak, it will not penetrate through to the flat below ours.
I started by waterproofing around the shower drain opening in the sub-floor - a large hole that was cut into the plywood while
leveling the bathroom floor and installing plywood around the drain.
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| Feb 16th - applying the waterproof membrane around the drain |
After the membrane was dry, the following day I fitted the Marmox insulated tile backer board, made sure everything fit together properly and prepared a bucket of flexible tile adhesive. As with the shower walls, the combination of the rubberized membrane, waterproof tile adhesive and waterproof tile backer board creates the redundant waterproof assembly.
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| Feb 17th - fitting the Marmox board in place |
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| Testing to make sure everything fits! |
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| Ready to go - mixed tile adhesive, cleaned sub-floor. |
As mentioned in our roof posts, I have a serious
aversion to mortar and troweled adhesives...mainly because I'm not that good at working with them and generally make a mess. This time I made a huge effort to learn from those initial experiences, mix smaller batches, and work quickly - yet carefully. Fortunately it went better than I expected, with minimal mess! The sub-floor was coated with the adhesive in sections, and the Marmox boards were placed over them.
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| Adhesive partially applied |
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| First Marmox board down |
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| Next few pieces on the left - the last section of adhesive on the right |
In between the board edges, silicone is applied, and then taped over with a special (and expensive) waterproof tape that completes the waterproofing system at the joints.
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| Completed Marmox board with silicone along the joints |
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| Extra waterproof tape around the drain opening |
After all joints are siliconed and taped, I added several intermediate supports for the raised shower floor, making sure everything was level and cutting openings for the boiler's white condensate line. I then did a few final reviews of the waterproofing to verify there were no gaps or neglected areas, and screwed the waterproof plywood in place.
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| Feb 18th - Additional wood supports for the plywood base |
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| Final shot before closing-up: fully taped and waterproofed |
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| The plywood based permanently fastened |
Permanently attaching the plywood made me somewhat nervous, as from this point onwards, I'll never again be able to access the drain and sub-floor in case there's a leak. I guess this is where having the redundant layers of waterproofing come into play, and provide some peace of mind. Not to mention a bit of confidence from the success of our new roof, and the fact that it has not (so far!) leaked...
