Single person shower to double person shower

[LLigetfa]

Yes, box it in within the attic space so that there is no insulation between the ceiling and the pipe and heap the insulation on top of the box.

[jadnashua]

As long as the pipe is run close to the ceiling and there's a bunch of insulation on top (and, there's no major air leaks), the pipe shouldn't freeze as long as the heat in the house stays on. Plus, if you slope it slightly, the run to the shower head doesn't need to have standing water in it, if sloped to the head, it will (eventually) drain out and then there's no water in there to freeze in the first place. If you put in a 'toe tester' (essentially a tub spout) the riser pipe would drain, and you can purge the cold out before you step into the shower.

[hj]

The first thing you have to understand about insulation is that it does NOT prevent ANYTHING. All it does is slow down the transfer of heat from one surface to another. IF left alone long enough then one surface, namely your pipe, will reach ambient temperature, and if that is below freezing the pipe WILL freeze, regadless of how much insulation is around it, and at that point the insulation may contain the coldness so the pipe takes longer to thaw out..

[johnfrwhipple]

I don't know about Southern Girls (actually I do) but I can tell you up North we like to stay warm in the shower. My wife takes forever to rinse her hair and I get stuck in the cold. Adding a second shower head would be great.

We plan on two shower heads when we do our en-suite shower...