The undulating face of the spa overhangs the pool 6-10 inches. At this angle, the pool cover track is visible about 6 inches above the waterline.

Photo 1 – The leading edge of the pool cover can be seen at the right. The spillways allow water to circulate from the spa to the pool.
Working on a swimming pool is a nice break from floors, walls, and countertops-especially if it is in your own back yard. The idea behind this pool was to showcase the hand-crafted tiles designed and manufactured by my wife at her studio works. I love to make things, and as a former machinist and millwright, this pool would be a challenge incorporating all the features we wanted. Installing the remote computer control system for the pool and spa and the underwater lighting (the computer also runs the backyard lighting and irrigation systems), designing the overhanging serpentine coping (which hides the concealed pool-cover track), and figuring out how to conceal all the works are all subjects that could fill a book; this article, though, will focus on the tiles that cover the coping and line the pool.

Photo 2 – Plaster is applied to the concrete tank. The two schools of fish in the foreground, and the rays and other fish below the scaffold, have yet to be plastered.
Porcelain ceramic tiles absorb virtually no water, and thus are the ideal choice of tiles for use around a pool environment. Ceramic tiles can be attached to practically any stable surface. They are usually found on concrete pools, but they can also be spotted on fiberglass pools, too. This pool and spa are made of concrete shot against a steel reinforcing framework: other pools are made by erecting forms for reinforced concrete. Either way, it is important to wait 28 days for the concrete to cure and strengthen before tiling can begin-especially when the tank is 11 feet deep.

Photo 3 – The spa tank gets a rough coat of plaster. The waterline tiles have been covered with tape.
All-tile pools-especially those finished with glass mosaics-are not uncommon, but they require a tank surface that meets tiling specifications: flat and smooth to within 1/4-inch in 10-feet. We did not want our pool to be flat, but instead, to undulate and curve everywhere possible. We also did not want tile everywhere, but wanted the tiles to be surrounded by plaster. If we installed the tiles on the concrete tank prior to plastering, the tiles would be bonded to the concrete, and the surfaces of the tiles and plaster would be flush.

Photo 4 – Quarter-round gripping tiles have already been installed on the edge of the coping. Sheets of mosaic tiles are staged on the right. A few stones still need to be installed.
Tiles in a submerged environment require longer curing times when regular installation materials are used. To speed construction, we used a rapid-setting thinset mortar to install the tiles lining the tank so that plastering could begin almost immediately. After each tile was positioned on the concrete tank, its outline was penciled in and the outlined area given a thin coat of hard-trowelled thinset. Each 1/2-inch thick tile was back-buttered and pressed into place. To keep tiles on the vertical areas from slipping, concrete nails were pounded an eighth of an inch into the tank and used as temporary props. The important issue here is to adjust the amount of thinset to eliminate any air pockets behind the tiles. To ensure that none of the 500 creatures installed on the tank got lost under a sea of plaster, we took photos of the pool interior after all the tiles were installed.

Photo 5 – The author uses a rubber grout trowel to press a sheet of mosaic tiles into the coping. Notice the movement joint between the tiled coping and the stone pool deck.
In addition to the sea creatures, we also installed a 10-inch border centered over the waterline of the pool. The waterline area is important because mineral crusts caused by evaporation typically occur at the waterline: tiles chosen for this area need to be strong enough to withstand frequent brushing and the usual pool chemicals. The waterline tile border was grouted before the plaster was applied.

Photo 6 – Cleaning plaster off one of the tiles. The tiles and finish coat of plaster are about 1/2-inch thick.
The spa's five spillways had to be partially tiled before plastering. The finished shape of the face, top, and spillways of the spa was achieved by bonding a layer of latex-modified setting bed mortar to the concrete. To ensure an even flow of water, a laser was used to level a screed guide made to shape the spillways. Photo 3 shows plaster being applied to the inside of the spa near the spa's waterline tiles, which have been taped over.

Pool coping can be simple to extravagant and everything in between. We wanted the coping to have a squiggly shape and overhang the pool slightly, and we needed it to support and conceal the cover track. To do this, I built a plywood form and cast a contoured coping with a stainless-steel reinforced latex mortar bed. Just prior to placing and finishing the mortar, I spread a layer of latex thinset mortar over the top of the tank to bond the concrete tank and the coping together.

Photo 7 – Along with the color of the sea, water brings motion and life to the creatures.
Although the process of placing fish one-at-a-time was a bit tedious, the coping tiles were pre-mounted into 1-by-2-foot sheets that went down quickly. Photo 4 shows the top of the pool tank with sheets of mosaic tiles staged to the right. The edge tiles were installed first, and allowed to setup hard (a rapid-setting thinset was used), after which the mosaic sheets were installed. The rolled grip edge is a safety feature that requires a strong, solid attachment. In Photo 5, I am using a soft rubber grout trowel to press a sheet of tiles into the curved surface of the coping, using latex thinset mortar. Another important element in this photo is the movement joint slot that appears as a dark line between the coping tiles and the stone deck.

Photo 8 – The 10-by-12-foot spa will seat four comfortably. Controls are under the starfish installed on the spa deck (the coral-colored spot at far left).
This movement joint is vital to the performance and longevity of pool, and it requires special fillers not normally used on residential tile installations (two-component urethanes). From the waterline up, all the tiles were grouted with a latex grout. After the grout had cured, the coping tiles were sealed with an impregnator.

The tiles set over the concrete tank are finished with damp-cured plaster-a process that requires tile adhesives that can be submerged. Depending on the thinset mortar used, curing may take up to 28 days. Photo 6 shows soft plaster being cleaned off a tile. After cleaning with a damp sponge, a trowel was used to tighten and smooth the surface of the plaster. To cure the plaster properly, the pool was filled with water immediately after the trowelling was done.

Getting all the details right took a lot of time and energy but the last grout-cleaning task was a pleasure. It involved using a utility knife and a white scrubbing pad to remove the last traces of grout from the waterline tiles. With a cold beer within an arm's reach up on the coping, and my legs dangling from the noodle keeping me afloat in front of my work, I can't think of any other tile work that was as enjoyable.