Hey all, My hearth walls will be quite small - in a corner of 3' x 5'.. yes - basically two sheets of hardie board (1/2") in a corner. I want to use natural blue stone form my land... I will ask the wife to pick some nice pieces from our land (we have a lot of quite thin pieces laying around in the forest). Questions - 1. do I need a scratch coat? 2. mortar or thinset? and can you recommend a brand/type? 3. trowel type? 4. do I wet the surface a bit before stick the stone on? 5. some online videos show masons just taking a stone, putting some mortar/thinset on it directly, and sticking it on the wall while others show how they first lay a coat with a trowel on the wall and then attach the stone to it.... which one should I go with? Thank you so much! I promise photos!