Tub flex

[GaetanoL]

I recently had a Hydrosystems fiberglass tub installed by a contractor. He grouted where the tub meets the wall tiles (3 sides). That seal between the tub and the tiles was fine until we took our first bath. At that point the tub must have flexed slightly and the seal cracked. I was going to have the contractor remove the grout and use 100% silicone at that interface. When I spoke to a rep with the tub manufacturer, he said a properly installed tub should not drop at all when filled with water. Is that correct? The gap between the tub and last row of tiles increase on the order of a millimeter, maybe a little less. Is that to be expected when the tub is filled?

[Tool Guy - Kg]

Hi Guy,

The joint you speak of is notorious for movement due to: 1) the fact that there are differential materials meeting at the joint, 2) it's a change of planes there, and 3) the fact that the tub is filled with much heavy water that stresses the joint. That joint really should have been caulked with a sealant like 100% silicone. The grout needs to be removed before the sealant is installed.

But the application of sealant alone doesn't guarantee that the tub was installed correctly. Many tub installation instructions require support such as foam, mortar, or other approved material under the belly of the tub. Refer to the instructions for their requirements. Then you'll need to speak to the contractor or view through the drain assembly hole in the floor (or access panel, if one exists) for evidence of what, if anything, is under there.

[Houston Remodeler]

What Bubba said plus;

You can get grout matching silicone in sanded, unsanded, shiny and matte from our buds at www.ColorRiteInc.com Tell them we sent you.

[Davy]

Does the the tub have a lip for the tile to go over? You make it sound as if the tub was installed against the tile walls. The tub is usually set against the studs and then the tile installed down over the tub lip. Is that how this was done?