I had a shower enclosure installed in my basement as part of additional work performed after reconstruction of a fire. (Something nobody should have to go through. We are 18 months from the original event & 12 months from moving back in.)

As a result of the main basement drain being moved and the new concrete slab not sloped toward the new drain (and a faulty pressure release valve on hot water tank - actually 2 of them) I've ended up with standing water behind the bar & lavatory and under the shower enclosure and with it black mold. (The mold test results are coming next week) The water was hitting the floor & maybe 10% going to the drain while the other 90% went under the shower & over to the bar area, sitting under the cabinet (because the tile prevented it from rising to a level where it was actually visible)

The mold company also told me that the floor of the enclosure should have been set in concrete or "hot mix", which I assume from my research to date meant mortar, but maybe he meant asphalt.

The contractor, when told this, said the enclosure had "legs" (it has ridges on approx 6" centers or something like that (I have not measured), that it DID NOT need to be set in anything & could be set directly on the floor because it was "self supporting" and that the mold guy should stick to his expertise. (I can't stand this guy, but was not going to argue without supporting facts, but the mold guys do reconstruction & my assumption is that they fix F-ups like this all the time.)

I have also talked to a builder friend that backs up what the mold guy says.

My question: Sorry it took so long to get to it is... are these types of enclosures supposed to be set in mortar? I can't tell who the manufacturer is & will probably have to do some digging to get to their specific instructions, but I'd like to stick it to this contractor because trust me he deserves it. I'd be happy to post pics of any of the plumbing/installation an expert wants to see (It's wide open now, the relief tube has been tied to the drain, the floor is drying out, but the foundation still appears wet under the enclosure floor and the foundation concrete saturated behind the bar. I don't want it closed up improperly just to satisfy the insurance company & the contractor only to find out 5 years from now that I've been culturing mold under there)

Just FYI - I've already decided that remediation will follow the mold companies recommendations, regardless of what either the contractor or insurance companies think and if I have to sue the contractor and or insurance company I will.

Oh, and by the way, I've never actually used this shower. The only time it's ever been on was to clean up the huge mess the drywallers made and of course, I was the one that had to clean up the mess.

What does the manufacture recommend? While we have "puddled" mortar under some shower bases that do not have support legs We don't pack the base full of mortar or cement for a solid underbase and if the base has supports we don't feel that we must add to it.

"As a a result of the main basement drain being moved and the new concrete slab not sloped toward the new drain (and a faulty pressure release valve on hot water tank - actually 2 of them) I've ended up with standing water behind the bar & lavatory and under the shower enclosure and with it black mold. (The mold test results are coming next week) The water was hitting the floor & maybe 10% going to the drain while the other 90% went under the shower & over to the bar area, sitting under the cabinet (because the tile prevented it from rising to a level where it was actually visible)"

This tells me that if any blame is to be placed it should be placed on the cement men that failed to slope the floor the correct way.

One other issure comes to mind. Why did the T & P valve fail? Was it because you have a check or backflow preventer installed on the house service without a expansion tank being installed on the cold water supply to the heater? If so, it would seem the original fault lies with you. Regards, Tom

Thanks Tom. I appreciate your time. I'm not sure what the manufacturer recommends because I'm not sure exactly who it is yet. (It may take some digging) I was hoping an expert could tell me whether it was standard to mortar it or not, especially given that it's a concrete basement floor. I think if my 240 lbs gets in there it could be trouble. Those legs are thin enough that I can't see them supporting the floor of the shower properly.

I would agree that the concrete placement was poor, of course there was no way to check it because all utilities were turned off.

I'll have to check on the backflow preventer, there is no expansion tank and there is no drain pan either, but my "City" while adopting the 2003 International Code, omits the section on water heaters so I'm not sure whether they actually have any standards on them or not. I can say that any problem in that area is not my fault... I'm not the contractor. He's the licensed plumber & did the installation not me. I'm just the dumbass homeowner, all I've ever done is replace pipes under a sink that were clogged and I once reset a toilet, with help.

The part that bothers me is that the contractor wants to push off the blame, the insurance company wants to open a new claim & subgrogate against the valve manufacturer and what I think is going to happen is that the valve manufacturer is going to say the valve did it's job... you screwed up by not making sure it drained properly. The valve is just there to prevent the tank from exploding. They've since installed an elbow & taken it directly into the drain.

I could tell dozens of stories where other subcontractors did poor work that had to be re-done or that cost me $ after the fact. Heck, I thought the electrician was going to start a fire when he was trying to install the doorbell (we have a wireless doorbell)

Thanks again! I'll look for the check or backflow preventer.

It would seem that there's enough blame to go around. The cement men for not sloping the floorto the floor drain. The plumber for not installing a expansion tank if he indeed installed a check or backflow preventer and the builder/contractor for not realizing that this work should have been completed before the house was C.O.ed. I take back my ststement that any fault lies with you. If you weren't informed that a expansion tank was needed then the blame rests with the plumbing contractor. Regards and let me know, Tom

It would also appear there is a supply side leak somewhere as there is still water on the floor (not much, but it should be completely dry by now)

"The part that bothers me is that the contractor wants to push off the blame, the insurance company wants to open a new claim & subgrogate against the valve manufacturer and what I think is going to happen is that the valve manufacturer is going to say the valve did it's job...you screwed up by not making sure it drained properly. The valve is just there to prevent the tank from exploding. They've since installed an elbow & taken it directly into the drain."

All this could have been avoided if the plumber had only installed the T & P valve drain line the way our code calls for it.
We run all our water heater T & P discharges out side the unit in a 3/4" line.
It is against code in my area to discharge , sump pumps, Rain water run off, AC condensate lines, water softener discharge and T & P discharge into city sewer lines. The reason being that the utilities company has to process the discharge just as if it were sewage and that ups the cost back to the customer.
My take on this? The T & P valve did the job it was designed for. Suing the manufacture will be a waste of time. You got a lousy installation. Go after the builder and the plumbing contractor. Please keep me in the loop on this and let me know how it turns out. Regards, Tom