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Discussion Starter · #1 ·
we've had about 8 to 10 inches of rain in the past 2 weeks. i'm wanting to dig a new sump pit in my basement, should i wait for a drier time, or would it be ok to go for it?
 

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Chicago, IL
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First step is to try to eliminate or reduce water seepage into the basement, take a look here for suggestions:

A Visual Guide to Common Causes of Flooded Basements - Paragon Home Inspections Chicago / Skokie / Northbrook IL

A Sump pump is usually not installed to collect water as it flows across the floor or to extract water from underneath the slab (which can undermine the slab or even the foundation's footing) but rather to extract water from a perimeter foundation drain system before it enters the basement or crawl space:



Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson


 

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Discussion Starter · #3 ·
trying to fix wet basement

Thanks for the reply. I don't currently have a sump pump or pit, I was curious if the current wet ground conditions would interfere with the installation of one or if it would be better to wait until the ground dries out ? Thanks for any input
 

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Depends on your actual water level and soil types. You MAY be digging underwater. "IF" you have playbox sand type soil underwater it will NOT work. The wet sand (and water)will flow into the hole 10 times faster than you can dig it out!! BTDT!!! I used to live where certain times of the year it was impossible to dig a post hole. If you absolutely HAD to have one someplace,,,you pushed it into the ground with a loader. digging a sump hole would be roughly the same. Clay soils can be dug while under water. Some method of water removal may assist the efforts. Even a small depresion with a sump pump kicking out the water may help. Dryer weather MAY help,but just cause the sun is shining doesnt mean the water level is lower!!
 

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Will this just be a collection point for water flowing off the top of the floor slab, or do you intend to use a perforated sump or some other method to attempt to de-water the soil below the slab?


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Meanwhile, you may be able to use a "Floor-sucker" pump.

Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson
 

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Discussion Starter · #7 ·
The water comes in from a floor drain that is suppose to pit out somewhere. We've tried to follow it but lose it somewhere under the driveway. uknown if that is where the original pit for it was or if the pipe/tiles have just collapsed.
 

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When I moved into my house 19 years ago, we encountered a similar situation. No sump pit, it rained about 8 inches two months after I moved in, flooded basement. I was successfully able to dig a sump pit and install a pump under water, here is how I did it.

First of all, you are going to need to break the concrete to install the pit. I had about 3 inches of water above the slab when I did the work. I used an electric jackhammer attached to a ground fault interrup circuit. I wore rubber boots, even so probably a pretty dangerous way to cut the slab. Better off using a pneumatic hammer to cut the opening, you can rent one. I did not have the money at the time.

I chipped out an opening about 24 inches in diameter, with the intent to install a 20 inch diameter perforated bucket, 24 inches deep, to collect water, which would be pumped out to a low area in my yard about 150 feet from the house via a 2 inch diameter PVC drain line.

Once the concrete was removed, I dug the rest of the hole by hand, with a flat bladed shovel. Since there was gravel beneath the slab, it wanted to collapse, so I used wood staves about 3 feet long driven into the gravel beneath the slab to hold the gravel back. I borrowed this technique from commercial trench diggers, who still use it to this day on large projects (the sheeting is locally known as Wakefield sheeting). Simply temporary wood sheeting to hold back the soil while digging.

Once I had the hole dug to the proper depth (24 inches), I inserted the premade plastic tub made from a plastic garbage pail, with 3/8 inch diameter holes drilled into it. The sump pump went into the bucket, and I connected the sump to a dedicated outlet with a ground fault interrupt. Fortunately the outlet was already there, I don't think I would have wanted to wire when the floor was still wet, which it was. I set the float level to turn the pump on when the water was 6 inches below the slab, and to turn the pump off when the water dropped to 12 inches below the slab. This keeps the pump wet at all times, which is necessary for a submersible pump.

I dug the trench for the 2 inch PVC line by hand, I only buried it about 16 inches, which is not below frost depth, but to dig below frost would have been a huge job. I initially used a backflow preventer on the pump, but after several years of periodic freezing of the line in the winter, I got rid of the backflow preventer, and the system works quite well. It has been working fine for about 18 years now. I use an industrial grade, 1/2 HP, 100 volt Barnes sewer pump with 3/4 inch solids handling capability. Due to the variations in groundwater in my yard, the pump typically only works three or four days a year, but it is quite effective in keeping the basement dry.

Now as for the comments about connecting the pump to an exterior drain line, this is a great idea, assuming your house has an exterior drain line. Mine does not, and it would be quite costly to install one. Because my slab was place on at least six inches of coarse gravel, water beneath the slab flows through the gravel to the sump, where it is ejected. If your slab is not built on gravel, this will not work, and you will need to use a different plan.

Based on experience, it would of course be easier to wait until the water recedes to dig the hole and install the pump, but it CAN be done in the wet. Be safe, if you use electric tools make sure they are double insulated and connected to a GFI outlet, even then I recommend using pneumatic tools with a compresser, much safer. Good luck.
 

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If the water is coming out of a floor drain call a plumber to snake it out and camera it it could be something as simple as your sewer line being stopped up Or if on a septic your tank might be full or drain fields have failed.
 

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Discussion Starter · #10 ·
thanks for the advice. sound alot like what i'm planning, only i dont acctually have any standing water in the basement. don't know why, but i'm kind of looking forward to the project, hoping for the best. thanks again for the info.
 

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Discussion Starter · #11 ·
i do have a good mxture of clay in the soil, but not a bunch. also have a floor sucker pump that i am plannig on using if water comes in when i start digging. thanks to all for info & help.
 

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As Daniel Holzman's post demonstrates if you have the right kind of soil a "perforated basket" type arrangement can work satisfactorily.

However if you have the wrong kind of soil (were example, my house is built on a medium grained sand) and you start moving substantial amounts of water under the slab and foundation footings you may start "washing out" the material supporting your foundation.

It's easy to tell if you potentially have this problem, if you do you will start seeing substantial amounts of solid material deposited in the bottom of your sump (enough so so that you have to remove it regularly).

If this is the case, I would suggest you stop operating the pump - that soil is coming from somewhere underneath the slab or foundation.

Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson
 
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