I am installing a new disposal under a new sink to an old waste drain. The drain is metal. It looks like cast iron, but might just be thick copper. House was built in 1965.
The new single sink is deeper so the disposal sits lower. I have the correct connections via the trap and disposal exhaust but my pipes don't line up. The exhaust from the disposal is nearly at the same level as the drain pipe. Once I connect the trap to the waste pipe, the top of the trap is now too high for the exhaust from the disposal.
The kid at home depot says you cannot extend the down stream side of the trap which would lower the trap but allow the exhaust from the disposal to connect easily. Instead he suggested a pair of form-a-fit tailpieces to make the connections. I think this is a jack job but I think it will make the connections.
How should I handle this? Is this a common issue?