Question: I live in Thunder Bay. A few years ago, I had a backwater valve installed. The pit continuously fills with water and my husband drains it daily. I’ve had a few plumbers inspect it and nobody seems to really know what I can do. They suggest putting in a sump pit to lower the water table and then all the water will go to the pit rather than the backwater valve pit. I never had any problems prior to this pit being installed. The problem is we have floating vinyl floor over the concrete floor and all the new concrete poured over the backwater valve piping seems to seep moisture and cause mould under the floor. The plumber who did the job will not return our phone calls. He also put a bathroom in downstairs for us and we had many problems and had to have another plumber fix it all.
I am wondering if you have advice?
Thanks, Katrina O’Brien
Answer: Poor workmanship by some subtrades is an unfortunate reality in today’s homebuilding or renovation climate. Sometimes you just have to bite the bullet and hire a more experienced contractor to repair or replace the work done by the shoddy tradesperson.
Installation of a backwater valve should be a proper part of installation or retrofitting of a bathroom in a basement. Installation of this plumbing device will require partial breaking up of the basement concrete floor slab, excavation, and patching of the floor where the concrete has been removed. There may be numerous reasons that you are seeing excessive moisture on top of the valve cover and in the concrete and none of them are typical. The most serious could be poor connection of the valve piping to the existing drains, which can lead to waste leaking under the slab. If this has occurred, there is no choice but to break up the floor, once more, and repair the leaking pipe. Left unchecked, this could lead to a health concern with sewer gas infiltrating the living space and waste contamination of the soil underneath the floor.
Another possibility is that your home may have a polyethylene air/vapour barrier membrane installed under the concrete slab. This thin sheathing is installed in homes to prevent soil gasses from entering the basement through the concrete. It also will serve to prevent wicking up of moisture from damp soil under the slab, in homes with high water table or other moisture issues.
Worrying about the exact reason for the issues you are facing may be a bit of waste of time and energy. Since other plumbers have not been able to determine the cause, it is likely hidden under the patched concrete. Unfortunately, the only solution may be to completely redo the original installation, properly, to prevent a reoccurrence. Since you are also having some issues with the new bathroom, an experienced Red Seal plumber should be hired to remove and reinstall the backwater valve and fix the poor workmanship issues in the bathroom, as well.
Another option to think about when repairing the shoddily installed valve, would be to install a sump pit and pump, at the same time. This is often done when a new backwater valve is installed, to prevent flooding of the basement during a sewer back up event during a heavy rainstorm.
It may seem like you are in an unresolvable situation, with no solution to the problems caused by poor workmanship for your basement bathroom by a slipshod plumber. Fortunately, there is a solution, but it likely requires complete removal of the backwater valve and replacement.
trainedeye@iname.com
