I just purchased a 30 yr old condo and I seem to have a leak under the second floor master shower. A plumber went out and said the leak was caused by NOT having a shower pan. What would be the best and cheapest method to fix this leak problem? I've thought about getting a company (like bathfitter's) to install over the old, but how would i know whether there has been any damage to the floor? I've also heard that places like Bathfitter's are very expensive.