Shower pan flex at wall

[wanderso]

While inspecting my shower in my fleetwood jamboree 2001 class c, I noticed that the shower pan has a great deal of flex along the wall, allowing for a gap under the caulk. I expect this will allow water to get behind the wall. What have folks done to stabilize this? With how tight it is, I have thought about putting expanding foam under the base but the height appears too tall to fill. Thoughts? Sample photos attached where I pressed down on the shower base to make the gap appear.

[RV Wizard]

Inspect the floor under the shower. Can you strengthen the shower pan support to prevent the surround and pan gap? Once the real problem is repaired you should be able to clean and reseal the seam and it not be an issue.

[wanderso]

Thanks. I pulled the inspection plate and the supports and floor are in excellent condition. The flex seems to be centered on the thin fiberglass perimeter and not the base of the tub. Unfortunately I don't see any easy way to shim the perimeter. Hmm.

[wanderso]

Here are some photos of the support area as taken through the inspection hole.

[Mageksl]

Your shower pan may have come loose from the wall which allows it to flex. If you can take the walls down you may be able to reattach it. Using some limited expanding foam under the pan and above the support in your photo should keep it from happening again. If you can't or just don't want to take the walls down I would try just using the foam. Most fiberglass tubs and shower pans in residences are screwed to the walls and the bottoms are supported by a type of grout, different from tile grout, that is floated in after they are set square and level. The foam should support the pan for you. Use as much as you can get in there.

[cmpncrsaider]

Mageks idea will work but like he says make very sure You use the limited expanding foam, any of the other foams will lift the pan right up and will be very hard to fix!

[wanderso]

I will give it a shot. No easy way to remove the shower walls; may have to pull the pan itself.

[cmpncrsaider]

One tric with the foam, get a 2 or 3 foot peice of romax wire, pull the conductors out of the casing, slide the casing over the applicator tube so you can slide it back under shower pan, as you start pumping foam under pan slowley begin backing out as you continue pumping, have a couple cans ready to go so you can keep things moving or foam will clog casing (makeshift application tube). I,ve done this inside plaster house walls where electric boxes have come loose, works very well, but you gotta keep it moving. Goooooooood luck! Oh 1 other thing!!! this foam is the stickiest stuff on Earth and doesn't come off!!! take the time to really set up work area protect everything! (Notice all the exclamation points!!) You guessed it I've got it on myself before, has to wear off over time.

[chief02]

Your shower pan/tub should have about a 3" flange that gose up behind the wall. That is probabaly why there are no leaks or water damage

[wanderso]

It's looking more like I will need to pull the shower pan so that I can properly re-seat it using expanding foam against the supports. Any tips to achieve decent removal and replacement? I expect that I will have to disassemble the drain, among other things.

[RV Wizard]

Pull the faucet off the shower surround if you need to and then pull the surround. Disconnect the drain at the trap and pull the shower pan. Make repairs and re-install in reverse order.

[wanderso]

Ok -

Removal of the pan wasn't hard. As an aside, amazing that fleetwood hadn't even cleaned up their wood shavings on the floor in the RV from the factory (see left). (I will clean it)

I noticed after removal that there is no styrofoam on the "step" side of the pan, which explains why there is so much flex (gap between that and the wood support). On the main pan, the foam has also decayed a little bit.

So to add support, I'm thinking of adding slightly thicker styrofoam on the main pan area and adding styrofoam on the other side. I suppose expanding foam could be an easier alternative to consider?

The tub has yellowed a bit. If I had my wish I would change to just a shower base instead of this phony "tub", but all that I can find aren't the 24x38 size of this one. I did find one tub that doesn't have the step, but the drain is in the center (plumbing re-orientation) There are some tub surrounds that can be installed that are 24x38 and would be a nice upgrade, but the yellowed tub would be more noticed. (painting probably will chip; I've seen other tricks to de-yellow the plastic with mixed results that I've seen. Hmm....)

One other thought - you will see that the prior owner used caulking on the trim that holds the tub in place. He placed caulking both on the top of the trim and on the bottom. Since the tub has a rim that prevents water from reaching the wall, isn't it smarter to NOT place caulking on the lower portion so that any water that gets behind the metal flange can just air dry?

[RV Wizard]

If you add styrofoam, you will need to adjust or modify the plumbing drain height. Make sure you have head clearance for the surround. There is no need for sealant around the top edge of the tub (where it is mounted to the walls) as the surround bottom will over lap this when installed.

[wanderso]

You're right about the drain height issue on the plumbing as a possible 'gotcha'. I suppose if I even just replace the existing with the same thickness that has since compressed, that could limit that problem. I measured for the surround and have about 1.5 inches to spare which is good. Are these surrounds normally installed using liquid nails (or the like) to install to the RV wall? (this is the tub surround adhesive LIQUID NAILS? Wall Adhesive | Fiberglass Reinforced Plastic Panel ) The concern I have there is that it will certainly be a permanent install and difficult to remove the base in the future if there is any sort of issue. That said, I'm not a big fan of the stuff on the shower wall at the moment (a vinyl like material that has a bubble where there once was a leak in the roof that bled down the interior sidewall)