First time poster, but I've been reading the forum like mad for several days I'm planning on getting the Englander/Summer's Heat 13-NC. The installation manual says that it requires an R value of '2'. I calculate that, using cement board alone, I would need stack eight 1/2" sheets to achieve that R rating. Assuming I need to put thinset between each layer and I need to wait 24-hours for the thinset to cure before putting on the next layer, this will take up to 8 calendar days Is there anyway to build it faster? Can I skip letting the thinset cure between layers? - or can I skip the thinset between all but the top/bottom layers? PS: as a side question, do people like the 13-NC around here? Thanks!