My question is, right now from the subfloor to the bottom of the flange is 1 3/4". I have to add 1/2" cement board, redguard "painted membrane" and then the tile. I'm looking at about 1" up from the subfloor. so that still make the flange 3/4" of space from the finished floor to the bottom of the flange. What should it be? The old floor was tile and over an inch of concrete and wire. House was built in 1961. Second question, the sewer line is a 3" copper line with a brass flange, if I have to lower it, i figure I have to torch the pipe and hope it come off, then cut the copper pipe back and then reinstall the brass flange? thanks

Hello, We have lived in our house now for 8 years. Everything has been fine up until recently we have been hearing knocking in the water line. It seems to happen when you start the dishwasher or start using the kitchen sink. When you start running the water after about 20 seconds or so you here one knock in the pipe ( not very loud) and it is a single knock that is repetetive about every 6 seconds. If water keeps running it will go away after a minute or two. I have been down in the basement and it is hard to tell exactly where it is coming from but i would guess the hot water side as that is what the dishwasher uses. i mentioned to someone at work and they mentioned it could be a water regulator if one is present. I investigated all around the water meter in the basement and where incoming water comes in and I see no regulator. pipe comes through the slab to the water meter and then straight piping throughout the basement. Also, No changes to the plumbing system have been made other than installing new sinks and a hot water heater a year or so ago. Any thoughts what could cause this knocking to start up. Thx