The subfloor of the bathroom has radiant panels---the pex is visible and runs in grooves in cdx plywood panels that I installed.
I am planning on building a shower next, and the first thing that I want to do is build the curb.
My thought was to build a form and pour the curb from concrete. The curb will not be too large (the shower is in the corner of the bathroom) and I have a few bags of concrete sitting around. I know that some people make curbs from PT but this seems risky to me.
My question is, what do I put under the concrete curb? I need to protect the pex. Should I put roofing paper under my concrete form?
My second question is, how best is a concrete curb anchored to a plywood subfloor? If I were going to pour a curb on a concrete floor I would epoxy a few bolts into the floor before pouring a curb. This would help with anchoring. Should I did a similar thing with a concrete curb on a plywood subfloor?
So, this makes me wonder, should I screw cement board to the entire bathroom floor before I do anything? If I did this (leaving out for the moment the area inside the curb, or maybe including this area) would be curb bond to the concrete board?