Bathtub installation is often done by professionals, but can be and often is done independently. To replace a bathtub requires lots of planning, so gather your tool kit ahead of time. Keep in mind this is not the kind of job that a novice wants to take on. There are many things that can go wrong and that means there is no substitute for a licensed, experienced plumber. Additionally, check your local plumbing code because this job may require an inspection by the local plumbing inspector.
The first thing you should do to replace a bathtub is measure the dimensions of your previous tub, so you know what to buy when you replace it. Measuring the width and length of the tub will also give you an idea of what route you will take to carry it out of your home, and whether or not you will have to remove the sink or toilet temporarily. Have some replacement bathroom tiles on hand; tiles can often break when you remove a bathtub.
Shut off the water to the tub, or the whole bathroom if that’s easier. Unscrew the overflow plate, and disconnect the drain. A special tool is required to remove it. Next, you should disconnect the waste and overflow (WO) unit under the tub. After that, you can begin removing the surface of the wall (probably tiles) above the tub. Cut through the caulk, and pry the tub away from the wall. It’s difficult to remove a bathtub alone, so get assistance after you pry it from the wall.
Now you can prepare for the bathtub installation. Repair any broken parts of the wall or floor. Make sure that the new drain and WO will fit properly. If so, assemble the drain in the tub, and secure the WO within the wall. Lift and slide the new tub into position, with assistance of course. Be careful as to not damage the WO or the tub itself.
Connect the drain line to the tub, and run some water to check for leaks. Secure the tub to the wall studs and caulk the seams where the floor meets the tub. If you don’t caulk these openings, then water can pool beneath the tub, causing structural damage to the floor. Install new faucets and tiles as needed.