Is it possible to lay wood planks on tile mortar and grout in between with 1/8" gaps, like you would tile. I have a concrete slab sub floor that is all above ground level. I live in North Central Arizona. We have a good rainy season during the summer, but are high and dry for most the year.
The only thing that I think could go wrong would be the boards warping and separating from the mortar beneath, or perhaps shrinking and leaving gaps in the mortar. I guess I wouldn't mind cracks or gaps; those are easily filled, but warping would be a problem. I want to use 3/4" or 1" heartwood pine boards that I can get locally. I would be able to let them sit in my garage for a few months or even a year if needed.
I want to try mortar for the look, but also for maintenance. The gaps should make replacing a board easier.