In order to protect the plumbing from the concrete during the pour, after the pipes for Showers, Toilets and Bathtubs are cut to 1/2″ below the finished surface, sealed with duct tape and then protected with cardboard. For the toilet drains, three layers of cardboard is fitting around the PVC and one layer of cardboard is cut to size for the top. For shower and tub drains, a cardboard box is cut to the correct height, filled with filldirt and sealed shut. A small amount of fill dirt is placed on the box flaps to hold its position. This allows the concrete to be poured and smoothed right over the tops of these drains. After the pour, the openings can be accessed by chipping away the small amount of concrete on the tops.
Toilet drain dab-outs are slightly different, so a separate set of photos also follow:
The excellent multi-tool is of course my favorite
It works very well on the job site 🙂