How to Make the Bed for My Drop-In Tub

Determine the desired location for your drop-in tub in your bathroom. Measure the width and height of the drop-in tub from the bottom edge to the lip, or flange, with a tape measure.

Use the existing frame for the bed if your new drop-in tub matches the dimensions of the existing tub. If the dimensions differ, use a sledgehammer to knock down the old frame then discard the old wood pieces or reuse them if they can be cut to the needed measurements.

Copy the new tub's height measurements onto the wood beams, which should each be 2 inches thicker than the base height of your drop-in tub. Cut the beams, as needed, with a circular saw.

Place your drop-in tub in the desired position in your bathroom. Outline the tub with a chalk line. Remove the tub and place the wood beams so that they rest against the inside of the chalk lines. Attach the wood beams together with wood glue. Drill holes for the plumbing and install the fixtures.

Mix casting plaster or cement, according to the manufacturer’s instructions, in a bucket. Pour the cement or plaster into the bottom of the frame to form a 2-inch layer. Smooth out the bed with the back of a trowel. Position the tub onto the wet cement or plaster and press down to secure it in place. Check that the tub is even with a level. Allow the plaster or cement bed to dry according to the manufacturer’s recommended time.