Planning Your Installation
A standard bathtub is 60 inches long by 32 inches wide. Choices such as a garden tub have larger dimensions, of course. When you’re designing your bathroom, you’ll want to leave room for the tub in your floor plan. If you are putting in a framed opening for the tub, it will have to be 60 inches long in order for the tub to fit. However, if it is more than 1/4″ too long, it is hard to make a tight seal between the tub and the wall. The framing has to be as close to perfectly square as possible.
When you’re planning your installation, you’ll also want to consider which material makes the most sense for your plumbing. PVC pipe works for the drain line coming from the tub, as long as it’s two inches in diameter. In some areas, cast iron drain pipe is becoming popular again, primarily because it works with less noise than plastic. You’ll want to bring in a pro to install cast iron pipe for you. If you want to use PVC but like the idea of it being quieter, wrap the plumbing with insulation.
Some people also prefer rigid copper pipe for water supply lines. In this case, bathrooms usually use 1/2″ lines. However, you can use 3/4″ pipe if you want to maximize water pressure, in the case of a shower/tub combination. In that case, you only need to use 1/2″ pipe for the short runs.