To provide plenty of support for the fiberglass grating substrate, the deck joists were installed 12 inches on-center, and the stair stringers were laid out and installed so that the maximum span between them at the bottom tread was no more than 16 inches on-center.
The fiberglass grating panels can be cut to fit with a circular saw. Here, the deck surface fits just beneath the door threshold, with the framing sloped slightly away from the house for drainage.
Cellular PVC trim was used to form the curved fascia trimming the stair risers. A heat gun was needed to warm up the trim and make it flexible enough to bend around the tight curves. When heating and bending PVC lumber, keep the gun moving to avoid blistering the trim.
The author planned the framing and the tile layout so there would be full tiles, rather than small cut pieces, along any edge. Anywhere that tiles needed to be cut, no piece was narrower than 4 inches.
To ensure good adhesion, each slate tile was washed off with water, thoroughly dried with compressed air, and wiped down with denatured alcohol before glue application and installation.
The tiles were glued to the fiberglass grating with a structural adhesive, which was applied to the back of the tile with a caulk gun and then spread with a V-notch trowel.
At the edges of the deck and the steps, the tiles needed to be scribed, then cut to fit with a wet saw.
The tiles were butted closely together and installed without grout, allowing water to drain between the tiles and through the fiberglass grating.