[Shop-talk] a(nother) plumbing question

[scott.hall at comcast.net]

we're re-doing a bathroom in our new house.  the shower requires a supply line larger than the existing supply.  the existing supply lines run through the slab.  I do not want to chisel up the slab to run new lines.

so, can I run supply lines through the attic?

how big should I make them?  the hot water line needs to be 1" minimum per the shower manufacturer's instructions.  this line will also feed a hydronic towel warmer and another bathroom is a few feet away from this one.  I was thinking of running a 2"+ line for future needs.

the hot water line will need a return to the heater (see hydronic heater, above).  I've seen a setup like this in magazines, so I think it can be done.  just wondering if I need to consider anything when planning.

what should I use for lines?  in lowes I saw (plain white) pvc line.  they also have "cpvc" line that was gray.  I thought the white pvc line was technically "chlorinated pvc" and just the "c" was dropped.  they're different?  also thought about black iron or copper.  cost really isn't that much of a consideration as making sure I can set it up once and not worry about it later.  I've worked with everything but black iron before, but if it's the best, I can use it.

I'd like to insulate the lines.  lowes had the foam sleeves for 3/4" line--are they made larger?  do they work?  I'd originally thought about encasing the lines in spray foam.

lastly--the water pressure is abysmally low.  the plumber said to learn to live with it, it's on a well and the tank is too far from the house.  seriously, you can't bathe in one bathroom because there's not enough water coming out.  I'm willing to install pumps on individual lines to each bathroom, or one whole-house pump, but we've got to get some pressure.  seems like I'd like to install individual pumps just before the bathroom fixtures, but I really have no idea.  the plumber didn't even want to discuss it and I'm not even sure where to begin searching.  anybody ever done this?

I'm heading to a plumbing-supply store here if I can make it, but there's not one where I live.  I was hoping to sound more informed before I go in there.

thanks in advance.