On Oct 8, 6:21*pm, wrote:
I have a retaining wall outside that I've been modifying lately, it's
about 50' long and 3' high. Currently it's constructed out of just old
pressure treated 2x12. I would like to build a faux rock wall. I think
that would look much better. My questions are, is faux rock the
correct term? Second, what do I use for backing? Can I mortar the rock
to the pressure treated wood then grout? Any good websites where I can
find more info? I Googled faux rock, but didn't come up with too much.

Is the fake rock a 100% cement-natural mixture, any plastics in it
will possibly be an issue since concrete breathes and you have
moisture comming from behind with the wood, freeze thaw issues arise.
Wood as a back is not stable and will rot, in the first winter pieces
will fail if you go below maybe 25f. Maybe on hardiboard, concrete
block as a base if its natural fake stone, im just guessing here talk
to some local pros and supliers.