Shower pan choice


Senior User

I have no experience with the newer systems. The last shower I put in was just a simple multi piece fiberglass one for guests. But I have a couple observations I hope are useful. First, the fiberglass one went in to replace a mud pan shower that failed because they used a galvanized steel pan. That doesn't say anything about the longevity of a copper or possibly a plastic pan. With a good pan, I think a mud bed can last indefinitely. The mortar will not fail if the house doesn't move but hairline cracks can create leaks. That is the job of the pan. If it does not corrode away, the shower won't leak. The right plastic is probably lasts indefinitely but buried in mortar isn't necessarily a good environment for plastic. The kind of leak that caused me to tear out the mud bed shower might not even have been noticed over a crawl space. It was pretty small, in other words. But when it drips onto the drywall ceiling of the kitchen it is a lot more noticable than a few drops into the crawl space.

You know your layout a lot better than me, obviously. But don't forget that you can add posts in the crawl space instead of sistering joists. Might be easier to put a beam or two across the area, put in some pads and posts.



Mote watching videos, more thinking.
Leaning to the VIM system. No structure unless need to box to clear the drain. I might still be inclined to sister the joists just to improve overall strength. I am a big fan of overkill. One of the joists was already ( poorly) sistered as a leaking drain rotted it a bit. It will get redone better. The pan system is about a grand, but allows plain old durarock on the walls and assumes 1/4 board on the rest of the floor with just the liquid membrane. Actually cheaper than the other two systems when all totaled.

I was looking at some solid surface pans. None of them explain how to do a seal between the tile floor to the pan surface. Just an RTV bead I don't think I would trust. Not reassuring for a $3000 to $4000 product.

I think one can buy the preformed Shulter inside and outside corners instead of slitting flat tape and use with any system. Their or Laticrete gaskets for the shower heads and valve may be better than the old foam rod/RTV filling I have done in the past.

I think most modern mud pan membranes are EDPM. With no UV, good for a few hundred years.
Drain seal system is still a problem. Some new ones with weep holes are better.
An alternative is to do the dry pack pan, but use a liquid membrane on top. Again, drain is the vulnerable point.
All houses move. After I had the crawl space sealed and it dried out, I noticed a little settling ( obvious with a brick exterior)

People tend to not notice little leaks. Purchase inspection identified both showers leaking. I just found one toilet drain was never glued and would produce one drop occasionally. With a big white plastic sheet, it is easier to notice a drip.
Adding a pier is possible. I noticed when they put tile in the kitchen, they added a pier. Don't know if they did a proper footing, or just a block on the dirt ( I suspect) There is a pier pretty close, so overall the floor does not seem to move much now.

Comment that makes sense: Do a center drain as the singe slope for a trough drain can cause an accessibility chair to roll. Center drain is self centering. Total less slope as well.

Also waffling on a conventional vs. all mount toilet. Wall mount gives me 9 inches more floor space, better for a "wet" room floor, easier to clean, but does cost over a grand and I wonder on flush quality. They have a 3 inch drain. Kind of spoiled with the new Kohlers with the bigger throats that flush so much better. If you have one you will know. If not, you don't know what you are missing. I have not measured, structure may make it a moot point as the wall might be right over the main beam.

While my brain is frying over this, guess I had better get to designing the vanity cabinets.

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