Gee, I just blabbed to my husband that a couple of people were waiting for answer about backing and maybe would like to know thickness so that their husbands could get going in project and now I have to go up to him and quote your post to him to make an exception of you... Whoops, had to check whether it was you for Timber treasures. And yesterday I got you mixed up while tree mailing w/Lynn about a hypertufa that had cool semps planted that was posted by Tabby and not you. You do hypertufa too or what?