Here is a shower deck made from Tiger Wood; Goncalo Alves. This was a challenging build as the shower pan used a linear drain, but in addition of the slope for the drain, there was also a ‘pan’ running it’s length making the surface below anything but flat. There was also limited height in which to support the deck material that was desired to be flush with the tile floor.
In order to achieve this, there were a few rounds of template work and scribes to the floor. I made Baltic Birch plywood supports and deck piece to prove the build theory would work, fine tuned that system to the desired spacing, and then transferred the completed templates to the final hardwood pieces.
You can see the shape of the ‘pan’ in the support pieces, they get thinner over on the wall end of the supports. There is a shallow dado on the underside of the deck pieces to hold the supports and planks in place, a 1/8” rounded over relief between boards for water drain, and a 1/8” gap all around the perimeter of the shower pan. Some 3D printed bumpers supplied by the owner around the edges should keep the deck in the desired location as well as some feet on the bottom of the planks near the wall to gap the final varying distance to the ‘pan’ curve. Wood is unfinished in the images but will probably be maintained with an oil and the open wall of the shower will get glass hung for the enclosure.