[ilsils]

After years of living with a flooding basement, we had a waterproofing company dig a perimeter trench in the basement, leading to a sump with a pump. For two years, we joyed at the dryness of the basement and, especially, the sound of water filling the sump and being pumped out (often at 5 gallons/min). With the flooding problem out of the way, we hired a contractor to finish the basement (new walls, new wiring, new carpeted floors in the living space, a new tile floor in the bathroom, etc.. . ) During the renovation, the plumber discovered that the sewage pipes beneath the concrete basement floor had corroded badly; these were the pipes leading out to the sewer and connected to pipes coming down the walls. So, the plumber dug out a large area of the basement, an area about 6 ft x 12 ft and to a depth of several feet, to lay PVC pipe. During the dig, he had to remove the black plastic tubing along the drainage trench. He then filled in the entire area with gravel stone, then put down a concrete floor.
Several months later, we had a hard rain, 2" in 24 hours, and I noticed a large area of wet floor in the basement. Even more discouraging, very little water reached the sump pump over the next 48 hours.
I fear that the plumber screwed up the drainage system that worked so well before he dug up the basement. He said that he did what was necessary and refused to admit that his construction was responsible for either the wetness or the lack of sump pump activity. So I called back the waterproofing company, and they dug through the floor at selected locations to ascertain the problem. We saw that the black pipe in their trench had been crushed, that the underfloor was not full of gravel (to the underside of the concrete floor) and, worst of all, there was standing water under the floor, probably extending the entire area of the dig.
The waterproofing people suggested re-routing the trench around the dig (which I will do). But I worry that the area that was (partially) filled with gravel will now become ‘lake basement’ after every rain, and the water – not able to ‘run uphill’ to the re-routed drainage trench, will sit for month evaporating and corroding everything accessible. It seems to me that the dig area should have been – and should be – filled with concrete, compacted soil or something that would not have become a lake, something that would have prevented water from collecting at a depth lower than the drainage trench. However, I don’t know the rules of construction in such circumstances, so I’m appealing for help from the experts on this matter. What should have been the correct procedure for filling in the hole? How should the drainage trench have been repaired? And, what should we do now to prevent water damage in the future?
ILS^2

[hkstroud]

Suggest that you repost this on the plumbing site. There are a couple of very good plumbers there that can give you knowledgeable opinions. I have my opinion but I am not an expert. In my opinion your assessment is correct and your plumber mucked it up. You probably should look for legal representation because you have an expensive repair.

[ilsils]

Suggest that you repost this on the plumbing site. There are a couple of very good plumbers there that can give you knowledgable opinions. I have my opinion but I am not an expert. In my opinion your assessment is correct and your plumber mucked it up. You probably should look for legal representation because you have an expensive repair.

Thanks, I'll repost it on the plumbing site.

[ballengerb1]

We can just move it.

[massplumber2008]

Ilsils... why do they want to reroute a new pipe around a TWICE PREVIOUSLY dug out area of floor... this suggests that they want to open up undisturbed concrete floor that is farther away from foundation wall. That does not make sense to me.

I would think they would want to open up the area of floor where they suspect the plumber crushed their pipe... then repipe... then add gravel... etc.

If they just reroute.. won't water be able to show up between old and new work??

I have some pretty extensive experience with perimeter drains... they should be run and covered to over top of pipe with gravel.

Anyway.. see if you can tell me why they want to do all that work when I think they should just work in area already worked in... fix that area... be done for good!

AND I will not comment on what plumber did or did not do... just be present as they open the floor... have a video camera and take pictures/video as you go.. Then, you decide what to do.

Hey, let me know. And if this answer helped please RATE THIS ANSWER by clicking on rate this answer. Thank you

[ilsils]

Ilsils...why do they want to reroute a new pipe around a TWICE PREVIOUSLY dug out area of floor....this suggests that they want to open up undisturbed concrete floor that is farther away from foundation wall. That does not make sense to me.

I would think they would want to open up the area of floor where they suspect the plumber crushed their pipe...then repipe...then add gravel...etc.

If they just reroute..won't water be able to show up between old and new work???

I have some pretty extensive experience with perimeter drains...they should be run and covered to over top of pipe with gravel.

Anyway..see if you can tell me why they want to do all that work when I think they should just work in area already worked in...fix that area...be done for good!!

AND I will not comment on what plumber did or did not do....just be present as they open the floor...have a video camera and take pictures/video as you go..Then, you decide what to do.

Hey, let me know. And if this answer helped please RATE THIS ANSWER by clicking on rate this answer. Thank you

I'm not sure which of us misunderstands what's going on. The plumbers, last October, dug up an area to replace corroded pipes with pvc pipes. The area crossed the drain system, which at this location, was the perimeter of the house, but adjoined a concrete pad that was originally the outside basement stairwell. That's how their area crossed the perimeter drain.
On Friday, the waterproofers dug a trench around the outside stairwell -- hence completed the true perimeter -- and connected it to a new trench from the perimeter to the sump. The new trench, which parallels the dig (in the only unfinished part of the basement) is about 6" deeper than the old trench. I watched as they finished the trench, water beginning to seep out of the 'lake basement' into the trench. I'm hoping this new, deeper cross-trench will reduce the height of water collected in 'lake basement'.

[massplumber2008]

I hope so, too. Sounds reasonable. Keep us posted as you go.

[ilsils]

I hope so, too. Sounds reasonable. Keep us posted as you go.

Three weeks and two 'weak' rain storms later, we've had:
1) no flooding in the basement
2)virtually no water in the sump pump, either!

I suspect that 'lake basement' is holding much of the water that previously made its way to the sump via the perimeter drainage system. Fingers crossed.:p

[massplumber2008]

Thanks for update... *fingers crossed* with you.. ;) Good day!