i hope someone can allow me to skip the experimental stage and tell me what type of adhesive or tile setting material i should use to hang various tiles from 4x4 - 6x6 on the solid pine stairs. They would only be set on the risers which is the part of the stairs that is verticle as you take each step up. And yes... as we step up, the front of the feet might hit the tiles.....But i am thinkig it might not be so serious as i have seen this at the local restaurant. But some of the softer tiles worry me,,,,i may just try to use the hardest tiles...

Do i use a silicon or glue gun type of adheisve or a tile adhesive that is a glue base with latex? The wood might expand and crack the tile,,,,but i have never hung tiles on wood. Do i also have to seal the wood first?

Can i simply seal the pores of the pine with only one coat of some type of urethane?

P.S.i am trying to use the most eco friendly non toxic material so i rather not use things like silicone if that is real toxic..

Sil