planning supply pipes for new bath...

I'm running some new copper supply pipes up to my attic for a new bathroom. Because of the odd layout of fixtures and the fact that one of the walls is going to support a new dormer, I was thinking of running most of the supply pipes in the floor.

I'd just drill some 1" holes in the joists, according to code requirements. I think it would be the easiest way to get the pipes where they need to go.

Except I worry that if there's a leak or something down the road, the pipes are all concealed under a lot of flooring. There'll be subfloor and then tile on top.

Is it a better idea to put supply pipes in the walls for easier access in case repairs are needed? Or if my system tests okay, should I assume it's okay in the floor?

Thanks.

I don't know how cold it is where you are, but in most climates, pipes in the floor system would be preferred over the attic and the exterior walls.

Most plumbers use a 1-3/8" drill bit, that way you can fit up to 1" pipe.

To keep the pipes from rattling, there are plastic pipe inserts that fit around the pipe, and inside the holes.

A small water hole in a floor joist is a lot less structure missing that in the walls.
There must be at least 2" of wood on the top and bottom of the joists.
The holes should be in the middle section to prevent damage to the joists.

As a service and repair plumber it doesn't matter to me if the pipes are in the wall or ceiling...both are better than being in a slab.

If you're in a location where pipes may freeze, you might not want to put the pipes in the wall.