How to Fix a Bathtub That Squeaks

Inspect the area under the bathtub with a flashlight. You may need to cut through the drywall in an adjacent stairway, closet wall or room to access the area underneath or use an access panel.

Locate any loose foam molding along the tub’s base once you have accessed the squeaking area underneath the bathtub. Reattach any loose foam molding to the base of the tub with construction adhesive. Press the molding against the tub to establish a good bond and adhere to the surface.

Look for the mortar bed or concrete pad under the tub. If you do not see the bed but find a sheet of plywood instead, you have to fit the mortar around the tub. Spray the surface around the drain hole with expanding foam to prevent mortar from dripping onto the floor.

Prepare quick-set concrete in a 5-gallon plastic bucket, according to the manufacturer’s directions, with a trowel until it achieves a workable consistency. Pack the mortar onto the plywood sheet underneath the tub with the trowel.

Allow the mortar to self-level and set, preferably to a thickness of 1/2- to 3/4-inch or until it touches the base of the bathtub. However, always defer to the manufacturer’s instructions for your specific type of tub. For instance, Kohler requires a 2-inch-thick bed of concrete or mortar for its drop-in bathtub.

Install a 2-by-4 piece of lumber at the access panel or opening at the base of the tub to contain the mortar while it cures and keep it from seeping out.

Wait for the mortar to cure for the time specified on the label’s directions, typically one to two days. Remove the 2-by-4 once the mortar bed cures then close the access panel. If you removed drywall, reinstall it in the hole with drywall compound.