Answers

Sounds like inadequate venting for the drain lines. Could have been build this way or maybe a clog has developed in the vent pipe. Such as birds or squrrels building a nest in the vent pipe up on the roof. You should hope that it's a clog, which can easily be removed. In order for proper vent pipes to be installed the walls will need to be opened up.

Dennis D. Gehman, MCR - Master Certified Remodeler & Master Registered Plumber

Gehman Design Remodeling

Harleysville, PA 19438

215-513-0300

www.gehmanremodeling.com 

Excellent question. Choosing the right Contractor is probably the most difficult part of the decision process, as you have to trust your instincts on complete strangers to work on your home. You increase your odds of a Contractor that will follow up to fix a problem by picking a Contractor that actually works out of a legitimate business  ( Brick and Mortor ) location rather than with a Contractor that operates out of their truck and or uses a PO box address. A Contractor in a brick and mortor location is easy to find and has made a long term commitment to their business.