Converting shower enclosure to curbless design

[nae32123]

Hi all,

I am remodeling a second floor bathroom with a concrete subfloor and could really use some help with my shower construction. The original was a 35 x 39" pre-fab pan that I would like to replace with a larger 40 x 48" curbless design. It is a corner shower that would be open to a freestanding tub with a walk-through opening on one side and a glass splash screen on the other. (If I figure out that the opening will be too narrow when I do a mock-up, my backup plan is an outward swinging door or floor-to-ceiling sliding panel instead of the stationary one.) If it matters, I am using pebble tile for the wet flooring areas, 12 x 24 porcelain for the shower and tub walls and probably travertine or porcelain up to 18 x 18" for the main floor.

The complication I have is that the floor under the old shower is level with the rest of the bathroom and I am trying to avoid cutting out the concrete to recess it. The room is not huge, so I could raise the surrounding floor a bit to meet the height at the shower entrance. I've ruled out the traditional mortar bed because I cannot add enough height to the main floor to allow for the thickness of the 2nd layer of deck mud according to the guidelines I've seen. I have two potential solutions:

1. a thin-bed construction with a liquid or surface-applied membrane. If I understand correctly, the minimum recommended thickness at the drain is 1/8' with 1/4" slope for every linear foot. I would bring the rest of the floor to an even height with self-leveling concrete and was looking at either Hydroban or the Kerdi membrane for the waterproofing.

2. cut a trench in the concrete to relocate the drain and convert it to a linear drain just inside the glass, running all the way to the walk-through opening. Then I can slope from the back wall and edge of tub front towards the main floor and the height where they meet should be relatively easy to match up.

Is either of these a reasonable approach and which do you think has a better chance of success for a first timer? Attached are pictures of my proposed layout and the exposed area where the shower was to show the drain. My main concern is that I'm underestimating the thickness of the mud or overlooking something critical since this is my first shower. No way do I want to learn by trial and error on this project, but I'm reasonably handy and I think with some guidance, I can do it right!

Thank you for any input you might have. =)

~Linnea

[cx]

Welcome, Linnea.

I suspect that's some sort of a condo? If so, I recommend contacting the Association and your local code compliance office before you go beyond the planning stage.

I would recommend you relocate the linear drain to the north wall in your drawing. That would require a bit of a compound slope at the north side of the entry, but shouldn't be too complicated at all.

I recommend you use a minimum slope of 3/8ths" per foot because of your pebble tile shower floor.

I'd recommend you move the shower head to the north wall, near the west corner to minimize splash-out, of which you will have some.

Depending upon the drain you elect to use, I would suspect you'll need an absolute minimum of 3/4" mud thickness at the drain and perhaps more.

You may well not meet the floor deflection requirements for a natural stone floor in the rest of the room, but if you use a reinforced mud bed there with an uncoupling or crack isolation membrane over it you may be OK. You'll easily meet the minimum mud thickness of 1 1/4" for that type installation.

Have you given any consideration to how you will waterproof the glass/floor junctions?

My opinion; worth price charged.

[nae32123]

Thank you, CX! This is actually a single family home. I will look into moving the showerhead as you mentioned. For the drain, though, If I move it to the back wall, it would be so high at the front where the glass and opening is that I could not raise the main floor by enough to make it level. Based on your recommendation of 3/4" thickness at the drain, I could manage that only if the drain was at the glass. Is that a bad idea in and of itself? I haven't looked in detail into the glass installation method, but I think either just brackets/hinges with silicone to seal the joint, or a U-channel on the floor.

[Tiger Mountain Tile Inc]

Welcome Linnea!

I'm trying to figure out where the entrance to the shower would be? Is it right next to the tub? My math says that opening would only be 18" and the reality is it would probably be an inch or so smaller than that.

Or is it more straight on from the bottom to the top in your drawing?

[nae32123]

Hi Jim. Yes, it is the ~18" space next to the left end of the tub. I know it's narrower than normal. The only reason I thought it might be ok is that it is only closed in up to the tub height of 20 inches +/- and unobstructed at the top. I'm going to tape it off or use 2 x 4's to test it, and if it's no good for an average person (I'm only 5'2 and small so I have no problems), I'll have to do a door or sliding panel instead.

[Tiger Mountain Tile Inc]

If you are getting a permit I don't think that will meet the codes for your area but you can always check. As far as the drain goes I don't know of any that are that small so you'd probably have to get one that is 48 inches. Is that what you are thinking?

[nae32123]

Yes, I was thinking a 48" linear drain basically along the inside of the glass. So the floor would pitch from the back wall towards the glass. That way I could start the slope as high as possible and have it closer to meeting the height of the main floor on the other side of the glass.

[sycamorebob]

Linnea, what is the reason for a curb-less shower with a 18 inch opening? I must be missing something

[nae32123]

Hi! The only reason for the curbless is that I prefer the look of it. I wanted to have a fully enclosed "wet space" with the tub inside the shower, but the room just isn't big enough. I think having the glass sit directly on the floor keeps the space looking larger and more open. 18" is just what was left after fitting the corner tub. And if it is too tight a squeeze, I'll use a sliding panel or door to allow a wider opening. I do have an alternate design for a curb shower with full enclosure and separate tub if this plan isn't feasible after all.

[sycamorebob]

Linnea, thank you for the explanation, I would advise to have the door / opening to the shower a minimum of 24 inches.

[zeaflal]

You will see that a 2 inch height difference between drain and curb is often recommended and is required by code in many jurisdictions. One reason is to have a place to contain the water if when the drain becomes clogged. How much height your shower really needs is driven by the obliviousness (or cluelessness) of the users in addition to surface area and water flow considerations.

2 inches is not an unreasonable number for a one size fits all rule. Ignoring any code compliance issues, you can certainly get away with somewhat less. Adding a linear drain at what would be the curb location doesn’t completely contain the water but it does increase your options. Just remember that water always flows downhill and on a level surface puddles expand away from the source. Once you give serious consideration to where the water could go (especially if your floor is not truly level), you may find a curb looks more attractive.

You could also increase your opening width by placing the opening on a 45 degree angle. Would not have much effect on space utilization but certainly would change the look.

And finally it would be good if you edited your profile to include your geographic location. That gives people here a lot more knowledge about local customs and options than you might think.

[nae32123]

Thank you for the input. I am pretty sure I do want the wider 24" opening, so I will find a way to incorporate it. I am reconsidering cutting the concrete out to drop the shower. I'm worried this might be the best way to ensure adequate construction. If I forgo the curb, should I still apply the 2" rule to the height difference of entrance to drain? The linear drain would have glass on the other side, so I believe it should contain most of the water, other than some outside the open walk-through space. I've updated my profile to show that I'm in south Florida.

[zeaflal]

Originally Posted by Linnea

If I forgo the curb, should I still apply the 2" rule to the height difference of entrance to drain?

I think that is up to you (and your code compliance officer) to decide. And note it is not the "entrance to drain" but rather the highest point (the point the water must crest to escape) to drain. The highest point "could" be far outside the shower if everything was properly waterproofed. That could be an issue with some inspectors.

For comparison, my shower has a linear drain against the curb. Since it does clog on occasion, I tend to be aware of it while showering. Not uncommon for the water to be a half inch deep before I notice. Of course the shallower the water, the smaller the surface area, so that first half inch occurs pretty fast.

[Tiger Mountain Tile Inc]

You might play around with the idea of angling the corner of the tub but you may not get 24 inches out of it. It seems to me the minimum might be 20 but I don't remember.

If your project is getting inspected you'd be wise to run the drawing by the building dept before committing to anything. The 2 inch drop rule is sometimes enforced and sometimes not. It's becoming a bigger issue with the popularity of curbless showers and I've heard there's talk about modifying the rule on that.

[nae32123]

Thank you for clarifying that, Larry. My project most likely won't be inspected, but I still want to do it right

Jim, shortening the glass to leave more room is a good idea. Unfortunately, I can't angle the tub that way because it is freestanding, not a deck.

It seems like removing the concrete or adding a single threshold under the glass would simplify things. That way I can make the mud as thick as it needs to be without worrying and I'm sure I can figure out a compound slope at the entrance to make the transition.