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Thread: Need Sump Basin Advice

  1. #1

    Default Need Sump Basin Advice

    I've been thinking about totally redoing the sump pits in my recently purchased house and I need some advice and feedback for my plan to redo them.

    I currently have 2 clay sump pits, 1 that is attached to 4 inch drain tile and one that is not attached to any drain tile. The pit with the drain tile has the main sump pump and the other pit has a Big Dog battery backup pump and a water powered sump pump. There is a groove cut out of the concrete floor that connects the main pit to the backup pit and allows water to overflow to the backup pit without getting on the basement floor. I have attached a picture here that illustrates what I am talking about.

    What I would like to do, is consolidate the 2 pits into one larger basin. I haven't been able to find anything marketed as a sump basin that is the size I want, but I have found some sewage basins that are. I was looking at a Dayton 24"x36" sewage basin to use as a new sump basin. Is it ok to use a sewage basin as a sump basin? Also, would I need to drill holes in the bottom of the sewage basin to let ground water in that might be below the pit? Right now, it looks like water enter both my pits from the bottom as well as from the drain tile.

    Any comments will be much appreciated
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  2. #2

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    No it is not going to matter which basin you use, they are going to be made out of "poly" or fiberglass and both will do the job you want them to do!

  3. #3

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    Thanks ZP! I kind of had a feeling it didn't matter. After doing some more googling, I found some places that market the basin as sump or sewage. I guess I should have googled harder before asking that question I'm just happy to get confirmation of my suspicion.

    Also after cleaning out my sump pit yesterday I think I answered my own question about whether or not I need to drill holes in the bottom it. I found 2 larger holes at the bottom of my clay basins, large enough to get my finger through and feel the pebbles and muck underneath the basin. My only question now is, how large should I make the holes in the new basin? Large enough to get my finger through seems a little large. I was thinking around 3/8". Is that a suitable size?

    I can't wait to get started on enlarging my pit. I also look forward to being able to put a cover on it. Beside finding rocks and mud in my pit, I found a stick, a 2" screw, and a roll of electrical tape!
    Jason Baker

  4. #4
    Commercial Plumber markts30's Avatar
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    While you are fiddling with the plumbing, I would get rid of the rubber fernco style couplings and replace them with banded couplings (metal sleeves cover the rubber) they are less prone to blow-outs and are legal for use above ground...

  5. #5

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    Quote Originally Posted by markts30 View Post
    While you are fiddling with the plumbing, I would get rid of the rubber fernco style couplings and replace them with banded couplings (metal sleeves cover the rubber) they are less prone to blow-outs and are legal for use above ground...
    I'll keep that in mind. If I'm going to put the time and money into this project, I might as well do it right. I'll definitely look into them.

    Thanks to everyone who's taken the time to respond. Its very helpful. This is my first major project for my house and I don't want to mess it up. I also want to make it look as professional as possible. I hate hack jobs! My pits are a hack job squared because of the previous 2 owners taking short cuts

    Anyone have any recomendations about how large I should make the holes in the bottom of the basin so the ground water can seep in? Also, how far away from my basement wall should I try to place the new pit?
    Jason Baker

  6. #6

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    Well I have started doing some measurements in my basement and have come to the conclusion, I will not be able to use a large plastic sump liner. Upon further inspection of my floor, it also appears that the sewer line runs between my 2 sump pits. The house had a septic tank at one point but is currently hooked up to the city sanitary sewer. I don't know if the pits were dug before or after the sewer line was installed. Also the drain tile in the main sump wouldn't line up with the inlet on any of the plastic liners I have seen.

    The only solution I could think of for this problem would be to use a rectangular basin, but it doesn't look like that is something that is readily available. I've been googling all day trying to find them with no luck. Would it be possible to make my own basin by digging out my floor, making some forms and pouring a concrete one? If thats a terrible idea for whatever reason I'd like to know. Any input you guys may have would be greatly appreciated. I'd really like to clean up the current mess (see photo above) I have inherited
    Jason Baker

  7. #7
    In the Trades Bob NH's Avatar
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    You can make your own sump a lot easier (and better) than pouring concrete.

    Decide how big you want the sump to be.

    Dig a sump that is about 4" deeper than you want the finished sump, and about 16" to 18" larger diameter.

    Put some stone in the bottom of the pit. You can pour concrete if you want because with a clay soil you are probably not getting water in from the bottom. You can even make a porous concrete.

    Concrete will cure under water if you pour a stiff mix with a little extra cement, but you should remove the water before it is placed. Concrete should be mixed as dry as possible consistent with placing and finishing it, and then it must be kept at least moist during the curing time.

    Lay up the circular wall of the sump with loose block or brick, without mortar unless you know that there is no water from outside the pit. You want them keyed so they will resist collapse from external pressure.

    You can make an elliptical pit if round is not good but it should not have any straight sides (vertical straight is OK). If you need a layout for an ellipse post the length and width you want and I can give you the arc dimensions.

    I have seen landscape blocks that are trapezoidal shape that might be good. You can also use concrete bricks. If you use rectangular bricks to make a circle you should add mortar to the triangle at the joint to provide the keystone effect, but no mortar between layers. The joints will let water seep into the pit.

    You can run a pipe between the backup sump (if you keep it) and the new one at the lowest level.

    After the wall of the sump is laid, or as you are laying it, backfill with stone between the sump and the surrounding clay.

    When you get to the top you can work out the details for the finished floor and cover.

  8. #8

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    Interesting. I'm gathering that a rectangular sump wouldn't be structurally sound then. I appreciate your response Bob. I will investigate the block idea further. I was looking at making a 20" x 30" rectangular pit that would have been 30" deep. I have no idea what the arc would be for an oval. I'd have to look through my pre-calculus text book to figure that out. I also make no claims to being a mason either

    The main pit is filled mostly by drain tile but there is a hole in the bottom of the basin to allow water from underneath to seep in. The secondary pit is fed entirely by water from underneath the sump unless the main pit is overflowing. I was planning on eliminating the second sump completely to get some floor space back and to neaten up the plumbing.

    If anybody else has any suggestions, I would love to hear them also!
    Jason Baker

  9. #9
    In the Trades Bob NH's Avatar
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    A 28" inside diameter sump would have as much volume as a sump that has inside dimensions of 20 x 30 inches. I would find a way to put that in if it doesn't interfere with anything.

    Here is a design for a small sump with big storage volume.

    Determine the size of hole that you need for all the pumps you want to put in one hole. Let's say that you need about 24" diameter.

    Dig a hole about 42" diameter and 34" deep. Put 4" of 3/4" stone in the bottom and tamp it down so the finished depth is 30" deep.

    Get 30 8" half-blocks with large single core-holes. Lay them 10 to a circle with the holes up/down. That will give you about 24" diameter clear.

    Put a little mortar and stone (not filled solid) in the triangles outside but no mortar between layers. Stagger the vertical joints. Backfill the outside with 3/4" stone. Run the pipe through the wall and mortar it in place.

    After three layers finish off the top to support a flush cover about 28" diameter.

    The volume is much greater than a 24"diameter because of the spaces in the blocks and the stone. Water will come up through the bottom and through the sides. The spaces in the blocks will also store and yield water because the joints are not mortared.

  10. #10

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    Thanks for the response Bob! After sleeping on it and brainstorming some more, the 28" diameter regular round sump liner could be a possibility. My wife and I have been talking about demolishing the bathroom that is to the right of the sump pits for awhile. If we moved the pit to the right, we could probably use a large standard liner. I was trying to avoid getting rid of the bathroom right away, but the current sump setup works even if its not ideal. I think we'll just hold of on redoing the pits until we get rid of the bathroom and figure out where the drain pipes run underneath the basement floor. I'd rather take my time and do this right than bust up my floor and make an even bigger mess.

    I appreciate the time you took to respond. Thanks again.
    Jason Baker

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