Bathroom Facelift: How to Install a Bathtub

Nobody wants a moldy old bathtub, so here’s a step-by-step guide on how to install a new one.

Bathtubs are the focal point of any bathroom, and they can make or break the entire room’s look. Regardless, it’s important to install them correctly to avoid built-up moisture and keep things looking neat. You definitely don’t want to cut corners here because you’ll end up with a shoddy result.

Also, wear protective gear and remember that this process will require a lot of careful calculations and some physical strength. Ready? Let’s get started installing that tub.

What Are Your Options?

Before getting to the installation, have you purchased your new bathtub yet? If not, keep in mind that some materials are more durable than others. Also, some are good purely for their appearance.

Here are the most common materials used:

  • Porcelain on Steel (PoS): These are generally easy to install and are going to be one of the least expensive options. They’re made of solid steel and then coated with porcelain.
  • Fiberglass: Fiberglass is also an inexpensive option. They’re super light, which can make installation easy, but the finish will fade over time.
  • Acrylic: These are made from heated acrylic that gets pulled over a mold. The acrylic gets vacuumed tightly and then reinforced with fiberglass and resin. They’re easy to clean and generally pretty durable; however, there may be thin spots near the edge from the acrylic being pulled too tight.
  • Cast Iron: Cast iron tubs are among the heaviest options, so it’s probably best to hire a professional to do the installation for you. These are nice if you’re looking for a standard tub, but if you want to add extra features, you’ll want to choose a different material.
  • Americast: This material was made by American Standard and is a lighter alternative to cast iron. Despite weighing significantly less, it still offers the durability and heat retention of a cast iron tub (1).
  • Cultured Marble: Marble is typically the most expensive of these materials. It’s also the most challenging to install and hardest to maintain, but it’s excellent for anybody looking for a high-end look.
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How to Remove an Old Bathtub

For those of you replacing an old bathtub, it’s important to follow careful instructions to remove the old unit:

  1. Turn the water off: Turn the water to your home off to avoid a mess. Once the water is switched off, turn the bathtub faucet on to make sure the lines are completely drained.
  2. Remove the connections: Use a screwdriver to remove the faucet. You should then use your tools to remove the handles, overflow drain cover, and the drain cover at the bottom of your unit. Keep in mind there may be plastic coverings over the screws that will need prying off. If you’re looking to save a couple of bucks, you may be able to reuse your faucet and other pieces so be mindful when removing.
  3. Remove the surround: After all the extra pieces are removed, you can go ahead and start removing the surrounding area of your tub. For some, this may be a tub surround, and for others, it may be tiles. This may not seem like a necessary step, but you’ll need the wall studs to be exposed in order to install your new unit.
  4. Locate the plumbing: At this point, you need to access to your plumbing. Depending on the way your house is built, your pipes will be accessible from the room next to the bathroom. Alternatively, they may be right in the floor underneath where your old bathtub was. Don’t be surprised if you need to cut a hole in the wall or floor to do this.
  5. Remove the tub: Finally, you can remove the old bathtub. Unscrew the drain and overflow, then remove your unit. If the tub is made of acrylic or fiberglass, you can cut it into pieces with a jigsaw to make it easier to take out.

Quick Tip

If you have a tub surround, you can use a utility knife along the outer drywall to cut through and then use a pry bar to pry the surround forward. Be mindful of any possible pipe or wire locations. It’s easiest to work from top to bottom for this step.

How to Install a Bathtub

Once you’ve chosen the bathtub you want, your next step is to install it. To get the job done correctly, make sure you have access to the following tools:

  • Screwdriver.
  • Wrench.
  • Pry bar.
  • Utility knife.
  • Jigsaw.
  • Measuring tape.
  • 2 x 4 wooden board.
  • A Level.
  • Caulk.

Each type of tub will have a varied installation process. Generally, the process is going to be similar all around. However, there are some things you need to keep in mind with some styles in particular.

How to Install an Acrylic Bathtub

Most acrylic tubs will come in a standard size, but it’s important to take careful measurements. Once you’re sure of your measurements, follow these steps:

  1. Inspect your floor for damage: Before installing a new tub, make sure the floor where your old tub was isn’t damaged. If it is, fix that issue before installing your tub.
  2. Properly fit your tub supports: An acrylic tub requires supports to be in place to help the water run to the drain. The supports on the faucet end should be shorter than those opposite of it. This will ensure the water properly runs toward the drain area.
  3. Sort out your plumbing: It’s recommended not to fit your pipes close together. Pipes too close together can make future repairs more difficult.
  4. Install your siding: Siding is required with acrylic tubs to help prevent leakage. The siding should be fitted to the lip of the tub to prevent water damage to your floors.
  5. Apply sealant: Once everything is in place, secure the tub with sealant. Sealant should be applied along the bath and the wall as well as every edge. You should let the sealant dry for 24 hours before using your new tub.

How to Install a Fiberglass Bathtub

To install a fiberglass tub, follow these instructions:

  1. Install a ledger board: This will support the back of your tub while keeping it level.
  2. Check all plumbing and replace shower valve: While you have your walls open, it’s smart to check your plumbing and replace any parts that need it. This will help prevent any leaks from your pipes.
  3. Install your overflow pipe: Attach the pipe to your tub before setting the unit down. Use putty around your strand piece to prevent leakage and keep it in place. Place your gasket on the other side and spin the drain until secure.
  4. Install your stopper: This will plug your drain. Feed it through the pipe and then screw the topper in place.
  5. Install the entire unit: Fit your tub into its designated area and make sure everything fits. Screw everything into place once the tub has been set.

How to Install a Steel, Cast Iron or Marble Bathtub

Steel, cast iron and marble tubs are installed in virtually the same manner. However, you need to keep in mind that marble is significantly heavier than the other two, so getting a friend’s help may be necessary.

  1. Dry-fit your tub to make sure it fits: You should also double-check to make sure all drain holes line up, so everything is even.
  2. Install support: If the tub will be backed up against a wall, make sure there is support in place to hold the weight.
  3. Attach your drain: Before placing the tub, attach your drain to it for easier installation. Use plumbers putty on the bottom of the filter to keep it in place.
  4. Connect your overflow drain: Feed the trip lever stopper through the drain and use a screwdriver to secure the cover to the inside of the tub.
  5. Secure the tub in place: Finally, secure your tub in place with a bathtub caulk and high-quality sealant.

How to Install a Bathtub Surround

Sometimes, a tub surround can help bring up a look for your bathroom. If you’re interested in installing a surround, it’s a relatively straightforward process:

  1. Remove fixtures and clean: Any dirt or other impurities can cause an uneven end result. Not to mention, cleaning these areas will improve the water quality too. Clean the entire area since you may not get the chance to do it again soon.
  2. Create a template: The idea here is to make sure you know the location of each hole and fitting area. This will give you a good idea of what everything should look like and their exact locations and dimensions. You can make this draft on a piece of cardboard.
  3. Transfer your markings: Any markings you made on your template should be transferred to the area where you’re installing your tub. Then, you can cut out any holes you need.
  4. Dry-fit your panels: This will help ensure that everything has been measured and cut correctly.
  5. Attach your unit to the wall: To do this, use a strong tub surround adhesive. Press firmly on each panel to make sure it’s secure.
  6. Replace all fixtures: At this point, you should either put your old fixtures back into place or install your new fixtures.
  7. Check for leaks: Caulk any joints to prevent leaks. Let the adhesive set for however long the manufacturer recommends before using your tub/shower. This will ensure the adhesive dries properly and stays sticky.

Make Sure

The adhesive should be applied as a continuous line to ensure a secure fit.

Give Your Bathroom a Facelift

The look of your tub will make or break the entire look of your bathroom. Nobody wants to see a mold-ridden bathtub let alone get in one. Mold is an unfortunate side effect that can stem from a shoddy DIY job, so if you want to do it yourself, make sure you install it correctly.

Always make sure your measurements are correct and use the right tools to get the job done. Finally, remember that with projects like these, it’s best to take your time.

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.