That looks nice! What a big difference that makes!
Was it hard to do? I have an exposed concrete wall going down the stairs into my basement that I wanted to use stone vernier on. Wasn't sure if I needed to put anything over the concrete before the cement and stone. It would be a flat wall and the only cuts id need to make would be the angles found down at the bottom by the stairs.
It was pretty labor-intensive and a little frustrating. There's definitely an art to it, and I feel like it's one of those things, like finishing drywall, that a pro would have knocked out in a fraction of the time with better results. I did get better at it as I went - which means, I'll probably never use those skills again! It did give me an excuse to get a new tool: a grinder which, with a masonry wheel, cut through the stones like butter. Making the cuts was not hard at all, but was incredibly dusty, so I did it outside. The other thing was that, in the product shot for the dry stack ledgestone, the stones are perfectly fit together. In real life, some have rounded edges or are tapered, so I'm going to have to go back with a mortar bag and fill in some voids so you can't see the brick. It's a nice product with lots of variations in texture and color, but sometimes that variation in shape didn't make for tight fits.
From what I read in the ASTM guidelines, there are a two things you have to consider with the wall surface: porosity and roughness (rougher is better). My brick fireplace had never been sealed or painted, so it was a great surface, and I didn't need a scratch coat. I did have to keep a squirt bottle handy to keep the bricks and stones wet so they didn't suck all of the moisture out of the mortar. Here's a link
to the guidelines, which I found pretty difficult to follow.