I am finishing my basement, which has a concrete floor. In the bath we are installing a whirlpool tub. I know I am going to have to build a raised floor for the tub in order to get the drain lines and trap in place, the drain for the tub was installed when we built the house and come straight out of the floor. My question is, how much room do I need under the tub in order to have room to connect the drain and trap to the tub (How tall will the trap and drain line be)? Thanks for your help.
If the drain line from the slab was designed for a tub when house was build ,it may have a trap under the slab already . To check, pour water into pipe and see if it holds water, if so you have a trap.
You cannot install the trap above the floor and still have a safe and legal installation. Doing that would create an “S trap which can be the same as no trap at all. Either the trap is already installed under the concrete, or you have to break the floor and install the trap in place of the existing riser pipe.