Repairing plumbing pipes in Kitchen and Bathroom Floors is easier then many people think but if you have not viewed the inside of a home as it is built you may not know where to start.
To better understand how your pipes are placed in your floors you need to go back to when the home was framed. Framing is the part of home building where walls and floors are built out of plywood, 2×4 studs in walls and 2×10 boards for your floor joists.
The building begins by laying 2x10inch joists on top of your concrete walls of your foundation they are spaced 16 inches apart and run from the top of one wall to the opposite wall to allow the install of a plywood floor that you can walk on. If you have a two story home then 2×4 studs that are also your first floor walls will support the second set of floor joists for the second floor and plywood will be installed on top of that for your second story floor.
What you end up with is large areas between the floor joists 10 inches x 14 inches that are empty and can hold things like plumbing lines, heating, electrical and recessed lights.
On the bottom of the floor joists drywall is installed to provide a ceiling for the room below. If the pipes are in your first story floor then you may not have a finished basement with drywall and you will have very easy access to your pipes.
So, to make repairs to pipe that is in the floor you need to remove the drywall on the ceiling below the room you are working in or enter into your basement or crawl space area to access the pipe.
The only exception to this rule is when you are dealing with pipe that is located in the basement floor. The concrete floor of your basement should not normally have pipe in it unless it is to serve a basement bathroom. Waste lines that exit your home for higher floors should do so about half way up your basement floor or 4 feet below the top soil level outside your home to protect the pipes from freezing in the winter.
If you need to cut into your concrete basement floor then you will need a heavy duty concrete saw and possibly an electric jack hammer or at least a large 10 pound or better sledge hammer to break up the concrete.
If you are remodeling your bathroom there is never a need to breakup your entire floor unless you are moving fixtures and replacing the tile floor. Plumbing for your fixtures can be replaced and repaired by accessing the pipes below the room by removing the ceiling.