Just winging it, learning as I go. Not a concrete guy, though I am a builder. This is my second ever concrete project (sandbox for the kids was first). Used some 2 inch thick insulation foam board covered with my mortar (Quikrete Type S with some extra plastic cement tossed in and acrylic bonding liquid in the water). No scratch coat this time. Just started carving as soon as it started setting up....90+ degrees and windy...horrible conditions to try to do this. Started setting up within 20 minutes, had to do the edges the next day after the top was carved out and allowed to set overnight under plastic. No problems that I noticed except minor shrinkage cracks that I filled the next day. Next time will remember to score the foam and paint on slurry of bonding liquid and cement paste. I will be adding vertical posts left and right of the door. And yes....my wife thinks I've lost my mind.