New plumbing for bathroom in outbuilding on slab
I am about ready to tackle the plumbing part of a remodel to an existing outbuilding in my backyard and would like to get some advice about the layout that would work best with my constraints and make the plumbing job easier.
Let me describe this building first, and then give my constraints.
I recently moved to this house, and just gutted the outbuilding.
Located in my backyard, it is about 16'x20', toward the back of my lot.
It has electrical, but no plumbing, and is just one big rectangle now (no walls).
This building is on a slab and has a flat roof.
I also have a swimming pool in my backyard, so the main reason to add a bathroom is for swimmers to use. This is where I need help.
I arbitrarily drew the floorplan (attached) but am not convinced this is the best solution.
Constraints for this project:
- There is a home made beam spanning the 20' length that holds up the roof joists, shown in pic as dotted lines. This is made from 2 boards, each 2x10's, so it is 4x10 across the entire room, no supporting columns. I would like to incorporate the bathroom wall to support this beam, as it's span is too long and it is already beginning to sag.
- I have water that I can tap off of, this currently goes to a faucet and my swimming pool fill line. (shown in pic)
- I need to use a sewage ejector pump, I cannot gravity feed to my sewer due to grade
- I can only place my sewage basin on the right side of building, no where else will work
- Floor is all concrete and needs to be cut
- Since bathroom is not used often, and I have limited space, I thought a gas tankless hot water heater is best
- There is a natural gas pipe (steel) that goes around the back and side of the building (goes from swimming pool/spa heater to a barbecue hookup)
- I plan to put solar water panels on the roof for the pool, so i would like to limit vents to the perimeter if possible
- I would also like to add a wet bar sink (not shown in pic)
- There are existing windows and doors (shown) that I do not want to move
- size of bathroom is about 6'x8'6"
- Locations is in N. Cal (San Jose). So I think it is OK to put wet wall on outside wall?
- I plan to use PEX
- I plan to make a custom tile shower, using Kerdi or other waterpoof method
- Not shown, but am considering adding another drain in the middle of the bathroom, as I expect a lot of water due to swimmers using bathroom
I am attaching pics of the proposed layout and another one showing dimensions.
If this were new construction, then of course anything goes. But, as a remodel, I accept I have to work with what I have, and don't want to spend time or money in re-building.
Please give me any feedback or ideas, much appreciated.
I would like to finalize the design before I start any work, so could use some expert advice.