Here is a cross section view to imagine the slope of the space - :)

I don't like the idea of a bathroom between the bedroom and the entrance, especially for a child. Something just is unsettling about this layout. Safety issues are what are coming to mind but nothing specific is presenting itself to me. Also there was a recent post about how much slope, as it relates to ceiling height over a toilet, is allowable for code.

I like option 2 best.
The "other space"--what is it going to be? Play space? den space?

My upstairs used to be 12 x 34'. In it, we had a bedroom, at one end, closet and bath at the other, stairs in the middle...

The bathroom with sink on the kneewall doesn't work well for having a usable mirror above the sink (another reason to do option 2).

To convert an attic space to habitable space, you have to insulate it. That takes away head room. Headroom that you will need in order for it to be tall enough to be considered habitable space. A bathroom can have lower ceilings than a bedroom, but even there, the only usable portions are those that are 80" or taller. By the time you add the insulation, then this space will be unusable for living space, even for a bathroom. For a bedroom, the requirements are much stricter, and the ceilings will need to be even taller and emergency escape windows will be required as well. That will all require completely re-engineering the joists to support a live load as well as increasing the ceiling height. That's a 100K project minimum. Then adding the bath will be another 30K as well.

This space is only suitable for storage.

It depends on the definition of "bonus room". It may have already been insulated, encapsulated, and built with a living load in place... (My house is a cape style home--the space was built to be a livable, small space).

Thank you for your input GreenDesigns but I am not asking for an estimate and I am not creating fictitious space. This is a pre designed bonus room over a garage with built in room in attic trusses and floor trusses and insulation and plumbing and heating and egress windows. My post is in reference to a bathroom layout. I work with the building official for our township and both of these plans are "legal" space, it is a matter of functionality that I am researching.
Hollysprings - I appreciate your feedback as well but we do not need to pop the top or add dormers. Although that would be nice, the space was designed from the outside to stay as is and we will work with the space we have.
Everyone else, I really appreciate your input and am glad to know you are sour to the walk thru bath, that really let's me know what the masses would think if we ever were to be concerned with resale!! Thank you :) The tall section in the middle is 8' and the side walls are just under 5' with sheet rock.
It is a challenging space, but I think it will actually be cozy and have lots of character! The remaining space will probably just be a small sitting area or maybe a little craft area or something for our daughter.
Thanks again!
I have been on this site learning and reading for over three years and had to re create my user profile today to post ( I have never previously posted ), and I am so turned off by the cold welcome. I appreciate those of you who were actually trying to be helpful!

If the central space is 8' high, then your diagram is out of scale and highly misleading. You show the central area being barely 7' tall, and the majority of space appears to be under the legal usable height.

I don't quite understand the dimensions of the room- it's 30 feet long, twelve feet wide, and at the center of the room the ceiling is 8 feet tall? How short are the walls where they meet the ceiling?

I don't like the idea of a walk-through bathroom either, and I like funky stuff.

If I am correct about the dimensions, in the first twelve feet, I think I would run a hallway between a 12x6 bathroom and a 12x2 closet with sliding doors. I'd make the bathroom go the whole 12 feet so that nothing had to be placed on the low side of the room, and I would put the bath entrance in the bedroom. You could put frosted glass in the bathroom door so that light came through from the bedroom window that way.

GreenDesigns - I don't understand why you a) are being so horribly critical and b) where the heck you get your information.
The door drawn in the diagram is 6'8" which is slightly taller than the 6' person and the ceiling is then approximately 1'4" taller than that. It is to scale and merely a representation.
Hosenemesis, thanks for the ideas!

Why don't you put the bathroom up by the doorway, instead of bisecting the space? Does the door have to stay in the middle, or can it move over a little? An actual scaled sketch with dimensions would really be helpful. Doing it on graph paper is really easy.

I don't know when your home was built, but codes change over time and something that was code when the home was built may no longer be acceptable under the current code. Such as the requirment for arc fault breakers for all bedroom areas. That will have to be retrofitted to this space. What other retrofits have to be done will depend on when the home was built.

No one is being "mean" to you here. You're being over sensitive. They're just pointing out some obvious flaws in your design. :) You show both a toilet and a vanity located on walls that you state are only 60" tall. That's not possible to do. Your ceiling height has to be 80" to have a usable bath here.

Please do a scale overhead drawing with a dotted line showing the internal space of the room that is 80" or taller. That is the available space to put the bathroom. Then we can look at what the optimum layout might be for the space. But it also has to include at least a 3' corridor of at least 7' high to the bedroom area. And there are other reqirements or the space to be considered a bedroom that must be met as well.

Your most restrictive fixture for placement is the shower.

Code requires a shower to have a minimum floor space of 30" square. Code also requires the ceiling height above the entire 900 sq inches of that 30" square to be a minimum of 6'8" high. So for visualization purposes, think of each of the four walls that surround that 30" square shower having to each be a minimum of 6'8" tall.

My understanding from your description is that:

-the room is 12' wide, so you have a 6' run from the side kneewall to the centerline of the room
-the kneewall height is roughly 5' tall
-the ceiling slopes up to a height of 8' tall and reaches the 8' height about 5' away from the sidewalls
-the center of the room has a 2' width where the ceiling is 8' high.

If that is correct...or at least close to correct:

If the ceiling height at your kneewall is 5', and the ceiling slopes up to 8' and hits the 8' ceiling height about 5' away from the kneewall, your ceiling does not reach a height of 6'8" until you get about 3'4" away from the kneewall.

That measn that the minimum 30" square footprint of your shower floor can not be closer than 3'4" to the 5' tall sidewalls.

For your entire shower footprint, we have to go 30", or 2'6" beyond that. So to tuck the smallest shower that you can into that space, your MINIMUM SHOWER FOOTPRINT will BEGIN 3'4" away from the kneewall and END 5'10" away from the kneewall. Essentially, the shower wall will project out at a minimum to being right on the centerline of the room.

That precludes any chance of a true centerline pathway running from the entry door at one end of the bonus room to the windows at the other.

Now there's always a chance that my mental math is off, or that I'm not understanding the true dimensions of your room. If that's the case, certainly correct me.

But I think we need to get a good grasp of that issue before we move on to anything else.

Does that make sense?

Hi all, thanks again for your continued help. Hopefully these pictures will help get a better view. I did throw the truss plan to the side (that is what I made my drawings off of the first time around) and physically crawled up into the space and measured the sidewalls and the ceiling that is 8' in the middle - and much to my surprise it was a little wider than what I was expecting. After sheet rock it would be about 38". I drew in a few bath layouts which may not work or be the most functional, but just to give you a better idea of the space and how turning certain things might change the layout. The cross section view has a box in it representing what would be the 80" height (same as a standard walk door height). I also attached the two inspiration pics I have been looking to since we first started thinking of finishing this space. Again, it is for our baby girl - as she grows she would have her own little princess suite is my thought. Any additional space I see as a small toy area and eventually a study space or a space for her and a girlfriend to do make up or read in bean bags.

As you can see, because the stairs that are already in come up right into the middle of the space, I can't really go any wider with the bathroom if I pull it forward in the room. Also, the roof trusses are at 24" on center, so we can bump out like it shows in the shower. If the vanity would end up on that shorter wall, we could also bump out to hang a taller mirror.
The house was built less than 2 years ago, so it is up to code as far as ground fault and arc faults. When we built, we had plumbing and the heat/returns brought to the space and the trusses are designed with cavities for them below the floor. We had an added electrical box with open breakers also added for this space.
The egress window is on the far end. We have a screen porch off the back of the garage (what would be behind the bathroom), so I would not be able to add any gable dormers that extend out beyond the roof for windows...they would interrupt the roof of the porch. My idea to keep the bathroom to that side of the bonus room is so that we can put some skylights in and not have them be on the front of the house.

Sorry for the added post, but I should also mention, we are not sold on the idea of the wall between the bedroom and "den". We may just choose to keep that open and as she gets older she could add a room divider for privacy. We have considered that it should be left open so that it could serve as a man cave someday or game room if it wouldn't need to be a bedroom at some point. We may keep it open more like a studio space.

Here is an additional document I had saved a while back showing some information on working in spaces similar to ours.

I understand that this is about a bathroom. But, I have to ask if you have other children? If this is your first I want to share my thoughts about children and sleeping quarters that may be new to you or have not thought of. I have several concerns about this planned space. First, children do not like to be alone. When they are older it is fine. But my personal opinion and experience is that children should not be separated from the main family sleeping area until they are older, like in middle school. For good psychological development children need to feel safe and connected to loved ones. If this bedroom is on another floor than it is not safe because they are not in close proximity of loved ones. I can not tell in this layout if other bedrooms are near by. Second, if there should be a fire and the child is on another floor there is a poor chance of rescue by you. Third, for a small child the window is a concern for me. I have a coworker whos grandchild fell to her death several years ago out of a 1-1/2 story house window while several 3 year olds were playing. They were an upper middle class family that had a beautiful and well maintained home. There was great sorrow for them. Windows, kids, and 2nd stories do not mix.

Again I realize this is a bathroom question and you can take what you will from my comment. I need to point these issues out for others when I see them. I hope this is recieved in the goodwill and safety that it is issued.

Thank you, eduring, for your kind thoughts. The safety of our child is our top priority. I assure you, if I could have all of my children sleep in bed with me to snuggle every night, I would!

First, one comment on your plan...instead of having the sink centered on the countertop, I'd slide the sink to the left for added headroom.

Secondly, you're still missing one aspect of code, and that's the minimum ceiling height for the room. A minimum of 50% of the floor space must have a ceiling height higher than 7' tall.

Your ceiling hits 7' high about 34-3/8" away from the knee wall, so you need equal amounts of floor space on either side of that 34-3/8" line.

Your options? Right now your bathroom is 5', or 60" deep. Your first option is to increase the depth of the bathroom by moving the bathroom wall further into the attic space so it's 69" away from the kneewall. Instead of being 5' deep, your bathroom will be 5'9" deep. By increasing the amount of floorspace within the bathroom that is over 7' high that will put you right on the 50% mark.

Your second option is to do the reverse of the above. Instead of increasing the amount of floorspace with a ceiling height over 7', you instead decrease the amount of floorspace with a ceiling height less than 7'.

To do that, leave the doorway wall where it is. Pad out the bathroom's kneewall about 9" into the bathroom. This will reduce your bathroom depth from 5' to 4'4". That might leave you without code-required knee space between the toilet and the wall in front of the toilet, so you might have to rotate the toilet. You might have to increase the length of the room to get adequate toilet and vanity space.

I haven't scaled out any required fixture clearances, but here's a rough idea of what my words are trying to convey. The thing is, there's just no real satisfactory solution going this route:

One note with the second option: I'd consider using a pedestal sink instead of a vanity. Although you'd lose storage, use the depth of the padded out kneewall area to the left of the sink for built-in storage

Then there is always spitting the difference. Padding out the kneewall a few inches, and moving the doorway wall out a few inches.

Actually, code requires that 50% of the "required" floor area of the room have a ceiling height of at least 7 feet. And bathrooms are an exception to this in that they only require a minimum ceiling height of 6 feet 8 inches at the center of the front clearance area for fixtures. There is no minimum space required for a bathroom, other than that you must meet the required clearances between fixtures and/or walls.

Wow, this is why I love this site! Such awesome feedback! Catbuilder, you are right - according to our building official, there were no requirements for the bathroom beyond fixture clearance codes. Thank you for the time to write to confirm that thought.
Mongoct, thank you so much as well - even if the bathroom doesn't require the floor space, there is something to be said for your thought of building out the wall - that is something I hadn't previously considered and I think I might play with that idea. The toilet is the one thing I am pretty particular about. Usually 5' is a minimum depth with the toilet/knee clearance so I would really like to stay at a minimum of 5' in front of the toilet - and that is why I do consider turning the toilet and having the vanity on the side wall. A typical vanity is 21" deep with a 22" deep countertop. I could build out the wall behind that a bit to increase the wall height for a mirror.
You have me thinking...
TY!!

Well, that 50% 7' rule doesn't apply to baths, but it DOES apply to bedrooms. So figure out the square footage deducted by the bath and other room and make sure that there is still enough square footage at the right height for the bedroom.

You folks have more leeway regarding code interpretation than I do in my locale. In my area both exceptions to R305 apply to bathrooms.

I have to honor the 7' exception (50% rule) if the room has a sloped ceiling, which this bathroom that we are discussing does.

On top of that, we have to honor the 6'8" fixture clearance for bathrooms.