What Are the Pros and Cons of Using a Concrete Bathtub?

Marisa O'Connor
Marisa O'Connor
Woman holding a book
Woman holding a book

The pros generally outnumber the cons of using a concrete bathtub. Pro arguments include the material's versatility, allowing a wide gambit of bathtub shapes and sizes, as well as durability and the smooth yet easily gripped surface of concrete. Cons of concrete are that it has a high cost of labor and can crack when exposed to changes in temperature.

Versatility is the primary argument for commissioning or creating a concrete bathtub. Concrete is a very moldable material, so it can be made into just about any shape or size. A concrete tub can be molded in a factory and delivered to where it will be installed, or it can be molded at the site, allowing for larger designs that might not otherwise fit through doors to get to the installation site. Not only is size infinitely adjustable, so is the shape of the tub. Seats, ridges, and any other addition can be included in the design of the tub.

Another argument for using a concrete bathtub is the durability of the material. It's not very likely that a bathtub will be exposed to very much weather, but in the case that it is, concrete is incredibly weatherproof. Concrete is also fireproof, so it is a good material to use when building appliances or furniture. Fire and weather, though rarely, can destroy property, so it's a good idea to use durable materials within the home to minimize devastation when natural or unnatural disasters strike.

An argument that also speaks to the durability of concrete is that it holds up very strongly against compression. This is a good feature to have when there are higher risks of things collapsing on top of the concrete bathtub. Obviously, no one hopes that her roof or a large tree will collapse onto her bathtub, but concrete is one of the few materials that can withstand such high levels of compression. It takes a lot of force to crumble concrete.

Concrete is great for making bathtubs because of the smooth surface it creates when it dries properly. This is somewhat limited to the skill of the person molding and shaping the bathtub, but generally concrete dries to an ideal surface for a bathtub. It is smooth enough to be comfortable when the bather sits inside, but it's also just rough enough to allow the feet to grip the floor and avoid dangerous shower spills.

The main con of using a concrete bathtub is the material's high labor cost. The material itself is relatively inexpensive, which is a pro argument if someone is planning to mold the bathtub on his or her own. Most people, however, prefer to leave that to a professional, and expert concrete craftsmanship does not usually come cheaply. Mainly because of this reason, there are not very many bathtubs made from concrete.

Another argument against using a concrete bathtub is that the material tends to crack from temperature changes. Cracking is caused only by extreme temperature changes, so it won't be affected by normal use. In certain extreme weather climates, this material is not recommended for use because it cannot withstand sudden drops and rises in temperature. Creating the tub can be problematic because concrete has the tendency to crack when cooling and hardening.

How Much Does a Concrete Bathtub Cost?

The cost of a concrete bathtub varies greatly depending on whether it's basic or customized, as well as whether it's an off-the-line model or one created by a luxury designer. On the very low end, you can find concrete bathtubs for about $500, but they won't offer much in the way of aesthetics or customization options. On the high end of the price range, you can expect to pay up to $15,000 for a customized concrete bathtub made by a luxury designer.

Types of Concrete Bathtubs

There are several types of concrete bathtubs that you'll need to consider before installing one in your bathroom. If you want your new tub to be the focal point of a large bathroom, then you might consider a freestanding tub. These types of bathtubs sit in the center of the room, which means they'll need to be finished on all four sides. That does mean a little bit of an extra cost, so factor that into your budget if necessary.

Another option is a sunken tub. These tubs sit inside the floor and give you the opportunity for enhanced plumbing features, such as a whirlpool. Finally, the most common type is the deck tub, which is placed flush against two or three walls. These often can accommodate stairs or seats for extra safety and comfort.

How To Build a Concrete Bathtub

The first step to building a concrete bathtub is deciding where you want it to be in your bathroom. These tubs are heavy, permanent fixtures, as are the pipes and faucets you'll need to have installed, so be sure to think through your plan thoroughly and anticipate any problems with your ideas. It's a good idea (and depending on where you live, possibly a requirement) to have professional plumbers install the pipes and faucets. This helps to ensure there are no expensive or time-consuming setbacks.

Next, it's time to measure. How long do you want your tub to be? Do you want it to be wide and roomy, or would you like a narrower tub to fit into a smaller bathroom? Finally, consider how tall you want it to be. Think about the future as well. If you plan to age in your home, you may want lower sides to make entry and exit easier in the future.

Once you've confirmed and marked your measurements, it's time to create a plywood box to build your concrete bathtub around. Cut plywood boards to your measurements to make the walls of your tub. You do not need to create a plywood bottom. Secure the four walls together with screws. Pour the mix into the plywood mold and wait for it to dry before removing the wooden sides.

Next, create the concrete floor of your tub. Make sure that you create a slope of 1/4 inch per foot of tub that you have. The slope should go toward the drain. Without it, water won't drain from it properly. Finally, install the main drain pipe and faucet. Fill your new concrete bathtub with water and let it sit for 24 hours to ensure there are no leaks.

How To Seal a Concrete Bathtub

The most common technique for sealing a concrete bathtub is to use a penetrating sealer and apply multiple coats of it to the bathtub. Water-based polyurethane is a good example. Some professionals also use epoxy as a primer and then use the polyurethane on top. It's important to note that these items on their own can be a slip-and-fall hazard, though. Adding grit to ensure people have enough traction in the shower is important. 

Benefits of Hiring a Professional for a Concrete Bathtub Installation

Concrete is a heavy material and quite labor-intensive to work with, so it is always a good idea to hire a professional bathroom contractor to help you create the concrete bathtub you are envisioning. There are more benefits than that, though. Bathroom contractors are knowledgeable and experienced in working with plumbing fixtures and a wide variety of materials, which means there is less of a chance that a time- or budget-consuming mistake will happen. Contractors are also licensed and insured, so even if a mistake does happen, you will not likely need to eat any of the costs of it. Finally, hiring a general contractor to complete your bathroom tub install is safer. Working with materials, tools, or pipes that you've never worked with before can be dangerous and may even lead to serious injury.

Can You Build a Concrete Bathtub?

While it may not be a conventional choice of material, you can use concrete to build a bathtub. Depending on your tastes and available space, there are several styles you can choose. You might like soaking, inground, or outdoor tubs.

The major types of concrete tubs include:

  • Freestanding- Freestanding tubs are placed on a floor or against a wall. You can also choose to put it in the middle of a room. Depending on your style and wants, your tub can also have feet.
  • Deck- This kind of tub drops into a deck or has one attached on one or all sides. This deck can be as small or large as you want. 
  • Sunken- Sunken tubs drop down into a hole in the floor. If you need a step-down entrance or want to install a whirlpool, this type of tub is ideal.

If you are building an indoor concrete bathtub, there are some steps you need to take first. First, decide on your tub size and layout. You'll want to be thorough when planning because an inground tub is a relatively permanent fixture. You need to ensure the measurements are correct before pouring.

Next, you'll need to figure out where the plumbing needs to go and roughly install it. In general, if you want to build a concrete bathtub in the shape of a rectangle, you'll need to create a mold out of plywood first. Pour the concrete into the mold and wait for it to dry before removing it. Finally, after everything is dry, you'll need to build the floor and finish hooking up the drain and faucet. Fill the tub with water and let it sit for 24 hours to ensure no leaks are present.

A concrete bathtub is customizable and can suit any style. Concrete is an excellent choice for outdoor tubs because of its durability, so if you are planning an outdoor relaxation area, consider this.

How Much Does a Concrete Bathtub Cost?

A concrete tub is generally affordable and can fit almost anyone's budget. Lower-end styles cost around $500, while more luxurious models cost you up to $15,000. If you want a custom tub, you'll run into a higher price. It can range from $6-10,000. If you choose to build it yourself, you will also have to buy materials to create the concrete bathtub, like plywood, plumbing, concrete materials, and other items. If you want to dye the tub a particular color, you will have to pay for it as well.

Take into account the materials you intend to use and note where you want to install the tub. Also, think about the size and the shape of your tub. A freestanding rectangular tub will be easier to build and less costly than an oval tub.

A round or oval tub requires a more complex mold, which will increase your cost. After you have the basic tub completed, you can choose what faucets and additional fixtures you want, which will create a price difference. You could decide to build a basic tub with plain spouts, or you could choose something more luxurious.

How To Seal a Concrete Bathtub

Concrete is used as a bathtub material because it is sleek and easy to clean. However, concrete is very porous and allows water to soak in if not treated. If you intend to have a concrete bathtub, you need to seal it with a concrete sealer. You generally have two options when choosing a sealer:

  • Penetrating sealer- If you don't want to change the appearance of your tub, a penetrating sealer is best. It is capable of reducing moisture seepage and preventing mold and mildew. You will need to put on three to four coats of the material for the best results. After letting it cure for 24 hours, your tub will be ready for use. A benefit of a penetrating sealer is the natural finish left behind, which ensures your tub is not slippery.
  • Concrete coating- A concrete tub coating is best if you would like a decorative sheen for your tub or if you want to change the tub color. A concrete coating will not peel or yellow and keeps moisture and mold from accumulating. It may be slippery, so you can add a material to make the tub matte, reduce slippage, and increase traction.

The price and features of sealants vary. You can choose a basic, clear one or one that leaves a silky or enameled finish. When sealing, you will need to apply several thin coats of whichever one you choose.

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Discussion Comments

Phaedrus

I have a concrete bathtub in my house and I think it's great. I had a few plastic tubs crack on my over the years, and sometimes a cast iron tub will start to flake off bits of the porcelain coating. The concrete tub is way too thick to crack, and it's not as slick as a porcelain bathtub. That's important for me, since I'm getting up in age and I'm always afraid I'm going to fall and break a hip.

The only problem I've had is keeping the tub from developing mold in the crevices. I keep a can of anti-fungal bathroom spray near the tub and I give the tub a few squirts after I bathe. A concrete tub isn't as easy to keep clean as a smoother porcelain tub, but acrylic tubs can have the same problem, too.

mrwormy

When we renovated our house last year, the designer came up with a way to enlarge our downstairs bathroom by taking out a wall. I always thought the cast iron bathtub was too small, so we started discussing alternatives. She brought up the idea of a concrete bathtub, since it could be custom-made on site to whatever size I wanted. The size of the bathroom door wouldn't matter.

I seriously considered it, but then the cost of all that customized work proved to be too much. I went with a more conventional porcelain tub and they put it in the bathroom while the wall was still down.

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