How To Install a Bathtub on Concrete Floor: A Step-by-Step Guide

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Installing a bathtub on a concrete or cement floor can be a daunting task. There are many potential pitfalls that can occur, and if not done properly, the results can be disastrous.

It’s not impossible to install a bathtub on a concrete floor by yourself. However, you will need the know-how before you begin so that you can organize the installation.

In this article, we will walk you through the process step-by-step and show you how to avoid the most common mistakes. We’ll also provide some tips for installing a bathtub on a concrete floor in cases where it is impossible to avoid them.

Tools and Materials Needed

When remodeling a bathroom, most people decide on an alcove bathtub because they are relatively easy to install and can be personalized in many ways.

There are some tools and supplies you will need to gather before starting this DIY project to make sure everything goes smoothly:

Bathtub Installation

Gorilla Waterproof Caulk & Seal100% Silicone Sealant, 2.8oz Squeeze Tube, Clear (Pack of 2)

Waterproof sealant for walls

Spongeables Exfoliating Body Wash In A Sponge, Sea Salt, Contains Avocado Oil and Vitamin E, Cleanse, Exfoliate and Moisturize, 3.5 Ounce (Pack of 3)

Sponge and soapy water

Ardex Feather Finish Grey/Gray/Gris Self-Drying Cement Based Bag 10 Lbs

Floor leveling using mortar

Fiskars 384220-1001 Ergo Garden Hand Trowel, Black


Self-Drilling E-z Anchor Toggle Kit, Heavy Duty Drywall Toggle Ancor with Fitting Metal Zinc Phillip Screws #8 x 2-1/4 - Holds Up to 100 Lb. (5 Pack)

Screws and wall studs for the drywall

Installing A Drain

If you are installing a new drain to your bathtub, the tools and supplies for this are as follows:

  • Threading pipe
  • A spout pipe
  • Overflow rod, a plunger, and the linkage
  • A pair of adjustable pliers

10 Simple Steps On How To Install A Bathtub On A Concrete Floor

Interior of modern bathroom with white walls

Step 1. Seal It

Ensure that the walls and surfaces around the bathtub are treated with a waterproof sealant to avoid any chance of mold or mildew growing. Tiled surfaces will need to be washed with soapy water first and dried for the sealant to be effective.

Step 2. Level The Floor

If this is a replacement bathtub, then you should already have a relatively level floor. However, a new install will most probably need to be leveled using an epoxy compound. Leave the compound to dry for at least 12 hours.

Step 3. Marking And Measuring

Once you know exactly where your bathtub will be positioned, you can mark it on the floor so that you can drill the holes to be able to anchor the bathtub to the floor.

Step 4. Anchors Away

Affix the anchors to the bathtub with an electric drill or a screwdriver. Drill the holes in the floor for the bolts in order to hold the bathtub in place.

Step 5. Install The Bathtub

It is very easy to damage the bathtub or the drain pout when placing the bathtub in its position, so be very careful. Place the bathtub on the joist and secure the anchors that are attached to the bathtub to the concrete floor using bolts.

Next, attach the bathtub flange to the wall using the screws that came with the bathtub.

Step 6. Drainage Installation

Carefully align the bathtub drain over the drainpipe opening. Insert the threading pipe through the male side all the way to the base of the drain.

Step 7. Installing The Overflow

Install the overflow rod, plunger, and linkage within the overflow hole of your bathtub while making sure it is level with the overflow drain hole.

Step 8. Spout Pipe Installation

Take your new spout pipe and ease it down the spout hole until it reaches the wall, and then secure it using a set of pliers. Typically, if you have copper piping, then that part has already been done for you.

Step 9. Silicone

This is the final step before you can jump in the bathtub and have the nice luxurious bath that you deserve. To prevent any water damage to the floorboards or to stop any insects from coming through, it is a good idea to silicone or caulk around the tub, sealing off any gaps.

Let it dry for at least 12 hours to get the best seal.

Step 10. Examining The Project

When everything is attached and is in place, slowly fill up the bathtub making sure there are no leaks in the drain and the stopper is creating a seal.

Listen out for any noises or movement once the bathtub is full, and then check that the overflow is working correctly and excess water is draining through.

FAQS Frequently Asked Questions

How long does it take to install a bathtub?

There are a lot of factors that will determine how long it will exactly take. But if you have the bathtub and the drainage is in place, then typically, it can take 2 to 3 days because of the waiting time in between for drying and certain things to set before you can move on to the next part.

How do you reinforce a bathtub floor?

The best way to reinforce the floor under a bathtub is double down on the joists. Ensure that you have left enough space for the plumbing pipes.

How heavy is a full bathtub?

Depending on the type of bathtub you have, it could range anywhere from 75 pounds for an acrylic bathtub to anything up to 400 pounds for a cast iron one. Taking into consideration the weight of the bathtub, the water, and the person bathing, the weight can exceed 1200 pounds.

What causes fiberglass bathtubs to crack?

Improper support will cause the bathtub to flex and move and eventually warp and start to crack. Dropping objects in the bathtub can cause small divots and chips, which can, in time, become cracks.

Is installing a bathtub difficult?

It depends on whether you are attempting to install a new bathtub in the bathroom or replace an existing bathtub. The latter is far simpler as the support, drain system, and tiling are already present. The biggest job, in this case, would be the disposal of the existing bathtub.

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