Just demoed a new bathroom which was done only a year ago. Tiled pan and Homeowner who just purchased the house had a leak on the first floor.
The ceiling bellow was opened and further investigation reveled sub-standard work.
Today we took the pan out, and what you know, no positive slope towards the drain was created. instead a few wood shims were nailed along the edges to create slope...Then garbage bags where laid out and stapled to the studs, instead of rubber liner or other waterproof material available today(you can see the tie flaps of the garbage bag in the picture), then 1/4" hardiebacker was laid on top of it and tiles. The curb was made using red brick.
What a mess and the sad thing is, they knew there should be a rubber liner, but instead they used garbage bags, I just don't understand some of this so called "contractors" out there, who take money from Homeowners and do this kind of a job.
Another valuable example why Homeowners should hire licensed contractors... the job will be done right and it will last for many years to come.