I am installing a shower over a 2ft x 2ft hole in the concrete slab used to place the p trap. My question is: Doesn't this area need to be sealed off with tar or something? Or do you just leave the p trap in open dirt? Also, when I place the drain in the shower by connecting it to the 2 inch pvc drain line how do I get this thing sealed with plumbers puddy and still get the pvc cemented quickly enough. It seems there is not enough working time with the pvc cement to place the puddy on the flange etc. Is there a way to retard the set of the pvc cement? Thanks for your help

Charlie

You can buy a slower acting cement for the PVC. And yes I think you need to seal underneath the shower base with a concrete or something to keep the ground living insects from getting into the house area.
Be very careful in doing your measuring, make sure that the riser form the trap is directly in the center of the hole in the shower so that the pipe and the fitting in the shower will line up when you put it over it, also make sure that the height of the drain pipe is the right height. One other thing is the cement that you might put under the shower base might hold the pipe secure while you put the base down over the drain.