Shower design issues

[Mark Mehlberger]

I have a shower design layout that I have pretty much settled on that maximizes the area in our master bath for a custom shower enclosure. While I have a fairly fixed idea as to where the shower heads should be placed, I am having some issues determining where the valves should be placed to maximize practicality, plumbing physics, and any plumbing best practices. Here is an image of the layout with the walls lettered A-D.

Ideally, the fixed shower head will be on Wall "B" and a Handheld shower will be located on Wall "C'. I would like to place a Temperature Mixing Valve, that is preset to a temperature and always on, first in the loop, with separate volume control values down the line for each of the two shower heads. Also Ideal would be the control valve for the fixed shower head be placed within reach of the door on either wall "A" or "D" to eliminate the need to reach through the shower stream to turn the head off and on.

One issue I have is that Wall "B" is an exterior wall. The exterior walls are 2x4 stud, leaving little room for plumbing. Even though I am in south Texas (San Antonio), we have had few winter freezes. So my thought on this wall would be to insulate and drywall (greenboard or cement) as normal and then create a "wet wall" furred immediately on the inside of the insulated wall.

The current shower that is being replaced is much smaller and has a single control valve and shower head on Wall "C".

Given all that, here are the 4 options I am considering (based on the image above, the walls are laid flat in the drawings below):

Option 1 assumes keeping the original hot and cold feed in place, while all other plumbing would be new. To get the control valve on the opposite wall requires a long run from the Mixer with the pipe snaking back and forth through the "wet wall":

Option 2 assumes moving the hot and cold feed to the opposite half wall. This creates two long runs for both shower heads, but places the controls in easy to reach position prior to entering the shower.

Option 3 is similar to option 2, but places the controls on the other half wall. Plumbing in this wall may be difficult to move the hot and cold feed, but would create shorter runs than option 2 and offer the best access to the plumbing from the back side, should there ever be an issue requiring wall removal.

Option 4 places all the plumbing in the "wet wall" created as mentioned above, and potentially reduces the runs on the feed to the shower heads, but is not practical if ever an issue arises and would require a thicker "Wet Wall" to accommodate the plumbing around the Mixer.

If you are still with me this far, and I haven't lost you with my crude drawings, I was hoping someone could advise me on what option they think would be best, or if you have a suggestion on any other design I may not have thought of.

Full disclosure: I am a very capable weekend warrior, and will not be offended if you think this is over my head, or I am just plain crazy. Even though I plan to do the work myself, I will be checking on code and inspections, but want to come in with the best plan up front to ensure I don't look half-cocked and raise unnecessary red flags.

Thanks for reading.

Mark

 

[Standardairconditioner]

I am a very capable weekend warrior, and will not be offended if you think this is over my head, or I am just plain crazy.

Actually your illustration and diagrams are GREAT. Your precision implies you will take care in this personal project and do things correctly.

You have no idea the amount of new DIY's that come here in here without photos or a single diagram, and then expect advice givers to envision their setup and what they want telepathetically (because Google Earth just so happens to have the "Snow White" satellite system from the Denzel Washington movie Deja Vu), which only leads to generalized non-specific advice, which only confused them more, because they never come back to follow up on the thread they started.

You may want to consider on which sides of the walls you want to get easy access to do a repair in the future. You'll be tearing down tiles and Kerdi-Board when you can't access the other side, like exterior Wall B of your diagram. The other walls you can easily cut into drywall from opposite sides, assuming you won't tile Wall A from the tub.

You may want to consider a handheld with complete exterior supply components, so it is merely fastened to Wall B, with supply coming from an adjacent wall.

I can't see any length issues with whereever you want to run pipes, which will be all zero pressure anyways that won't store any pressurized supply water. Folks with rain showerheads on tall ceilings will easily run a longer length that you have here. Having said that, you may want to consider a ceiling showerhead if avoiding Wall B really messes up your fung shui. This is a major project, and it wouldn't be any more difficult to pipe into your ceiling or attic up Wall C.

About a custom piece of irregular L-shaped glass for Wall D, you may want to consider getting rid of that wall, and use a full piece of glass, easier to maintain and clean, and would not cost any more since the shop will be cutting your L-shaped glass from that initially. Wall C is huge, plenty wide to have everything you want on it, 2 folks showering side by side like a public shower, valves, shelves, and of course easy future access from the drywall on the other side.

Keep up the good work, and if you can add to this thread with pics of your progress, it would inspire others.

 

[Sponsor]

 

[Jadnashua]

Unless you add something like a 'toe tester' (i.e., a tub spout) in there, the line going to the 'B' wall will not completely drain, and sitting in the wall, that will be a cold slug of water that could freeze. A deeper wall will help, but maybe not enough. Is there an attic? If you ran it up on the C wall with the valve there, and sloped it well, a lot of the water would drain out when done.

 

[Mark Mehlberger]

Thanks all for the quick responses. I like to overthink my designs on paper, as it slightly reduces the "what was I thinking" moments. But not by much.

Option 1 is the best solution for usability if plumbing issues were not a problem. It places the controls in the best position to be used both inside and outside the shower. I have reviewed other suggestions about angling pipes in an exterior wall to drain when turned off, but you are correct that that option 1 will always leave water somewhere in the line in Wall B.

Option 3 could be drawn to have the fixed head feed to turn up the towards the ceiling inside Wall C until it was slightly higher than the fixed head, then slightly sloped down to the shower head as it rounded the corner. This way the water should drain from the corner to the head in Wall B and any water left in the pipe would be in Wall C. Not apparent in my drawing is a small angle bench in the corner of Wall C-D. What I don't like about Option 3 is that the controls would be in your back and shoulder when trying to use the bench.

Wall C and D are also the only ones that will most likely not be tiled or exterior on the back side.

From a shower placement standpoint, having the fixed head on Wall C aims the shower towards the door, so ideally a Wall B placement will minimize water spraying directly at the door on a regular basis. Alternatively, placing the shower plumbing in the ceiling is not ideal, as the ceiling above the shower is angled, following the roof-line, and any plumbing in this space would be subjected to the same exterior issues as Wall B. Having the fixed shower valve control on Walls A or D is best for turning the shower on and not getting blasted in the face with water.

Having a full wall of Glass on Wall D was part of my original design, but the bathroom door opens into it. I've never met a door stop that didn't fail, and just trying to avoid any accidents. Plus the half wall is better for the built-in bench in the corner.

The craziest thought I had was having the control placement as depicted in Option 1, but running the plumbing for the fixed head down the Wall C, under the shower (This is the second floor, and I have a 16" Joists below the floor), Up Wall A, through the valve, back down Wall A, back under the shower, up Wall C near the corner, then, as mentioned above, sloped downward around the corner to Wall B to allow for drainage. I figured an almost 30ft plumbing run to move the water 3 ft would be a little excessive just to have ideal control placement and minimal pipe in Wall B.

Again, thanks all for the review and suggestions.

 

[Standardairconditioner]

It's not a bad idea to put a small spout somewhere there, just so you know you can always drain off stagnant water after use.

You can get some really short-depth spouts, and it's not like it'll be in the way of your shower experience.

Spouts in shower rooms are still very useful, when you want to hand rinse some clothing or full a bucket with water, use your imagination.

 

[hj]

Your "pressure balancing loops" are ALL useless and unnecessary.

 

[Jadnashua]

Keep in mind that once you close the valve, a lot of the water will be held in there like when you put your finger over the end of a straw. That's where a toe-tester can help. Gravity can only do so much.

 

[Mark Mehlberger]

Thanks again for all the feedback.

While the toe tester sounds like a practical idea, I don't think I'm a big fan of one (but I've never seen one before either), and I can't see how it might work in this situation, as it would have to have a valve to turn it on/off somewhere after the valve for the fixed head (again, assuming I want the shower valve where I want it). Therefore, its only purpose would be to drain the pipe after the shower valve is turned off, otherwise both shower head and toe tester would have to be running at same time to use toe tester as an actual spigot. Putting them on separate circuits would defeat the purpose of draining the fixed head pipe. Again, this is my take on logic gates and physics. If practical sense means moving the Fixed Head valve somewhere that makes more sense from an "inside the wall" plumbing layout, I will have to live with the possibility of getting sprayed in the face with water when turning on the shower head.

As for the pressure loops, isn't there a possibility of pressure drop off on one of the shower heads if the water is split with just a "T" from the Mixer? Especially if the run of pipes after the split vary greatly? From a design standpoint, it would seem that there is no disadvantage in adding a pressure loop, other than wasted pipe and time to sweat it. Wouldn't it better to be safe than sorry?

I understand that my designs may require pressurized water behind a valve somewhere in Wall "B". However, After reviewing some additional "as built" plumbing in my house, I realized I have two other situations where there is water in the exterior wall. The first is in this bathroom itself, where the cold supply "T"s off to the toilet, and travels about 3ft through the exterior wall. This always has pressurized water all the way to the toilet tank. The second is my kitchen sink is on this same back wall on the first floor, again always filled with pressurized water to the spigot. So having water (Pressurized or not) in the wall may not be as big of deal as I make it out to be, Especially if I plan to insulate it as mentioned above.

This will be a fairly frequently used shower, so the standing water in the pipe after a closed valve will not stand for very long. Plus, it takes a good couple minutes for hot water to reach the shower from the water heater, which should fully flush the pipe before actual use.

Sorry for rambling again. This is kind of my therapy for justifying my design, and your chance to tell me I'm crazy or wrong. I take all criticism constructively, then just ignore it.

 

[Jadnashua]

Usually you buy a tub spout with a built-in diverter...when the valve is turned off, it opens to drain things.

Most of the time, if the piping runs next to the heated space, it won't freeze. But, after 30-years, one of my neighbors had his frost free hose spout split (no hose attached) after a weekend when it got to -11F. Once you add the valve body, in a 2x4 wall, you have essentially no room for insulation behind it.