Does anyone have any experience building a curbless shower pan? I have built multiple showers and have generally mastered the typical shower pan with a 3"-4" curb but we now have my wife's 91-year-old mother living with us and she has trouble stepping over the curb. We are getting ready to remodel her bathroom to make it more accessible and a curbless shower pan would help.

My first thought is to cut into the sub-floor and joists (2x12) enough to create a 1/4" slope for a 42"x60" shower pan (roughly 1-1/4"). Then add stabilizers between the joists (perpendicular) and new subfloor. This seems like a lot of work! But with our aging population we should see more of them than we typically do.

Someone has to have done this before and could possibly shine a little light...

  • Hello, and welcome to Home Improvement. Interesting and useful question; let's see if someone can answer it. And, big props for taking our tour before posting; few newbies do, even though it definitely helps. Oct 14, 2019 at 23:29
  • What waterproof membrane are you using as the liner? Oct 15, 2019 at 0:16
  • I typically use the PVC membrane, I think it's made by Oatly (sp?).
    – GMisenar
    Oct 15, 2019 at 0:22
  • Are you going to cut additional for the dry pack base? With the PVC sheet, it will seem necessary, but if you used a liquid applied membrane, you will not need the mud base. I have overseen one of these go in but the whole floor was built intentionally 2" low for mud base over PVC membrane.
    – Jack
    Oct 15, 2019 at 0:52
  • Yes, I was going to use the dry pack base (deck mud) with the PVC sheet. The sheeting is only 40 mils, which isn't too significant (obviously thicker than the paint on liner). What I'm trying to do is mitigate the slope and avoid cutting the joists if possible.
    – GMisenar
    Oct 15, 2019 at 15:23

2 Answers 2


To long for a comment My niece is disabled and uses a wheelchair no curb shower pans are easy but remember the pan is now going to be 2-4x the size of a normal shower. We used a glass brick wall on the center to divide the bathroom up because the large unusual size. For her shower the floor has a slope from the opposing wall all the way back to the drain. We considered a speed bump (very slight) to contain the water that may splash but at 7’ felt it would not be needed. 10 years later the shower is still fully functional. One thing my sister insisted on was thermostatic water valves so if she bumped the valve they would not get froze or burned. The valve has required replacement 1 time recently. The rest of the bathroom floor was raised 3/4 or 1 inch I do not remember. For the floor tiles a rough finished natural stone was used so it would not be slippery when it was sealed, my sister says this is both a blessing and a curse it is not slippery but is hard to clean, we added another outlet close to the opening that she can turn on and spray down the floor pushing the water and soap back to the drain. Since it has a minimal slope. Since this is for an elderly person you might consider a fold away bench. I installed one of these many years ago for an elderly couple in a standard shower. I don’t know if they ever dropped it down but they told me it was very nice. So you can go totally curbless but you need the pan to extend beyond the splash zone.


basically you build the whole room like it's a shower (but you only need th waterfproof the floor and the walls near the shower)

usually what's done is to slope the bathroom floor towards the shower drain (either the whole bathroom or just the part near the shower. This is typically accomplished by raising the whole bathroom floor using mortar screed to form the slope.

If you're doing the floor in linoleum instead of tile, you need to rip up the floor and install vallety boards etc so that the floor panels can be cut to slope to the shower drain. the linoleum is welded into a single piece and seals the floor and the base of the walls. then waterproof panels are installed near shower outlet that overlap the top of the linoleum.

If I was to fall, I'd much rather fall on linoleum.

Either way there'll be a small step to enter the bathroom unless you can lower the joists to compensate.

your're planning to reduce the joists. unless you can find an answer in the framing manual you probably need to talk to an engineer. I would expect than you can go to 4x8 and get the same strength as 2x12 (so adding 2x8 beams to the 2x12 beams should be acceptable, but don't take my word for it.

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