## understanding shower curb height

Posted by bbstx (My Page) on
Wed, Nov 6, 13 at 23:28

 I did not want a curbless shower, however, I want the least curb practical. I was talking to the construction superintendent today about the curb. 6 inches is standard. The super says he could go as low as 4 inches. I would like 2 inches. The super kept talking about the "shower pan" and the rubber lining and how if the drain stopped up, the shower could hold 4" of water with no trouble. Could someone please explain all of this to me (including how there is going to get to be 4" of water in the shower and I'm not going to realize the drain is stopped up and turn off the water)? Please use simple words, preferably not exceeding 2 syllables.

Follow-Up Postings:

### RE: understanding shower curb height

 Don't know about where you live, but here (in CA) our new shower curb is 3" above the bathroom floor on the outside, and where we step in thru the door into the floor inside the shower is just 2" down from the top of the curb. We have a linear drain 3' away from that opening. So very easy to step over compared to our old 6" curb shower that had a center drain. Our shower is 4'x3', with the shower floor just 3x3. If you had a long shower with a linear drain at one short end, you might be able to have a 2" or less curb where you step in! We are also restricted to shower valves that allow 2.5 gpm, so I would have to fall asleep in the shower before a clogged drain would overflow even this slight curb. Sometimes these regulations do need some 'splain'n. -Babka

### RE: understanding shower curb height

 Thanks, babka. I'm curious: how does a linear drain make any difference over a regular circular drain? The construction supervisor has never mentioned code or regulations. I think it is just his personal preference of stamping out one more same ol' same ol' rather than having to think about getting it right if something is different. Right now we are at the framing stage. There is a circular drain about the center of where the shower will be. Can that be converted to a linear drain easily? DH is going to have his knee replaced next summer. That is not a "maybe." It is a "for sure." When he had the other knee done last year, we did not have a walk in shower in our house. All were shower/tub combinations. We had to use a transfer chair to get him in the tub. I want to make sure we have as few limitations as possible. Currently we have no mobility problems, other than his knee bothering him. I'm trying to plan this house for "ageing in place." So, the more obstacles I can eliminate now, the fewer issues I will have to address when/if we do have mobility problems.

### RE: understanding shower curb height

 Try Googling "ADA shower pan". I know there are some options that may or may not work for you. But there is some information out there.

### RE: understanding shower curb height

 bbstx: Curbs are obsolete. Go curb-less. You won't regret it.

### RE: understanding shower curb height

 treb, unfortunately, I'm behind that curve. The slab has been poured and curbless would require lots of jack-hammering and re-doing. Not impossible, but I have other places I want to put my money.

### RE: understanding shower curb height

 I'm watching this thread carefully. I'm pretty sure we're too late to make changes but I'm curious to read the replies. They're building our shower floor next week.

### RE: understanding shower curb height

 our linear drain has a round hole in the middle. It looks like the whole thing is a drain, but just the middle where the water goes. So it drains like any other drain, but instead of having a centered drain with all four corners of the shower sloping to the drain, a linear drain allows you to slope the shower floor in one direction. The water collects in the linear trough and is funned toward the center of the drain, which is a standard size drain hole. It may be possible to install a linear before the contractors mud the floor, likely depends on current slope of your shower floor. Sounds like they already framed it with slope set, and the drain is roughed in? I would discuss with your contractor but if you don't want to spend more it may be difficult to revise at this point. We are just starting framing, but I worked with GC and tile setter, plus plumber, to ensure they understood my vision for curbless before the slab was done. The entire bathroom floor was dropped down and sloped and the shower area slab was also dropped down an additional inch and sloped.

### RE: understanding shower curb height

 It all depends on how large/long your shower is and where the drain is in relation to where you enter the shower. Moving a drain pipe is possible depending on where you are in the building process. Google "linear drains" and there are videos that will explain things a lot better than I can. For curbless, the shower drain has to be a certain slope measured from the door entry into the bathroom. The whole bathroom gets treated as a "wet room" with several code requirements, and the whole floor slopes to the shower drain. Costs more. For a curbed shower, the bathroom floor can be level, but the shower drain needs to be a certain slope measured from the curb. -Babka

### RE: understanding shower curb height

 I have seen some bathrooms that have a curbless shower but are not wetrooms. But the showers are quite large so I think that allows for the required slope to be contained within the shower floor. This one from houzz is not a wetroom and even has wood floors. When can I move in? Sigh.

### RE: understanding shower curb height

 They're also doing our shower floor next week; I think we're set for a 4 inch curb. Seems like it would be a real pain to create the structure for curbless. Even on crutches I could deal with a 4 inch curb. I couldn't do it from a wheel chair, but at that point I'd head off to the rehab home anyway. Bbstx - I'm headed for my first tkr after we're in this new house...have you talked to your PT and/or orthopedic surgeon about aging in place ideas? My new PT clinic told us where to put grab bars, based on the layout of our new bathroom.... But I am also curious how a shower could overflow and not have anyone around to be aware of the problem. Are the code people thinking if the sewer backed up, kind of like the toilets that can back up and over flow?

### RE: understanding shower curb height

 bbstx - I stayed in the hospital overnight after one of my knee operations - it was nice. Inpatient PT, all of those inhouse assisted devices that I didn't have at home. But I think I can do outpatient rehab for the tkrs...the PT clinic is about 4 miles from our new house, and I'll have a walk in shower, etc - things I never had before (I do NOT have "virgin knees"!)...they're most concerned about my right knee, so we haven't made any plans at this point for the left one. I can't have MRIs, so I may suggest that they at least scope the left one when they're replacing the right one. Enhanced CTs are as good as we can go - and they hurt!... I need to get through construction of this new house - we planned it with aging in place and bad knees in mind. I can enter the house without stairs, and there are no stairs inside. MB will have grab rails - very nice ones! - a raised potty...I could use those rails right now! Anyhow, we are GCing it ourselves, which is crazy. I don't have a date for the tkr - probably close to February...we have to move first, and install closet systems, shelves, etc.

### RE: understanding shower curb height

 Could someone please explain all of this to me (including how there is going to get to be 4" of water in the shower and I'm not going to realize the drain is stopped up and turn off the water)? But I am also curious how a shower could overflow and not have anyone around to be aware of the problem. A person falls or passes out in the shower and lands on top of the drain. If they cannot get up because they are injured or unconscious, their body covering the drain will prevent it from draining properly.

### RE: understanding shower curb height

 deke, I couldn't argue with that scenario at all. However, if that is what has happened, the fact that the water may rise above the shower pan is the least of my worries. It might even be argued that a 4" curb would keep the water shallow and thereby might help prevent drowning. (Ok, I threw that out there, but please don't let this disintegrate into a discussion of how little water it takes to drown. We are just playing with hypotheticals here.)

### RE: understanding shower curb height

 Our curb is not quite 4" up from the floor outside the shower, and that is with a top piece that is 1 3/16" thick from our crema marfil counter slab, done to avoid grout lines on the curb. If I'd had them use tile on the top of the curb instead, it would have been a bit lower. The shower floor is stone tile, with rubber membrane underneath. So, a low curb using standard construction methods is definitely possible.

### RE: understanding shower curb height

 Thanks, bethinnc. I think he's just trying to throw obstacles (no pun) in my way because it will require him to think about what has to be done instead of just going on auto-pilot.

### RE: understanding shower curb height

 The only requirement for a curb height is based upon the height of the curb top when compared to the shower drain. The top of your curb needs to be 2" minimum higher than the drain. One way to visualize it is if the shower drain were to get plugged, you'd have at least a 2" water depth at the drain before water flowed over the curb and onto the unprotected bathroom floor. If you use a typical CPE of CPVC shower membrane set on sloped, deck mud, with that membrane then covered by a tiling bed of deck mud, then tile on top of that, you're looking at about a 4" tall curb when comparing the curb height to the bathroom floor outside the shower. If your guy is using one of those (CPE or CPVC) membranes, make sure the membrane gets placed on sloped deck mud. The membrane itself has to be sloped for it to meet code. Putting the membrane on a flat subfloor and then putting sloped mud on top of the membrane is an often-used shortcut, and it's also a code violation. Again the membrane itself needs to be sloped. If you use a topical membrane like Hydroban or RedGard you can lower usually that 4" by an inch or so.

### RE: understanding shower curb height

 Thanks, mongoct. Can you give me a cite to the code section covering that? Not that I doubt you in the least, but if I have to get into an argument with them about this, I'd like to know exactly where to find the code section. My town uses the 2006 ICC Building Code.

### RE: understanding shower curb height

 If your guy is using one of those (CPE or CPVC) membranes, make sure the membrane gets placed on sloped deck mud. The membrane itself has to be sloped for it to meet code. Putting the membrane on a flat subfloor and then putting sloped mud on top of the membrane is an often-used shortcut, and it's also a code violation. Again the membrane itself needs to be sloped. mongoct - You are talking about the preslope correct? Not having one is not necessarily a code violation. When we built, we found out that in NC not all counties adopted that part of the code. Of course, I did not find this out until after the membrane was installed flat and had to pay to have it taken out and have a proper preslope done.

### RE: understanding shower curb height

 We just put a shower in. I am not there to measure the height. We did cap it off with a piece of quartz that increased the height. As far as when would water ever over flow over a 4in curb. It happened to us this summer. On vacation my daughter after having too many drinks took a shower and sat on the drain. It was a huge bathroom with a walkin shower with a curb. It flooded all the way out into the hallway. So under normal circumstances it most likely would never happen. But if you go to Jamaica have way to many drinks and then decide you want to take a shower and sit down in the shower, it can over flow and flood. Also you might notice the bad tile job on the wall. Just something to avoid and get a good tile installer. Ours had 12 years experience and we even went and saw a job he did. We had everything drawn out on paper except that wall to the right in the picture. So my advice is have good communication with the tile installer on the lay out of any tile.

### RE: understanding shower curb height

 Funny story, robinle. I think under those circumstances, you would have gotten the same results with a 6-inch curb.

### RE: understanding shower curb height

 What about if you use a linear drain? You can sit on the shower floor, but you can't block all the drainage (esp. if the whole thing is along a wall.) We thought we would have to have a step-down into our shower (didn't want a curb) to get the 2 inch drop. But it seemed like that would be more of a stumbling hazard, so we didn't really want to do it. Our contractor talked to the inspector, who told him that we could go curbless with the linear drain and as long as the shower floor slopes appropriately, the 2" requirement would not apply. It makes sense to me, but I don't know if it fits will the letter of the code or is open to interpretation. I don't see how you'd close off all 5 feet of linear drain with your body even if you tried!

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