How high is the knee wall? You're going to have a window in that knee wall? Dormer or low-set? What is the ceiling height over there? Would a skylight work instead? Why do you prefer not to have the window over sink or shower?

I think all of your sketches tend to chop up your space. To have to pass the shower walls on your way to the sink or toilet is rather confining.

Usually it's better not to put plumbing in an exterior wall, and it's nearly always cheaper to keep it one wall.

My instinct would be to put the sink on the left wall opposite the door, as it the pleasantest part of a bathroom to see when you walk in or the door is left open.

Then the toilet next to it. A sink should have 30 inches of wall space and a toilet 32 inches - but I am not sure if that space can overlap in the unoccupied part of the wall - I think it can.

And then you are left with the space next to the exterior wall. You could have a big shower the whole width of that wall and a window set high in that wall (or a skylight). Or a smaller shower with the window next to it and shelves or vanity table or chair under the window. You can have frameless glass doors which will keep the visual space open, or even a partial partition and doorless shower - you put the showerhead in the partial partition aimed away from the shower opening. Or you could have a tub with a hand held shower.

What you do with that exterior wall depends a lot on your climate, and how high that knee wall is.

Thanks, birdgardner. I think maybe I'm being unclear since I'm not sure of my terms.... I guess it's not a knee wall, it's the wall of a dormer, so the bottom part is protected from the outdoors by the attic, which is insulated, while the upper part of the wall (where the window will be) is exterior. So I figured any plumbing on that wall would have to go into that bottom, insulated part of the wall.

We prefer no window in the shower because of moisture and maintenance issues; and not over the sink since we want a mirror there. Skylights not an option.

The layout you suggested is the one we'd originally planned on, and probably we should just go with that. I was worried it was too crowded, and that it would create an empty corridor effect in front of the door, but likely the space is too small to feel that way anyway....?

Thanks for the input!

I like your first config. But I would put the sink on the left wall (I agree with birdgardner there). And I would put a neo-angle shower.

Thanks, andydad. I do think the neo-angle shower uses the space better, but I just don't care for them. But maybe I am letting my prejudice against them interfere with what would work best.

Hearing your suggestions is very helpful.

Okay. If you have a dormer, than the appearance of the window from the outside really matters. It has to be properly centered or spaced from the other windows, and in proper proportion. So no high-set windows. Your dormer is going to dictate where that window goes, so you need to draw it into your sketches.

It looks like you've drawn it in three different places, but do you really have that much flexibility? A single window off-center in a dormer would look bad. So would multiple windows unevenly placed. Does the dormer contain only the bathroom, or extend beyond it?

Even when your wall is insulated and in an attic, it's still an outside wall. If you have freezes, better not to run pipes through it.

If you have a tub or shower under the window, you can have a curtain for moisture control and draw it back when for light when you are done with your shower.

The dormer will have three windows in the other room, and one in the bathroom, so they won't be evenly spaced, and it seems to us that having one window offset it won't matter exactly where it is. Also, it's not the side of the house that we view much.

But anyway, what you're saying would dictate that all the plumbing go on the left-hand wall, as the window wall is an exterior wall with the lower half inside the attic. We do have freezes!

So that would mean the ONLY option is the one with all the fixtures lined up along the long left wall. That's what you're saying, right?

If so, it certainly makes things simpler.... ;)

Your pipes probably would not freeze as long as your heat was working, though they might bring you cold cold water in the morning. It's if the power goes off for a few days in an ice storm that people's pipes freeze. Or they go away for two weeks and the furnace quits.

You should probably play with cut-outs on a model of your dormer and try to place the windows in some harmony as seen from the outside - for instance the one window on the bathroom side corresponding to the center window on the bedroom side. Or relating to the windows in the floor below. Something that pleases you and makes sense.

When I look at the older houses in town, their builders did pay attention to this - the newer ones, not so much. You get these off-set windows and wonder, why do it that way when it would have been just as easy the other?

And after you like where your window is from the outside, work the bathroom from the inside.

I like sketch 2, though I would probably flip the toilet and the vanity. Under the window you could put a hamper, table, or scale. The area looks wide enough to enter the shower from that side.