How to install a bathtub - A Complete Bathtub Replacement Guide

Posted by Bath1 ,Dec 17th 2024

Revamping a bathroom is an excellent investment for those who can flaunt money. But for those who are on a tight budget can refresh the bathroom style with a simple bathtub replacement. Adding a bathtub can create a luxurious spa ambiance for your bathroom.

Installing a new bathtub is complicated and time-consuming. It is best to seek professional help to do the job, but it could cost you a fortune. For those not willing to splurge money can refer to our detailed step by step guide on bathtub installation.

Before we get right into installing a bathtub, it is good to have an overview of all the types of units available in the market. Our easy-to-read guide will also provide the best buying tips when selecting your next tub.

Types of Bathtubs

Bathtubs come in an array of choices segregated by material and style. Let us first look at the different materials used to make the bathtubs.

Acrylic

Acrylic is the most common material used to make bathtubs due to the ability to its lightweight and easy to install feature. Acrylic is innately soft; hence, manufacturers often use fiberglass to toughen vacuum-formed sheets of acrylic to increase durability. Acrylic tubs are available in a variety of shapes and styles, making it one of the most chosen amongst buyers.

It is best for prominent families that share bathroom because by nature acrylic material is more resistant to corrosion and fading. Acrylic is also very easy to clean and maintain. Acrylic units costs between $300 to $1000.

Fiberglass

A fiberglass is an economical option for bathtubs. They are lightweight, modern, and versatile, but they do not make the best tubs for soaking. Fiberglass is porous and does not retain heat; hence they are more suitable for quick baths. Often they are coated with acrylic to give added shine and make it easy to clean. It requires careful cleaning, and one must avoid the use of abrasive cleaners. Fiberglass units do not cost much, and the price range starts at $200 with a maximum price being no more than $800.

Fiberglass bathtubs are inexpensive but at the same time, short lasting. If durability is your primary concern, avoid fiberglass tubs as they are less resistance to crack, scratch, and corrosion. They even tend to fade away quickly.

Cast Iron

A complete opposite of fiberglass, cast iron bathtubs are heavy, durable and retains heat. The vintage style bathtub is the perfect choice for those who enjoy long soaks. While other materials of bathtub offer a variety of colors and styles, cast iron comes in limited style. Moreover, cast iron is heavy as a dump truck and requires additional support of flooring.

Cast iron units fall in the same price range as curated marble bathtubs, at least the high-end ones. They are best for anyone looking to give traditional elegance to their timeless bathrooms. Cast iron bathtub has a wide price stretch, ranging from $300 to $2000.

Steel

The steel bathtub is an economically feasible option for those who do not want to spend a lot. These units weigh lesser than the cast iron bathtubs but do not give the same vintage look. Another downside of the steel bathtubs is that it is noisy at the time of filling the tub. In comparison to other materials, steel bathtubs have the lowest sell ratio. These units cost anywhere between $200 to $800

Cultured Marble

Cultured marble tubs can draw in more attention than other material, due to its availability in a wide range of beautiful colors and natural looking patterns. While they come at a higher price than the rest, it can uplift the overall style and feel of the bathroom.

Marble differs from the rest of the materials as it provides a unique and vibrant appearance. However, cultured marble bathtub is heavy and more expensive to maintain. Polished marble is a cast product, hence allows buyers to customize according to their needs. Moreso, it is highly durable due to its robust material. These units can cost anywhere between $1500 to $3000.

Styles of Bathtub

As mentioned earlier, bathtubs do come in various styles, and it is best to choose what fits your requirements best. Among the most common styles include the alcove, walk-in tubs, soaking tub and whirlpool and air tubs. Alcove is the most common style and is best for younger generations.

Meanwhile, soaking tubs are hollow than others and allow one to immerse their body entirely. However, if one’s priority is to create a spa-like environment than whirlpool and air tubs are the best option. They are equipped with jets of water around the tub that shoot water into the tub to massage and relax different parts of the body.

Let’s begin the process

It's time to get your hands wet and dirty. First and foremost one has to remove the old tub and then install a new one. Our easy-to-understand guide breaks down the whole process into three sections - Removing the old bathtub, choosing the right tub, and installing the new one.

Remove old bathtub

One must know that removing and installing a bathtub is a tedious and labor-intensive task. At first, it may seem an arduous job, but our easy-to-understand guide will break it down into simple steps. Follow the below steps to remove the existing tub.

Required Tools

Utility knife
Pliers
Pry bar
Hammer
Screwdriver
Reciprocating saw
Crowbar
2x4s
Strainer wrench
Personal protective equipment (gloves, eye protection)

Prep the space

It is crucial to first measure the tub, bathroom fixtures, and space between the door. The measurement will provide a mindmap of how you will get the tub out the door. It will also let us know if any of the bathroom fixtures such as sink or toilet will be in the way at the time of removing the tub. In that case, remove the sink and the toilet and also cover the floor with plywood to avoid any damage.

Shutting down water

First and foremost, shut off the water supply. Turn off the water cutoff valve in the bathroom. If there isn’t a separate valve for the bathroom, then close water supply for the entire house. Next, turn on the tap at a lower ground level part of your home to remove pressure in the lines.

Disconnect Drain

Take the screwdriver to detach the overflow cover plate. Next, remove the drain assembly attached to it and unfasten the mounting bracket. Next, you need to disconnect the drain and remove the strainer. Remove the drain flange using proper tools such as strainer wrench.

Detach Waste-and-Overflow

Open the access panel where the waste-and-overflow (WO) unit is placed. In most cases, it is either behind the tub or below it. Using pliers disconnect the WO from the drain line where the overflow valve and drain intersect. All fittings are not designed the same, so there may be variation. In case, the accessory is galvanized steel, then use lubricants to loosen the joints. If they are cemented plastic, then you will have to cut through a pipe. If the new tub will fit the existing WO unit, then there is no need to remove it from the bathtub.

Remove Tub Spout and Tiles

Remove the tub surround to expose the nails and screws attached to it. All tubs are not fastened in the same manner, so there may be variation. It is recommended to remove the wall surface about eight inches high. Leave the faucet handles as it is. In case, if the faucet handle is within the eight inches of height, then remove it with the help of screwdrivers.

Next, use drywall saw to cut through the drywall. Also, take a flat pry bar to remove the tiles. Doing so will expose all screws and nails fastening the tub. Use tools to unscrew any bolts anchoring the tub. Now, using the pry bar pull the tub an inch from the back wall.

If the tub is an old fashioned tub, it will be difficult to slide the tub out. In that case, lift the tub from one corner and pull it out using a crowbar and 2x4s. Call in some muscle power (could be a friend or family member) to lift the tub upright and guide it out of the bathroom.

Disposing of the tub

One must know if the tub is recyclable or not. If so, dispose of it properly at recycling workshop.

Choosing the right bathtub

It is best to first measure the approximate length and width of the old tub. Generally, most bathtubs are 5ft long and about 2.5 feet wide once you have all measurements in place begun your hunting process for a new bathtub.

There are various aspects to consider before purchasing a tub. Of the many elements, buyers must first find pricing, comfort, availability of space, and overall bathroom style. Buyers must choose a unit that blends in with bathroom style or enhances the ambiance.

Comfort

Before making any purchase, it is recommended to sit in the bathtub and try the size to see if it offers the right comfort. Next, see if the tub is compatible with your body frame. At this point, one must also consider the placement of bath fixtures and accessibility of showers. When it comes to comfort, Kohler tubs offer unparalleled tranquillity.

Electrical concerns

In case you plan to go for air-jet tubs then take into account the building code requirements as they vary based on location. Also, it is essential to place the tub following the electrical panel. Some air-jet tubs demand independent circuits; in that case, the entire panel will need to be upgraded.

Aesthetics

Before purchasing a tub, one must consider matching the overall style of the bathroom. A bathtub must be such that it enhances the ambiance. The tub surround or tiles must also complement other elements of the bathroom. A unique tub design is a great way to translate your style.

Water heater requirements

When purchasing a new tub, it is imperative to know the water heater requirements. If you have a small budget than choose a tub that demands similar heating capacity to the old tub. In case it requires additional heating then you will have to install a second water heater that can cost anywhere between $600 to $1000. The basic rule is that the water tank must be ⅔ times that size of the bathtub. It's best to figure it out to avoid taking cold baths.

Structural support

In case you are installing your first bathtub, then one must calculate if the flooring will be able to take the capacity of the bathtub, water weight and the weight of a body. One must reinforce the flooring before making the purchase.

Buyers also have to choose from two of the most common built-in bathtubs - Alcove and drop-in. A drop-in tub can be placed anywhere and does not have to be placed around a wall. Meanwhile, an alcove setting tub must be enclosed by walls on three sides. The open side in the alcove setting will have the shower. Moreover, a drop-in tub can be placed on a platform or floor. It also conceals plumbing, so there is nothing unfancy on display.

Also, drop-in tubs are best for long soaks and offer more comfort than an alcove. The alcove tub is best for those that find it difficult to get in and out of the bathtub. Hence, in an alcove setting one can always install a safety grab bar to assist in entering or exiting the tub. Meanwhile, a drop-in tub is easy to get in but difficult to get out.

Installing the new bathtub

Almost fifty percent of the work is complete once you have removed the old tub and chose the new one. The only remaining task is to install your new bathtub. The below step-by-step instructions will make the bathtub installation easy as pie.

Prep work for new installation

Measure the space before purchasing to see if the tub will fit properly. In case the new tub is not of a different size or orientation, then the plumbing will need minor relocating. Ensure the subfloor is in level and if not, then even it using the leveling compound. Clear the space of any debris and unwanted materials lying around.

Required materials

New tub
Level
Adhesive
Drain shoe and gasket
2x4s
Waste-and-overflow unit (in case it needs to be changed)
Apply Grout
Screwdriver
Tiles
Measuring tape
Strainer wrench
Ledger boards
Drill
Silicone or tub-and-tile caulk
Plumber's putty
Screws
Overflow trim and flange
Shoe tube
Plastic putty knife
Cement board

Installing a new bathtub unit

Installing a bathtub might feel complicated, but with this Do It Yourself (DIY) it will be easy tackling. However, one must keep the contact information of a plumber handy in case you can not see the project through.

Inspecting the drain

First, check the drain and inspect for any damaged plumbing. Replace any damaged parts and ensure that the drain is placed in the right location. Install the existing waste-and-overflow unit. Measure the height of the flange and mark it on the wall. Now, screw the ledger board to the stud in the wall so that it is rightly placed below the flange. Attaching the ledger board is crucial as it holds the weight of the tub.

Dry fit tubes and overflow trim

Once the ledger board is crewed, dry-fit the overflow tube and shoe. Recheck the connections and make them permanent. Position the gasket on the overflow flange as it provides the seal around the pipe. Using the screwdriver, insert the screw, and secure the overflow trim. The overflow drain will stop the tub from overflowing by directing water to the drain pipe.

Now place the shoe tube in overflow tube and on the other end into the drain. Now secure the drain by wrapping the bottom with plumbers putty. Tap it into the tub from inside to make it robust. Now insert the gasket around the strainer and fasten it to the drain chute using strainer wrench. Clear the drain of any debris and remove excess putty using a plastic putty knife.

Placing the bathtub

Before sliding the new bathtub to its position, ensure that the plumbing connections are perfect. It is best first to plan the move in the head and then do it so that you avoid any damage to the plumbing unit. To make it easier, place the tub on 2x4s while moving it. Call a friend or family member to help move the tub into its position. Get the helper to set the overflow tube in the drain while you push the bathtub into the opening.

Level the tub

Once the tub is positioned, and the drain perfectly rests over the drain opening, then use a level on both sides. In case if any side is uneven, use hardwood shims to even the tub. Now follow the manufacturer's guide to secure the flange to the studs in the wall. Generally, one has to hammer roofing nails to secure it to the stud in the wall. In case of a metal bathtub, nail it into the above of flange.

Connecting waste-and-overflow piece

Depending on the position of the waste-and-overflow unit, connect the tail to drain line. Test for any leakages before you caulk the tub. Close the stopper to fill the tub and once filled, drain the water to test any sign of leaks.

Final touches

Do not worry if there is a minor gap above the tub. Use cement board instead of green drywall to make it more moisture-resistant. Now fit new tub surrounds that protect the wall that encloses the tub. Tub surrounds are essential to avoid moisture and mildew. Mark all the accessories such as faucet on the tub surround so that it is easier to cut out the opening later. It is recommended to measure it multiple times and then use a jigsaw to cut the opening. While there are tons of tub surrounds in the market, it is best to choose a one-piece surround that is much easier to install.

Finally, caulk the tub where the tiles meet the tub. Then run the silicone caulk around the perimeter of the tub. Now screw the surround at every 15cm to into each wall stud. Choose the silicone caulk that is special for bathrooms. Also, caulk the tub to the floor and then once again inspect all plumbing.

Now, connect all accessories to final tests. Give the caulk 24 hours to dry and then turn on the water to check for leaks.

The above is a detailed step-by-step guide to remove the old tub and install a new one. As a personal recommendation, it is always best to seek professional help to avoid any mishaps. They know their job well, and we can sit back and relax while the works are done.