We recently had a new shower stall installed. It was hot-mopped, then the floor and side walls were floated, and tiled. I should mention that this shower is located on the second floor.
About two weeks after we started using the shower, we noticed water damage appearing in the ceiling directly below the shower. We called our contractor, who removed the damaged drywall below the shower. He discovered that the p-trap that was attached to the drain collar was cracked; apparently a factory defect. This whole assembly was replaced by chipping out about an 8″ diameter hole around the drain in the shower floor to gain access. Consequently, the tile, concrete floor, and hot mopping had to be removed from this area. I asked our contractor if the floor had to be hot mopped again, and was told no, it could be patched without hot mopping.
Here’s my question- Isn’t our contractor’s fix going to compromise the integrity of the waterproofing? It seems to me that the correct (and expensive) way of permanently fixing this is by removing all the tile, floated concrete, and old hot mop, and redoing it all. All suggestions are welcome. The contractor wants to come out this coming week to do his repairs, and I want to be armed with knowledge.
Replies
"Isn't our contractor's fix going to compromise the integrity of the waterproofing?"
Simply put: Yes.
Concrete is porous. The area around the drain gets the most amount of moisture and therefore should have a waterproofing treatment. Hot mopping would be good as long as it overlaps the new/ old concrete seam and bonds with the old, exposed hot mopping.
"the correct (and expensive) way of permanently fixing this is by removing all the tile, floated concrete, and old hot mop, and redoing it all."
This is one way and certainly an expensive way, but it is not the ONLY PROPER way. Just be sure the tile is removed so as to get enough of a bond between the old water sealing and the new. The water sealing is themost important component of this whole assembly assuming everything else is done properly.
I do not understand why the plumber needed to address this from the top rather than from the ceiling below - since the ceiling got ripped out anyway.The trap screws onto the drain assembly and could have been unscrewed or cu as needed.
Hope this helps,
Frankie
There he goes—one of God's own prototypes—a high powered mutant of some kind never even considered for mass production. Too weird to live and too rare to die.
—Hunter S. Thompson
from Fear And Loathing In Las Vegas
Why didn't they replace just the "p"trap
Shower drains usually have a tail piece going into the trap I can't see why they chose the harder route.
On my current job site I have had to replace 15 "P"traps on tiled showers---- 2 bad traps 4 filled with concrete---- 9 filled with grout
Not once were we even thinking of replacing the drain or touching the water proof membrane.
Do you look to the government for an entitlement, or to GOD for empowerment. BDW
Something is missing. I am thinking that instead of the P-trap having a crack, the drain assembly did. Therefore the whole thing had to be removed.
I also think there wasn't a crack, but rather an incorrect/ faulty installation of the drain flange/ assembly.
What's the rest of the story?
Frankie
There he goes—one of God's own prototypes—a high powered mutant of some kind never even considered for mass production. Too weird to live and too rare to die.
—Hunter S. Thompson
from Fear And Loathing In Las Vegas
I agree, and suspect that the contractor is blowing hot air up Timberwolfe's skirt.
First, someone explain to me how a "hot mop" shower pan ties in with a clamping ring drain, or any other drain used in a tile shower. From what I know, hot mop has been abandoned almost everywhere as a shower pan detail, in favor of rolled membrane waterproofing or systems like Schluter's Kerdi. Clamping ring drains are reliable when used with membranes like chloraloy. I have heard of some old-school guys continuing to use soldered copper that is hot mopped, but that does not sound like what happened here.
Anyway, I bet that what happened here is that the drain fitting leaked where the "hot mop" was supposed to tie in. Otherwise, the contractor and plumber would have been smart enough to save themselves a whole bunch of time and simply cut out and replace the "leaking P-trap". Tearing out tile to repair a shower leak is a desperate situation.
A leaking second floor shower will be a curse forever. If I were Timberwolfe, I would require a leak test of the shower pan after it is repaired. They make the repair to the waterproofing, leave the ceiling open, plug the drain with a 2" test balloon, fill the pan to the top of the curb, and let it sit 24 hours. If it's completely dry below, go ahead and retile, and then test again. The ceiling is not closed until the whole thing tests twice.
I would be looking for a very good tilesetter to repair this, maybe not the same guy that did the hot mop.
what part of the country/world are U in?
might be a regional thing ... but I've never seen a hot-mopped shower pan.
old are copper or lead ... new are rubber membrain or kerdi-type.
with everyone else ... wondering if the p-trap was just an excuse?
how long is the warrenty on the repair? Time will tell.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Jeff-
We live in Orange County, California. Apparently, hot-mopping shower pans is still quite common here. We had another shower remodel about 4 years ago, and it was hot-mopped. Some friends had a new shower installed in their home less than a year ago, and it too was hot-mopped. These jobs were done by three seperate unrelated contractors.
Thanks for your response,
TimberWolfe
well that settles that. Maybe Boris will stop by ... he's a tile guy that works in Cali, I believe.
I've never worked around a hot mop pan ... so I don't have the first clue as to this fix.
Jeff Buck Construction
Artistry In Carpentry
Pittsburgh Pa
The hot mop is definitely a regional thing, as many of us have never, and will never, see that method used in our areas.
There has to be an effective pan to protect from moisture working its way past the grout. A simple test won't cut it since grout leaks are years down the road. A proven method of sealing the pan must be used, and applied correctly.
If the contractor and plumber are doing a fix, then they need to end up with a reliable, continuous pan--hot mop, membrane, metal, or what have you. They are probably tempted to forgo the proper fix since any leaks won't show up until years down the road, if ever.
As to the proper fix for hot mops, I can't say. Maybe it's simple to patch. Maybe not.