Installing new bathroom in Loft?

Hey, I know it's kind of bad manners to return own thread to top with no-content post, but I would really appreciate if anyone with experience on this provides info. It may be useful for others, too.

CALL A PLUMBER. Apparently none of the rest of us have any idea; when you find out, let US know. It would seem that the fact that the new bath would go above the old is a very good indicator but the plumber should know. Good luck.

I inherited a bath installed in a loft, on top of the existing bath, exactly as you are contemplating. I don't know how they did it and don't know the cost (previous owner's renovation 10 yrs ago). But I have to say it is not working very well. The lower tub sometimes backs up when the upper stall shower is used. So definitely get a plumber who has done this kind of work before and talk to people who are now living with the work he did. You get what you pay for!

i would guess that you will have to gut the first floor to get to the drains for the toilet and the bath. then run them up. just remember, if you flush either toilet, a person on either floor will feel the heat.

[I don't really know what I'm talking about, but I think] the most critical aspect (overlooked by amateurs) is a drain vent plan, so drains flow freely. It's a precise science.

In the plumbing chase behind the existing bathroom you'll see the hot and cold water risers, the soil stack, and the vent pipe. Or rather, take down the drywall in the loft for about the width of the bath below, and that's what you'll see.

What the plumber will do is figure out how to connect the new fixtures with those existing stacks and risers. Really doesn't involve the existing bath at all. Note that the loft floor framing will need some depth to it to accommodate the shower and toilet drains. That's why you sometimes see raised-floor baths in lofts: nowhere to put the horizontal drains without punching through into the floor below.

Forgot to mention exhaust. If existing bath has no window, you'll see exhaust ducts in the chase upstairs. You'll need to tie into the one for the bath below, unless code requires a separate duct for the new bath.

Hey, thanks a lot everybody for the answers. This is as preliminary as it can get, because I'm not even certain if I'm interested in the property. I wanted to factor in the extra bath cost. So, does anybody have any numbers to throw around, even if they're extremely ballpark? Does it alter the cost or the ease of the job if both baths are in the same floor instead of one on top of the other?

I think we need a little more info. as NWT pointws out "In the plumbing chase behind the existing bathroom you'll see the hot and cold water risers, the soil stack, and the vent pipe. Or rather, take down the drywall in the loft for about the width of the bath below, and that's what you'll see."

but is the what you will SEE? if all of those are situated inside a wall at the back of a bathroom, how are you going to get to them? Unless ALL of those items are "exposed" (and I'm not so sure your theory about them tending to be exposed in "lofts" is true, because if it's a condo, 99% it's a newly developed building, which while it happens to be in a former industrial building, gets built out (typically) the same exact way other apartments do.

Hi 30 yrs., yeah, maybe it was way too preliminary to bring this to the forum. I haven't seen the apt. in person yet, only a few pics, and in the excerpt from NWT's post that you quote, well, I don't know what plumbing chase, water risers or soil stack are. I mean, I know what "wall" is, so I guess I need to get educated before I can digest the answers to my own question. Sorry.