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View Full Version : Is basement trench needed if sump pump has been put in ?


Str8stack71
Jan 20, 2009, 12:08 PM
Hello, I'm wondering if someone could give me their thoughts.. our house is 40 yrs old... there is a trench along bottom of basement walls... however, about 15 yrs ago, the people that used to live here put a sump pump in the floor down there. Do we still need the trench if the sump pump is pumping the water out from the gravel below the floor? I'm wondering if its possible to just fill in the trench... basement has never leaked or flooded... but sump pump does run after hard rains or heavy snowfall melts...

Thanks

21boat
Jan 20, 2009, 01:07 PM
I'm not sure how wide or deep the trench is but here's how we handle that on the job sites.
Depending on how wide the trench is We make sure it is at least 4 or more inches deep. Clean out the crushed stone and check your depths. Put a rice mix stone as a 1' base down. Now get a 1/2" pvc or 3/4"pvc water line and drill weep holes in it smaller than the size stone you use. The more holes the merrier. Lay that pipe and connect it all and run it to the sump pit. Now add more crushed stone and fill up trench to with in 1" to 1 1/2" of the finish floor. Get some ready mix concrete bags and fill up the last 1' or so left in the trench. This will help to close up the trench and still let it work properly.


Signed 21 Boat

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Str8stack71
Jan 20, 2009, 01:13 PM
Excellent... this is the exact answer I was looking for... thanks, I appreciate it.

Str8stack71
Jan 20, 2009, 01:19 PM
OK, let me ask this... does the pipe need to have fall so the water goes to the sump pump?. or should the pipe be level... if the pipe is level, will the water drain properly to the sump pump?
The trench is only about an inch wide, maybe a bit more,

21boat
Jan 20, 2009, 03:13 PM
No it really doesn't need fall. Water seeks its own level. The pipe is just a little quicker way of getting water to the sump pit. The stone around it will send a lot of water naturally. The pipe just speeds this up by no resistance of obstructions in it for heavy rains that may come in. The pipe is a quicker delivery system to pit. The 3/4 to the 1" gap was created by either a board set in during conc pour or more commonly we use polystyrene foam board to trowel crete to and then pull it out and that's easier than a swelled wood board getting stuck in the gap needed. So again the pipe not sloping perfectly is fine and that's the beauty of this installation. Try to maintain some sort of levelness. Dead level is perfect but a little off won't diminish its capability's gravity will see to that

logan176
Jan 20, 2009, 07:36 PM
If the trench is only about an inch wide, then sloping it probably won't make any difference. I have 4" diameter weeping tile in my basement under the floor and I made sure to slope it toward the sump pump because there is a high water table in my development.

21boat
Jan 21, 2009, 03:20 AM
Hi logan I have the worst one yet. I built a home for a customer and there was no water in the basement hole the whole job. Well Murphy stopped in. I got a call on Christmas that there was water in the basement 2 inches deep. I already had drain tile on outside plus a pit that connected to buried. I installed sump pump. It was barely keeping up. So Again bite the bullet There was a sloped grade away from house and the street in front of the house way 75 feet away and 3" below inside basement floor. No water in street. I ended up piping a grid on new floor with 2b clean stone on that then 3 1/2 inch new pour floor on that. broke a hole through wall and hoed in a very slight transit shot trench to street side. It still working today since 1985 and the water still at times runs. Thank god all of the stone I put on outside of house and under first conc floor and the next floor with 4" stone under that. So house foundation doesn't erode away. The owners cal it there falling waters By Mark our builder. Wwwooooohhhh Lost my shirt but home and customers are still standing.

logan176
Jan 22, 2009, 04:07 PM
When I installed my sump pump it was cycling every 30 seconds for 2-3 weeks. Then about every 2-3 minutes for another 2 months. I hate being right next to a creek. I was just happy that my town allowed me to connect my discharge pipe, that I buried under the ground, to the sewer grate right outside my house.

You never know what's under your house. And just as 21boat said, you can do everything right and still run into unforeseen problems down the road. Kudos to 21boat for going back and busting his rump... to me, reputation is more important than price. There is a contractor I call whenever I come across something I can't tackle alone. He's not the most expensive guy out there, but he's definitely more expensive than average. But, when the guy comes to work I give him a key to the house. We should all feel a little grateful that there is a forum like this where even if you can't do the work yourself, you can learn enough to be able to keep an eye on the people working on your house.