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WCohn, Journeyman Plumber
Category: Plumbing
Satisfied Customers: 1099
Experience:  Journeyman Plumber/Estimator
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Is it possible to retrofit some sort of foundation material

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Is it possible to retrofit some sort of foundation material under a stall shower? We have a modular home with 2 1-piece molded shower units and evidently no foundation material was installed during construction. It seems that weight in the shower (I am about 235, my son about 275) causes flexing of the floor that allows leakage around the drain. I'd prefer not to have to replace the entire shower stall if there is a fix that will stop leaks that are ruining the ceilings of the floor below.

Hello my name is ***** ***** I look forward to helping you!

So you are just trying to eliminate flexing or fixing the leak?

Customer: replied 11 months ago.
When I tried to reply last night it was sending me to another plumber, asking for a 2nd deposit and commitment to pay for the advice. In fatigue and frustration I went off to other things for the remainder of the evening.
The NEED is to stop the leaking as it has ruined the ceilings below. Long after we purchased the house we discovered some dishonesty on the part of the seller (sadly VT does not yet have full disclosure laws) as to the nature of the previous leaks. Currently the ceilings below both showers have large holes cut for access, but the sheetrock was already ruined by the leakage.
All of our attempts to properly tighten the drain nut, reseal around the drain & prevent future leaking have failed, and in the process of these attempts we discovered that the leaking only occurs when there is weight in the shower stall which flexes the floor. By observing this we have concluded that the problem arises when the floor flexes and allows the seal around the drain to be broken, and no amount of tightening the nut or using sealants around the drain provides long term satisfaction. I have noted also that there was no foundation material put in under the stall when the (modular construction) house was built. In looking through instructions for installation of similar 1-piece molded units I see that it is common, or even recommended to use plaster or thin set mortar underneath, and I am wondering if there is a way to 'retrofit' this material without damaging the shower unit.
To directly answer your question, fixing the leak is paramount, but I think the best way to do this well be to eliminate the flexing that causes it. There are NO cracks in either the shower floor or the drain pipes, so it is all coming from areas where seals are breached in the course of flexing.

If it is sealed properly the flexing would not cause it to leak. I would replace the drain. I'll upload a picture of a great drain to use

Called a JackRabbit. For repair work like you have.

Customer: replied 11 months ago.
Looks like it might work, thank you. It addresses the clearance issues I've been finding. Just no way to get adequate torque on the ones we have the way they are tucked up into the joists.
I recall our heating guy when we lived in CT using a wonderful gadget, I think called Shark Bite, to repair some burst heating pipes after a 10 day power outage. I'll give this a try, sure beats replacing entire shower units.....

I'd appreciate a five star rating for helping you and tips are great as well.

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