sewer tie-in excavation causing water in basement
#1
10-12-18, 06:16 AM
sewer tie-in excavation causing water in basement
Hi all - we are in the process of a sewer tie-in at our house. The contractor came in through the fieldstone foundation about 12" from the base of the foundation to run the lateral to the main at the street. Most of the excavation was not directly adjacent to the foundation except where the lateral enters the house.
The trench was backfilled at the end of last week and we just got a pretty good rain overnight. I awoke this morning to water literally pouring into our basement along the wall where the work was done about 6-8" off the floor. I mean literally pouring in. Most of the water is coming in away from where the hole was made to connect to the lateral (although there is some seepage there as well). We only got about 1-2 inches or rain, so not a anomalous storm by any stretch.
I'm wondering if this is to be expected with a recently dug trench that runs to the house (even though most of it is away from the foundation) and what could be done when they come back to clean up the yard to mitigate this from happening every time it rains? We've owned the house for 9 months and only had leaking in the basement one other time (on all four walls) during a big nor'easter that coincided with the winter melt. That was undoubtedly due to a high water table.
The trench was backfilled at the end of last week and we just got a pretty good rain overnight. I awoke this morning to water literally pouring into our basement along the wall where the work was done about 6-8" off the floor. I mean literally pouring in. Most of the water is coming in away from where the hole was made to connect to the lateral (although there is some seepage there as well). We only got about 1-2 inches or rain, so not a anomalous storm by any stretch.
I'm wondering if this is to be expected with a recently dug trench that runs to the house (even though most of it is away from the foundation) and what could be done when they come back to clean up the yard to mitigate this from happening every time it rains? We've owned the house for 9 months and only had leaking in the basement one other time (on all four walls) during a big nor'easter that coincided with the winter melt. That was undoubtedly due to a high water table.
#2
10-12-18, 06:24 AM
It sounds like whatever type of waterproofing there was on that foundation wall was disturbed. Also water will drain thru freshly filled soil quicker than it will thru dirt that's been in place for years. It sounds like you'll need excavate that wall and waterproof.
#3
10-12-18, 06:54 AM
That's what has me somewhat baffled - most of the area where water is pouring in was not disturbed at all (it's 8-10 feet from where the sewer drain was installed). There is also a gentle slope away from the house on that side, which seems to be mostly still in place, but of course the side yard is now a pile of clay-mud after all the work and rain.
I've thought about trenching and installing a french drain / waterproofing - I'd have to dig about 5 feet deep for 30-40 feet to trench that wall to the foundation base.
I've thought about trenching and installing a french drain / waterproofing - I'd have to dig about 5 feet deep for 30-40 feet to trench that wall to the foundation base.
#5
10-12-18, 07:44 AM
I have contacted them - I sent them the video of water streaming into the basement. In reply I got "holy s&!t - Its freshly dug so the water is traveling right through it". They still have work to do, so hopefully they can address the looseness of the fill in the trench to mitigate this happening every time it rains. I am worried about the integrity of the soil up against the foundation on that side though, since it took such a pummeling.
I went out to take a close look and there is definitely a lot of erosion of the backfill around the pipe going to the house & the fill over the trench is very soft. I'm guessing water is collecting along the trench from all the way out to the street (and maybe in the street under the soft patch) and funneling along the harder bottom of the trench right up to the foundation. It's all clay here (RI), so the undisturbed soil at the bottom of the trench will probably hold on to a lot of water - kind of like a pipe. So essentially, I have an underwater river running right up against my house. I hope it stops raining soon.
I went out to take a close look and there is definitely a lot of erosion of the backfill around the pipe going to the house & the fill over the trench is very soft. I'm guessing water is collecting along the trench from all the way out to the street (and maybe in the street under the soft patch) and funneling along the harder bottom of the trench right up to the foundation. It's all clay here (RI), so the undisturbed soil at the bottom of the trench will probably hold on to a lot of water - kind of like a pipe. So essentially, I have an underwater river running right up against my house. I hope it stops raining soon.
#6
10-12-18, 11:12 AM
They still have work to do, so hopefully they can address the looseness of the fill in the trench to mitigate this happening every time it rains.
One common response is to spread bentonite powder- a swelling clay- into the top layer of the soil, idea is that the fine clay will work it's way into the pores of the soil.
It's a common old-time solution for leaky man-made ponds.
#7
10-12-18, 01:36 PM
I hope it's just ground water coming in . . . . and not your neighbors' sewage.
Do they routinely install back flow preventers on your municipal sewage lines ?
I once sat on a Conservation Commission where we were inundated with complaints about storm sewers surcharging the sanitary sewers every time it rained, and the sewage would backup into the basements of anyone who lacked a back flow preventer.
Then the Fire Department had to go out and sanitize the basements involved . . . . but everyone knew what the others had for dinner the night before.
Back flow preventers are very valuable.
Do they routinely install back flow preventers on your municipal sewage lines ?
I once sat on a Conservation Commission where we were inundated with complaints about storm sewers surcharging the sanitary sewers every time it rained, and the sewage would backup into the basements of anyone who lacked a back flow preventer.
Then the Fire Department had to go out and sanitize the basements involved . . . . but everyone knew what the others had for dinner the night before.
Back flow preventers are very valuable.
#8
10-25-18, 06:08 AM
There is a back flow preventer installed near the property line, so it is groundwater / rainwater. The work is complete and I've been watering down the area by the trench for both the new grass seed and to help settle the fill in and around the trench. Still getting some erosion at the connection by the house (filling as I go), but thankfully there hasn't been to much rain. I had the guys build a cold patch berm at the property line, but rainwater still funnels down the street and into the cold patch at the road, presumably filling up that trench - no street drainage continues on past the patch, as it sits lower than the surrounding road. Hopefully the water won't make its way down the trench again, but I imagine most of this will be solved once they pave the patch in a month or so.
