As discussed in the last tiling post, we're using a slate stacked stone to provide texture on the retaining walls and to give a nice dark contrast against the ivory travertine deck and coping. The texture of the stacked stone will also provide great shadows for the on wall lighting.
The tiles themselves are basically thin pieces of slate glued together into a shape something like this:
The edges are offset to avoid obvious vertical lines when they are laid side by side. In principle the tiles should be simple to lay. In practice, whether due to the fact that the tiles are made from individual pieces of natural stone or whether due to them being the cheapest budget tiles we could find, getting them to line up well was anything but. The height variation in each tile (as well as each end of a single tile) was up to 5mm.
The height variation also made any decision regarding cutting the first course moot. I'd initially given some thought to trying to place the first course such that the final, top course would finish in at the correct height for the coping, but there was zero chance of that given the undulating edges.
The same adhesive used for the 12mm travertine tiles was used on the retaining walls, with the addition of some black concrete pigment .
So much tile cutting
If you've read prior articles, you may recall that:
The original plan called for placing the skimmer on the deck side of the pool, simplifying the pipework and avoiding any interference with the retaining walls on the other sides. This also would have simplified the bond beam concreting for the skimmer, with the ground providing natural formwork... ...Unfortunately due to a mix up with the manufacturer, the hole for the skimmer was placed in the middle of the deep end wall, which is around 1.5 metres above ground level. It also means the pipe to the skimmer will need to pass through the retaining wall. Skimmer installation post.
This means that we now have a protruding skimmer (which we encased in concrete when we poured the bond beam).
So in addition to the pool corners, a door frame at the end of the lower wall, and a side wall that steps up gradually, we have a skimmer, which protrudes out the side of the wall, requiring tile cuts for an additional two outer corners and two inner corners.
Having a box hovering above the ground with a pipe protruding beneath would also look ridiculous, so it was necessary to extend the surfaces down to the ground level.
Using cement sheeting mounted on a treated wooden frame, which was in turn mounted onto the wall and footing, we created a substrate that could accept the slate tiles.
Completing the edges
At 150mm high, the top edge of the tiles was unlikely to line up perfectly with the top of the wall. In most locations, we ended up about 20mm too high, after accounting for the expected thickness of adhesive for the coping tiles. I'd considered using the tile saw to cut the tiles to the correct height prior to placing the final course, but concluded it would take too long. Just the lower wall and side walls alone are around 17 meters. Each tile is 600mm long, so that's 28 tiles for just those walls.
So the tiles were mounted first, and I used an angle grinder to slice off the excess. This was an extremely messy endeavor, resulting in a pool full of stone dust and small pieces of slate. Preparing the coping substrate was likely to place even more material in the pool, so we held off cleaning.
After the retaining walls, the pool coping tiles are next.