How to Install a Bathtub on a Concrete Floor

How to Install a Bathtub on a Concrete Floor

Are you getting ready to remodel your bathroom or install a new bathtub in a basement bathroom? A new bathtub can really liven up the place. 

Depending on the features, it can also add much-wanted luxury to your decor! But if you’re working on a cement or concrete floor, this DIY project will need special consideration.

It is possible to install a bathtub on a concrete floor without the help of a professional. But you want to be confident that you know what you’re doing beforehand.

When in doubt, ask for help. That way, you’ll be sure to avoid damaging your tub or your bathroom itself.

Here’s everything you need to know about the installation process.

Tools and Supplies You Will Need

The majority of homeowners select an alcove or acrylic bathtub when they do a bathroom remodel. These types of tubs are inexpensive while still being durable enough to last for years.

Because the installation process is simple, they’re ideal for people who want to DIY the process.

Before you get started, you’ll want to make sure that you have all of the relevant supplies:

  •    Waterproof sealing material that’s safe for use on the walls
  •    Rag and soap for cleaning the walls 
  •    Floor coating to even the floor level
  •    Notched trowel for applying the floor coating
  •    2″ by 4″ wood piece for placing the tub
  •    Rubber mallet for tapping the wood 
  •    Drywall screws and wall studs for installation

If you’re also looking to install the drain at the same time, you’ll need components including:

  •    A threading pipe for the tub
  •    Linkage, plunger , and overflow rod for the tub
  •    A spout pipe (if you don’t have a pre-installed copper pipe)
  •    Pliers to fasten and unfasten the existing plumbing

The actual drain installation process is relatively straightforward. You’ll take steps to make it easy to hook the existing plumbing into the bathtub drain.

8 Steps to Install a Bathtub on a Concrete Floor

Step 1. Secure your spray area

The “spray area” refers to any part of the wall and floor that might be splashed with water when you use the tub. That means the area directly surrounding the tub itself.

Whether you’re working on bare concrete or a tile floor, you need to make sure that this area is waterproof. Otherwise, you could end up dealing with mildew.

You’ll need to pick up a waterproof sealant at the hardware or plumbing store. Before you set the sealant on the walls, use a rag and soap to clean them thoroughly.

If there’s dirt or dust on the surface, the sealant won’t be able to adhere properly. It might peel off or be ineffective.

Step 2. Level your floor

If you’re lucky, you won’t have to do anything special to your floor. But it’s common for concrete flooring to be uneven.

When you install a bathtub, the floor below must be even to get the correct balance. Uneven balancing can also warp and damage a fiberglass bathtub.

Inspect your floor. Are there uneven spaces? Where?

Your next step will be to coat the concrete slab in the waterproof sealant or caulk. You should use multiple layers of this substance until you have an even surface, using your notched trowel for guidance.

Wait for the sealant to dry completely before you continue.

Step 3. Place your bathtub

This might sound like the easiest step, but it actually requires enormous care and patience. You’ll put the bathtub exactly where it is supposed to sit.

To make life easier, you should place the tub wherever you already have drain plumbing. Do your best to line the tub drain hole up with the existing spout plumbing.

You might want to work with a partner. It’s important that you’re gentle when setting the tub down, as being too rough might cause the surface of the floor or the drain itself to become damaged.

Step 4. Level your bathtub

Next, you’ll worry about the leveling process. You want to make sure that each corner of the bathtub has an even placement on the floor.

This is where your rubber mallet and 2×4″ come into play. You’ll wedge the wood against the tub and tap it until it reaches the proper area. Be sure that the bottom of the tub is in the right spot against the sealant.

Step 5. Screw the bathtub in

Your bathtub model should have come with screws for the installation process. You’ll drill these into the drywall and secure the bathtub flange to the wall.

The manual will likely have instructions for how to do this. As a general rule, you should have one screw along every six inches of tub flange. Tighten them as needed.

Step 6. Insert the drain

Now you have the bathtub lined up with your existing drain pipe. It’s time to take the threading pipe and insert it securely into the male type of thread until you reach the bottom of the drain.

Since you’re using your existing plumbing, this step should be relatively simple.

Step 7. Install the remaining components

Other parts of the bathtub will need to be hooked up to the plumbing. These include the overflow rod, linkage, and plunger .

Make sure you install them correctly with the overflow hole so that the bathtub can drain excess water. Then tighten the contraption using screws.

Step 8. Thread the spout

This final step is super simple. You’ll just take your spout pipe, insert it into the hole, and fasten it with pliers. Some models may already have their spout installed, rendering this step unnecessary.


Installing a bathtub on a concrete floor doesn’t have to be difficult. You mainly want to ensure that the floor is even and that the bathtub model is placed properly. As long as you use the correct tools and take care of your work, you shouldn’t run into any issues.

Installing the drain and plumbing should be similarly simple. It’s best to line up the tub with the existing plumbing, so you don’t need to re-thread any of the pipes.