How to install a bathtub video

Removing a bathtub and installing a new one is an approachable task for many. If you carefully prepare and work with a helper, you can complete this DIY project in one day.

Securing the tub

With a notched trowel, spread a 2-inch layer of mortar on the subfloor where the tub will sit. Lift the tub in place and position it so that it’s tight against the walls. Hold a carpenter’s level on the tub and check that it’s level. If not, adjust it by placing wood shims under the tub.

If the tub is on the floor, not needed. If it’s stiff enough, not needed. Sometimes mortar is used when there is flex. Most deck mounted tubs need some sort of support.

One of the features common to most slab-on-grade homes is the bath trap. Bath traps, a type of “slab leave-out”, are located under bathtubs. Why leave a big hole under a bath tub? Generally these openings are left for the convenience of plumbing contractors in case the plumbing needs to be moved or serviced.

Don’t Tile Under A Drop-In Or Alcove Tub

If the front of your tub is exposed, you can tile underneath it about an inch. This can complete the look of your floor and allow the tub to rest on the subfloor. It can also make the job of replacing your tiles easier later on.

Bathroom floors are notorious for suffering water damage and the area under the bathtub is no exception. Flooring repairs can be intimidating, but the subfloor under the tub generally consists of plywood secured over floor joists and is fairly simple to replace — once you get access to it.

It mostly doesn’t matter. The only reason to do it is if the original floor is weak and needs reinforcement. I would probably do it so the tub has a nice flat surface to sit on. There is really no reason not to do it other than it might cost you one more sheet of ply.

There’s no real reason to have the cement backer board under the typical tub. I usually just run it under the front edge a couple or three inches so the tub is resting on it, and the rest of the tub is supported by the wood blocking attached to the studs.

Plywood as a Subfloor Material

Traditionally, exterior grade plywood has been the subfloor material of choice for many bathroom flooring projects. Plywood is made by gluing alternating layers of wood veneer. CDX plywood (¾”) in particular is used often because it has a high level of resistance to moisture and humidity.

If you already have sheet laminate in your bathroom you should be in good shape. You can lay your vinyl plank flooring right on top of it. Just make sure it’s flat and not peeling up anywhere. You‘ll still want to add 100% silicone caulk in front of the bathtub which I go into next.

A floating floor needs to float, do not put it under the shower pan. You will need to leave an expansion gap at the pan per manufacturer recommendations on whatever floor you choose. Therefore, you need not be perfect with the install, but will cover the edge with molding.

They aren’t as easy to cut into rounded shapes as vinyl tile is, so they often require that you remove the toilet. It’s better to leave the toilet where it is and work around it if you can.

If you’re putting down domestic vinyl, then underlay is not needed. You will need to put down some plywood ideally 6mm, then the vinyl. I wouldn’t recommend putting vinyl on top of floorboards direct because in time you will get problems.

Engineered vinyl planks and tiles are a great choice for the bathroom. Vinyl planks with a waterproof core such as WPC or SPC vinyl are designed specifically to prevent water damage while making your bathroom look beautiful.

Vinyl flooring is usually not installed directly over the subfloor in residential applications. In most cases 4-by-8-foot sheets of particle board or plywood must be installed in preparation for the vinyl floor install. It needs to be built up to the same elevation of the other flooring types in the house.