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How to Remove and Replace a Bathtub

Removing and Replacing a Bathtub

In most cases, removing an old bathtub is a project homeowners who are handy with a few common tools can do themselves. Removing an old tub is a labor intensive project and often involves some demolition of the area around the tub. Tubs can be heavy, so you may want to have someone help you when it comes time to take the old unit out of the bathroom.


Installing the new tub may seem like a daunting task, but if you are comfortable connecting drain pipes, you should be able to complete the installation yourself; especially if the new tub is the same size as the old one.




Step 1: Turn off the water

Before removing the tub, shut off the water supply. If your bathroom doesn't have a separate cutoff valve, you'll need to turn off the water to the entire house.  Open a valve at a lower level in your home to relieve any remaining pressure in the lines.

Step 2: Remove the drain and overflow

Tub drains will have different components that first need to be removed, so procedures on this step may vary. This one has a stopper that unscrews allowing you to access the drain flange at the bottom of the tub.


The drain flange itself will need to be unscrewed using a tool designed for tub drain removal. Now, use the screwdriver to disconnect and remove the waste and overflow valve cover on the side of the tub.


You'll also need to remove the tub spout since this will be on a portion of the wall you'll be cutting away. Some spouts have a set screw that holds them in place. If you don't find one, your spout should just twist off by turning it counterclockwise.


Step 3: Gain access to the drain

To disconnect the drain, you'll need to gain access to the underside of the tub, either from behind the wall or through the ceiling below the bathroom. You'll next need to use a pair of channel lock pliers to disconnect the pipes below the tee where the drain and overflow valve meet. If your fittings on your bathtub drain are galvanized steel, you may need a penetrating lubricant like PB Blaster to loosen the joints first.


Once you've loosened the nut connecting the drain pipe, unscrew it the rest of the way by hand and lift out the entire section.


Step 4: Separate the tub from the wall

To take out the tub, you'll need to cut out a section of drywall approximately 6 inches above the tub on each of the 3 sides. In order to make repairing the wall easier, measure a standard distance up from the top of the tub. Then use a straightedge to mark a guideline all the way around. Cut along the line with a drywall saw and remove the section between the line and the tub all the way down to the studs. 


Once you've cleared everything away, you should have access to the screws or nails attaching the tub flange to the studs. Remove these all the way around the top and sides of the tub with a pry bar. Before removing the tub, you'll also need to take off any trim molding from the sides of the alcove. Finally, cut away any caulk between the tub and floor with a utility knife.


Step 5: Remove the tub

You'll need a helper for these next few steps. One of you will lift up the front edge of the tub, while another slides a couple of 1 by 4's underneath it to get it off the floor. Now, carefully slide the tub out of the alcove using the 1 by 4's as skids. Finally, remove any stringer supports left on the wall. The stringer is the crosspiece that supports the edge of the tub.


With the alcove now exposed, clean the area and remove any nails or debris that's left over.


Step 6: Dispose of the old tub

How you dispose of the old tub will depend upon the type it is. Cast iron tubs should be broken up with a sledge hammer. Because of the sheer weight, you'll want to do this in the bathroom so you can remove the tub in sections. And because the pieces can be sharp, make sure you wear ear and eye protection at a minimum. All other types of material are relatively light, and the tub can be removed whole as long as you have some help. Steel, composite or fiberglass tubs can be cut up with a reciprocating saw. Porcelain over steel tubs should be disposed of whole.


Check with your local sanitation company for specific details on disposing of your old tub. Additional fees or restrictions may be involved.


Step 7: Choose a new tub

Before selecting a new tub, measure the width and depth of your alcove. Most bathtubs are 5 feet long, and either 30 or 32 inches wide. To find out what kind of tub you need, face the alcove. If the drain opening is on the left side, you'll need to purchase a left drain tub. If it's on the right, you need a right drain tub. If the tub you're putting in is a different size or orientation than your old one, you'll need to re-locate the rough-in plumbing. Otherwise, make sure it's in good shape, and replace any components if you need to before installing. 


Also, check to make sure the subfloor is level, and if needed use a leveling compound to even out the surface. Remember a space that's level, plumb and square is the key to a successful installation.

 Step 8: Protect the tub during installation

It's important to use caution when handling your new tub. Because the porcelain can fracture, keep it safely packaged until you're ready to install. Cut out a section of the cardboard to set inside the tub to help protect the surface against scratches and dropped tools. 


Now, remove the rest of the cardboard packaging, check the tub over and report any damage to the manufacturer. Finally, cut out a strip of cardboard and tape it to the exposed porcelain side to protect that as well.


 Step 9: Set the tub into place

Many tubs have a sound deadening and leveling pad on the underside, and this pad needs to rest fully on the subfloor. With your helper, carefully set the tub onto the skids and slide it into place in the alcove. 


Once it's in position, check to see if the tub is level, and if necessary use shims to even it out. Take a pencil and mark a reference line on the studs all the way around on all three sides. After doing this, take out the tub and set it aside.


 Step 10: Install the stringer

A stringer is a cross-piece support which will sit below the tub flange on the long side of the wall.


Since you've already marked the top edge of the flange on the studs, you'll need to allow for the height of the flange in order to install the stringer. Take the height and measure that same distance below the reference line on each stud. This new mark will serve as the top edge of the stringer you'll install. Cut a 2 by 4 the length of your tub, and use deck screws to attach it to the studs on the new reference marks.


 Step 11: Attach the overflow drain

To put in the drain, you'll turn the tub on its side and install it according to the manufacturer's instructions. Take a bit of plumbers putty, roll it in your hands and place it on the underside of the drain flange. Position the drain shoe on the underside of the tub, and screw the drain flange into the threads. Tighten it down completely with the drain tool and remove any excess putty.


To connect the overflow valve, place the rubber gasket onto the overflow elbow, and position it behind the tub. Attach the cover plate inside the tub to the overflow elbow and gasket behind the tub. Connect the overflow pipe and drain pipe with a tee where the two meet. Finally, install the drain strainer onto the flange.


 Step 12: Hook up the drain

Carefully move the tub back into place. As you do, make sure don't disrupt the drain assembly you just attached. When it's in position, the flange should rest on the stringer that was just installed along the back wall.


Make sure the drain and overflow plumbing coming out of your tub is aligned with the rough in drain outlet in your bathroom. Connect the pipes together and tighten them down snugly, but don't over tighten.


 Step 13: Secure and finish

Before securing the tub, make sure the top of the flange lines up with the reference marks you established earlier. If it does, go ahead and attach the tub flange to the studs with roofing nails. Note that you do not drill the flange. Instead use the head of the fastener to hold the flange down. Secure the flange on all 3 walls, as well as the sides of the tub.


With the tub in place, finish off the wall with drywall and paint. Reinstall the baseboard and finish molding around and in front of the tub. Finally, reattach the spout and the new bathtub installation is complete.