Bathtub support loose.

[Tlhfirelion]

Hello. When using our fiberglass bathtub/shower recently, we’ve noticed the support rings under the middle seem to have broken loose from the adhesive. So as you move around in the shower, you can hear and feel the rings slipping underneath you.

I’m on a crawl space, so is there any way to fix this without ripping the bathtub out?

Thank you in advance for your assistance.

 

[Reach4]

I’m on a crawl space, so is there any way to fix this without ripping the bathtub out?

You could drill some controlled holes under the tub and squirt mortar.

If the holes are made bigger using a hole saw, you could stuff balls of mortar into plastic bags and stuff them around the holes. I don't know what dimensions you would be dealing with. It would be a shame to drill a hole in your tub. I would need to devise some form of stop where you are not trying to control penetration by hand.

I am not a pro, and I have never done that.

 

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[Tlhfirelion]

You could drill some controlled holes under the tub and squirt mortar.

If the holes are made bigger using a hole saw, you could stuff balls of mortar into plastic bags and stuff them around the holes. I don't know what dimensions you would be dealing with. It would be a shame to drill a hole in your tub. I would need to devise some form of stop where you are not trying to control penetration by hand.

I am not a pro, and I have never done that.

Thank you for your reply. The idea of drilling that many larger holes concerns me to be honest.

Some smaller holes would be acceptable to squirt mortar as initially suggested. What mortar would be best and what device would I use to squirt it up in there? Would it be best to have the tub filled with water when Injecting Mortar?

Am I correct in assuming that I need to surround the support rings with the mortar to prevent them from moving?

Is a closed cell spray foam an acceptable option? The tub is only a couple years old so tearing it out is the last thing I want to do.

Thanks again for your assistance.

 

[Reach4]

Thank you for your reply. The idea of drilling that many larger holes concerns me to be honest.

I was thinking of maybe two 2 inch,or so, holes made with a hole saw. The pilot drill would certainly be removed once the groove was big enough to keep the hole saw from skittering.

Some smaller holes would be acceptable to squirt mortar as initially suggested. What mortar would be best and what device would I use to squirt it up in there? Would it be best to have the tub filled with water when Injecting Mortar?

Regular mortar, but a stiff mix. I am thinking no water in the tub while poking balls of mortar in, and then adding water once the mortar lumps are in place. Having balls wrapped in plastic would help keep the mortar from drying out before it hardens.

I don't know about the closed cell foam. Might be ideal for all I know. You don't want to try filling the space. You don't want an expanding foam to jack the tub up. Just make some extra supports.

Maybe one of the products, such as a concrete patching, that load into a caulking gun would be suitable.

If you do this, take pictures. Let's hope they show a boring success rather than the more-popular-to-view failures.