Shower floor popping / squeaking?

[Michael J Evans]

Hi All,
We have a stand up shower in our master, it is a all plastic molded type. I've noticed for the past few months when I step on one side of the drain I get loud pops / squeaks from the floor of it moving. We've lived in this home about a year now and I don't always remember this being a issue. I had to replace the drain in it a few months after we moved in as it was leaking down the side of the drain pipe (externally). It had one of those quick install drains with the nut to tighten underneath. I replaced it with a jack rabbit type and used caulking on the inside (where you stand) to seal that part. as I was underneath the house, my wife set the new drain into the caulking but then had to remove it and re set it again. I was too lazy to crawl back up and re caulk it. So I tightened it from the bottom came back up, noticed the caulking seemed to have good squeeze out and called it a day. I checked a day later to make sure no leaks.

Now I'm wondering if I over tightened the new jack rabbit style drain I put in and squeezed out all the caulk or caused some kind of crack I can't see? I do remember getting it really tight as I wasn't sure how much to tighten the "jacking" bolts. I've been under the house numerous times the past few months since I started hearing the floor making these sounds and there is no leaks or anything. I pulled the insulation down and checked the plywood and couldn't see any signs of moisture or anything, but I don't think if it did have some type of minor leak that the plywood wood be wet on the bottom if there was some standing water on the top? I swear when I stand on it and move around that I can hear some water moving under my feet when I move around... I'm kind of at a loss of what to do, besides pulling the whole thing out, I really don't want to dive into something like that, nor do I even know how to start.

Oh and this only happens on one side of the drain, the other side is totally solid.

What do you guys think, is this common for injection molded showers, it is just the plastic flexing?

Any help or ideas is appreciated. Thank you
Michael

[Bill Dufour]

No idea what a jack rabbit drain is. If it was a metal drain pan I would say it should have been set in a mud bed for support. maybe shoot foam insulation under it for support. But make sure it is the right kind that will not collapse under load. Sounds like you have a basement under the shower for access?
Bil lD

[Malcolm McLeod]

... maybe shoot foam insulation under it for support. But make sure it is the right kind that will not collapse under load. ...

Might do fine, but I'd recommend a minimally expanding foam. If any foam expands too much, it may both stop flex in the problem area, but also lift a small area of the shower floor, and so simply move the problem to another area.

Self-leveling underlayment might avoid the 'lift' potential - - IF you can get it where it needs to be?

Also curious what caused it- - Maybe the drain applying torque/unequal load - flexing the shower floor up (creating a gap under part of it)? Maybe the water leak caused the sub-floor to swell, lifting the side opposite the 'pop'? Maybe not the sub-floor at all, just a wall shifted and pinched the shower floor - bowing it up slightly?

Depending on how much it's moving, it might last forever (just annoying) - assuming the plastic is not 'over-stressed' (modulus of elasticity, melt index, and all that gobblety-speak). But if you suspect there's water under it (on what sounds to be pier-and-beam), I'd go so far to wreck the shower out and re-do it. Water is insidious.

[Michael J Evans]

No idea what a jack rabbit drain is. If it was a metal drain pan I would say it should have been set in a mud bed for support. maybe shoot foam insulation under it for support. But make sure it is the right kind that will not collapse under load. Sounds like you have a basement under the shower for access?
Bil lD

Hi Bill
No basement just a little crawlspace. I cannot shoot any foam under without removing the molded tub. If you Google a jack rabbit shower drain it basically is a remodel type drain. I couldn't spin a wrench in between the floor joists? To tighten a new drain onto the pipe. To basically a jack rabbit style has a threaded nut underneath that you tighten best you can and then it has 4 bolts that you then torque which applies counter pressure to the top and seals everything. Actually a pretty slick idea.

[Kev Williams]

Your extra tightening may have actually twisted the plastic floor slightly, creating , I don't know the technical term, an 'expansion bubble'-? --where you've pulled the plastic tighter in one area, creating a looser area in the opposite area, resulting in a slight convex bubble; when you step on the bubble it pops down, loudly, into a slight concave, and returns back once your weight is off if it-- IF this is the case, moving the bubble downward would likely move the drain pipe slightly, which would account for the squeak...

Just my guess! ;)

[Bill Dufour]

drill some holes through the sub floor then shoot foam in those holes.
Bil lD

[Ken Combs]

drill some holes through the sub floor then shoot foam in those holes.
Bil lD


That gets my vote too. Just be sure to get the foam intended to seal windows as it won't over expand;

[Thomas McCurnin]

Those Pre-Fab bases are supposed to be set into a dry set mortar, which was not done, or it was concrete, and it cracked.

I can't think of a good permanent fix. I don't think foam will be able to sustain the concentrated weight of a human being. But no harm trying I guess. I think you'll have to pull it out and re-set it.

John Bridge Tile Forum would be the place I would go for an answer.

[Michael J Evans]

Thanks everyone. I will probably start with removing the drain and re installing it and see if that fixes it. If not may call in a plumber to get their thoughts. We once had to evacuate a rental due to sever toxic mold, due to hidden leaks. So I am very cautious of any leaks.

[Thomas McCurnin]

I doubt it’s leaking, but you could stress crack the fiberglass base. You can plug the drain and fill the shower with water up to the curb and wait for 24 hours to perform a leak test.

In a prefab base, the waste drain pipe is bolted to the underside of the pan, so about all you’ll be able to do is remove the grate. I don’t think anything else will come off.

It might be time to replace that base, or as my dad used to say, ride the horse until it bucks you, e.g., use the base until it fails. Replacing those bases is a pretty cheap fix.

[Michael J Evans]

I doubt it’s leaking, but you could stress crack the fiberglass base. You can plug the drain and fill the shower with water up to the curb and wait for 24 hours to perform a leak test.

In a prefab base, the waste drain pipe is bolted to the underside of the pan, so about all you’ll be able to do is remove the grate. I don’t think anything else will come off.

It might be time to replace that base, or as my dad used to say, ride the horse until it bucks you, e.g., use the base until it fails. Replacing those bases is a pretty cheap fix.

Thomas
Good idea on the leak down test.
I'm not sure I understand the rest though, my shower and the base are all 1 piece of molded plastic .The pipe is not bolted to the drain or base. I had to lower it to install the new drain. The drains have a built in compression coupling that uses a combination of a brass and rubber ferrule to seal the drain pipe. You tighten the drain onto the pipe from the top via a key that fits in the brass ferrule.

[Thomas McCurnin]

Ah....

Its a one piece shower, not a surround and base in two parts. Most are two pieces--a surround and a base.

Nevertheless, unless you take the whole thing out, I'm not sure how you trouble shoot it, to remove the drain and look under the base. If you can remove the drain and look under the base, then do that, then great shove some drypack mortar mix in there to support the floor.