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back filling around drain line

We are in the process of building a bathroom in the basement of our 1920's house. The main drain line in the floor of basement was not where either the plumber or I expected it to be, and we ended up cutting up more concrete floor than necessary. All the plumbing work is complete and the trenches have been backfilled and closed up. The bad part is that I should have been standing over the workers as they covered up the line. Yes, they brought in new gravel and new concrete, and they didn't bury any of the debris, but when everything was said and done there was a ton of dirt - mostly clay - left over. We have never had water in our basement. All our neighbors have problem with water. When the floor was open and the material was excavated, it filled up with water the next day. I'm concerned that we may have had an impermeable clay layer under the floor that kept the basement from getting wet. Also, I'm worried that they didn't get very good compaction or there wouldn't have been so much material left over. The new concrete is at least 2 inches thick. We're about to tile the floor and I'm worried that (1) the floor may sink in the future and (2) water is going to start leaching through the floor now. At this point, I guess I just need to proceed and hope nothing happens. Maybe I'm over thinking this and just mad with myself since I should have thought it all out before the fact. Yeeks. Can anyone offer any words of encouragement?

Re: backing around drain line

I meant to title thread, "back filling around drain line".

Re: back filling around drain line

I a little concerned here. The most important part of the job, and you weren't supervising. Don't tile the floor yet.

1. Compacting the fill.
2. Did they use visqueen (plastic) on top of the fill and under the new concrete?
3. The slope of the new pipe.
4. The thickness of the new concrete.

Call the contractor and discuss your concerns and options at this point. Don't let him dismiss you.

Re: back filling around drain line

I have concerns about tying the old concrete to the new with rebar drilled into the old slab.

Head on over to the John Bridge Tile forum where ol' CX can give most excellent advice on the slab in prep for tiling. Take a few pictures of the area and start your own thread.

Re: back filling around drain line

There is no contractor to discuss the options with. The guys doing the work are being paid by the day. I'm the responsible party and the idiot engineer who wasn't doing the thinking. Your point about the liner and compaction are well taken. At this point I have two options. To dig it all up or proceed. The risk is that I may get water leaching into the basement, and I'll have to tear up concrete and tile. If I do it right now, I'll still have to deal with breaking up the concrete, and that's the horribly messy part. Maybe we won't see water. It's February, and in Maryland with clay soils, we should be seeing seasonally high ground water levels. If the GW was 8 inches below the floor elevation maybe it won't rise any further.

I'm going to ask my neighbors if there sump pumps have been running. Hopefully they have been. That would suggest that the GW elevations are high and what I saw under the floor is on the high side.

Re: back filling around drain line

I think you answered all your questions...

1. Cheap day labor is not cheap. At the end, it's very expensive.

2. If you already know that you will have a leak, and I'm pretty sure you will, correctly re-do the back filling again now, before you tile.

3. Even if your neighbors report low water level, always prepare yourself for extreme conditions.

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