Foam support for under tub


Old 06-12-14, 07:46 AM
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Foam support for under tub

We installed an American Standard enamel on steel tub in our bathroom. The tub makes a crunching sound when we get into it. The representative from American Standard came out and said that it was installed correctly, (and basically we just have to live with the noise).

I feel like this crunching is a precursor to the tub cracking eventually (a year? maybe 2 years from now?).

I have seen posts on spraying expanding foam under the tub for support. This will be VERY difficult, because the tile floor is already in place, and we would have to extend the hose somehow to reach the back of the tub. I'm afraid the foam will dampen the insulation that is along the inside of the tub, and I'm worried the foam will also lift the installation pad that is under the bottom of the tub.

What are your thoughts on this? Also, is there a technique that someone has used to lengthen the spray hose on the Great Stuff?

Thank you for any help you could give me.
Old 06-12-14, 09:14 AM
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What is the cause of the crunching sound? Generally a steel tub will not make a crunching sound but as you shift your weight around in the tub it can cause your subfloor and where the tub contacts the walls to make a sound. It could be as simple as dirt or debris between layers of the subfloor or dirt under the tub get ground as the tub or your house flexes.


Foam is sort of "trick" and not so much a proper fix but it can help. You don't have to worry about the foam wetting the insulation as it's foam not water. The difficult part is that because your tub has insulation underneath. For spray foam or better yet, mortar to work it needs to firmly support the bottom of the tub. A layer of squishy insulation on the bottom of the tub can prevent whatever you do underneath from offering much support so it may be a waste of time.

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