Squeaky, Moving Bathroom Floor, Cracked Shower Pan Tab 400

vhollow

The bathroom floor of our 2018 Tab 400 has moved and squeaked from the time we bought it in October of 2017. In the summer of 2021 the shower pan/floor cracked near the toilet.

Initially I planned to stabilize the area by drilling tiny “stops” on the cracks, then screwing the floor down tightly to the plywood subfloor and filling in the cracks.  But, with the drill bit penetration, I discovered there was a gap between the shower pan and the plywood. Not knowing what was in that gap, I decided to cut out the cracked area and patch it back in place.

I discovered that the shower pan/floor has about a 1/2 inch polystyrene foam layer glued to the underside. This layer floats on the plywood substrate. Over time, the polystyrene compresses, exacerbating the flex of the shower pan, which, in our case, resulted in the shower pan failing and cracking in a high-use spot near the toilet. Note that there is no backing at all under the pan where it curves up towards the toilet platform. Note as well that both the compression of the polystyrene and the gap between it and the plywood are visible in the next two images. It seems to me that the design of this floor, flexing, and with polystyrene subject to compression under it, is poor, and may well result in failures for other owners, if this design was continued after the early production units such as the one we purchased.

Note in the following images that the foam is both compressed and cracked down the middle, when viewed upside down, under the cracked area of the shower pan.

I began my repair by gluing in wooden shims in the area lacking foam, near the pan edge and toilet platform. I also removed the cracked foam and replaced it with a high-density weather strip.

I stabilized the entire area of the cracked floor, and the area of most flex in the floor, by counter-sinking (carefully, as the floor is only about 3/16” thick) stainless steel screws, bedded in generous quantities of clear silicone. I grooved the cracks and cuts into v shapes and sanded around their edges. Then I filled all gaps with clear, two-part, relatively fast-setting, epoxy resin. I did the work at about 50 degrees Fahrenheit, so the glue would penetrate the cracks, but stay thick and set on top of them as well. Epoxy resin putty would also work, but I wanted some penetration of glue below the cracks for added strength.

I chose not to sand the glue down afterwards, because the slight mounding adds to its strength. I then covered the entire patched area with non-slip, adhesive vinyl, cut from a sheet designed for use in a bathtub. Finally I covered the entire repair with a fitted rug. The latter is made by buying a larger rug that comes with a binding, removing the binding, cutting the rug to fit, then sewing the binding back in place.

Denny16

Nice job, we have a wood slat cover over the washroom floor in our 2018 TaB400, which distributes the weight to the edges and across the middle of the shower pan.  We have not had any issues with the pan cracking, but good to be aware of the possibility.  Thanks for posting the issue and your grand solution. 
cheers

[Deleted User]

The floor in my brand new 2022 400 squeaks horrible! My 2019 didn't do that. It's so bad I thought something was broken but I looked under there and it looks OK. I see some pieces of 2x4 supporting in some spots so I may add another piece. 

kottum

TabbyShack, more specifically, are you talking about the entire T@b 400 floor, or the floor of the shower?

[Deleted User]

Just the shower floor. Sorry I wasn't clear on that.  

vhollow

Thank you, Denny16, for the compliment! I did a temporary repair first, with white duct tape, and found it surprisingly easy to live with. Eventually I felt compelled to try something more durable. Wooden slats that distribute the weight are a good preventive solution too; but too bad one is even needed!

Re TabbyShack, as far as I can tell the plywood subfloor for the bathroom doesn't move or squeak in my trailer. The shower pan, made of plastic, does, as it floats over the plywood with polystyrene in between. Adding bracing under the subfloor doesn't seem like a bad idea, the only downside being that it may make it more difficult to access the drain plumbing, and may slightly decrease the amount of heat that radiates from the Alde fins under the floor out into the main part of the trailer. A good deal of that heat is probably absorbed above, into the bathroom floor itself.

kottum

Denny16, the wooden slat floor cover to distribute the weight more evenly across the bath floor looks to be good preventive medicine.  Is this an item you purchased or something you made for it?  

Thanks mentioning it and thanks to the O.P. for his clearly posted repair.  It looks like the foam functions as a floor insulator, but not much of a floor support.
 
Doug K

Denny16

kottum, A custom made one is very doable to fit the odd shaped area,  but ours was a commercially available item (that can be rolled up), the seller had added.  Here is a shot of it:

I plan on making a larger one to fit the area better, especially after seeing what happened to vhollow.
 Cheers 

kottum

I found there is vertical movement of the shower floor (maybe 1/4") when I press down with my hand on our new 2022 T@b 320s BD (mfg date  Feb 2022) shower floor near the drain.  So I went over to the Nucamp dealer in Mesa and tried three new 320's and one new 400.  They all have similar movement when pressed down.

I looks like the foam insulation under the floor is not of sufficient thickness or strength to fill the space.  This is what I would call a manufacturing defect if it results in a cracked floor over time.  Nucamp ought to be looking into this to maintain their higher standards and pricing of construction.

Doug K

[Deleted User]

I noticed an issue on my 2022 400 as soon as I stepped into the shower. It was extremely loud to the point I was reluctant to step in there again. I had some scrap wood and I just stacked it until I found the sweet spot and it stopped the movement and sound immediately.  

Denny16

No, the shower pan/floor has about a 1/2 inch polystyrene foam layer glued to the underside, see the photos near the beginning of this discussion. Polystyrene is a good insulation, but is not a structural material, it will compress with weight placed against it.  A rigid closed cell foam would have been a better choice.
 Cheers 

vhollow

Yes, rigid closed cell would be much better. As I noted with my repair, the current construction, if it the same as in my 2019 400, will result in more floor failures such as in my unit. Thanks, Denny, for paying attention to the original post.

Maple_Geek

Checkout these Youtube videos that provide another option of dealing with this issue:
https://www.youtube.com/watch?v=OSmotwjvuGo
https://www.youtube.com/watch?v=VTFmJbjbPRQ
https://www.youtube.com/watch?v=jsKApHNJqgI

Denny16

Interesting idea to repair this issue, but good luck getting the shower pan off, if it ever does crack.  The foam is going to bind this in place. 

Cheers 

den1jen

2023 Tab 400 and I too have a squeaky shower floor, so took access cover off and did notice that you can push the drain up 1/4" to 3/8".

I might try using a bamboo/teak mat as @Denny16 has and eventually might make a custom one out of cedar since we have a ton of it on our place. 

My other thought remove the drain and see if can install shim material to raise the floor to add stability; but not so it won't drain properly.

I am curious has anybody pinged the factory to inquire on any suggestions to remedy it?

Thanks