Seasonal water issues (basement)

Discussion in 'Framing and Foundation' started by Jimmy, Mar 6, 2014.

  1. Mar 6, 2014 #1

    Jimmy

    Jimmy

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    Improving exterior grade, snaking the foundation drain, cutting down all the trees who's roots plugged the foundation drain, and draining the sump line and downspouts to the nearby creek, via solid pipe, has reduced the water in the basement of my fixer upper from a 1/2 inch of water to a couple seasonal nuisance puddles in my basement.
    I would like to get rid of these as well.
    I suspect that my block wall foundation is leaking, although there is no water penetration visible on the interior of the wall.
    The water appears where the wall meets the floor. Having done some excavation in the rear of the yard, I am also aware there is water about 8 feet down in the fall.
    I also have a creek 20 ft from the North wall of the house, which I believe would make exterior waterproofing efforts unwise.
    Given these factors, I believe a perimeter drain under the basement floor is my best option, unless someone here could convince me otherwise.
    I intend to tackle this job myself but am unsure of a couple details.

    Does the basement floor sit directly on top of the footing? If so, I understand it is advisable to drill a hole into each pocket of the cinder block to allow water to get to the drain tile. If the tile is next to the footing and the floor is on top of the footing, what would be the best way to get the water from A to B? Would a plastic tube be sufficient?
    What size should the holes in the block be?
    Should I pin the patch in the concrete the way I do when I repair a road?
    Does there need to be an expansion joint or some other sort of separation between the slab and the foundation wall?
    Is it better to wait until hydrostatic pressure is low, or can I do this job in the spring?

    Hope this is not too many questions. Want to have a plan before I cut the floor open. Thanks in advance.
     
  2. Mar 6, 2014 #2

    mudmixer

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    Your situation is very common.

    The walls are usually sitting on a strip footing just like many concrete walls. The 4" floor slabs on these are usually poured late in construction and are poured on top of the footing. The joint between the wall and the floor is subject for leakage of water below the floor that is also forced in by the exterior soil weight. The slab shrinks and pulls away slightly.

    An interior drain (during or after construction) is laid on a coarse sand and rock base with the bottom of the pipe at or below the bottom of the footing (usually 12" below the top of the floor slab - 4" slab and "8" thick concrete footing).

    A good system with block will take advantage of the cores by insert a piece of 1/2" (more more) flexible plastic pipe into a hole into one core of each block. The pipe is directed into the fill area around the perforated pipe before pipe is covered with the sand/rock combination.

    The holes in the block should be just large enough to get the plastic into and the concrete for the slab will close the gap around the plastic. I know of a GC/builder that had a special block made with a hole in each block, but he sold several thousand homes and never wanted to ever have a complaint about a wet basement - He also had drain tile and plastic pipe on the exterior as a standard construction detail and was a minimal cost on new construction.

    Dick
     
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  3. Mar 6, 2014 #3

    nealtw

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    Welcome to the site. It is always better to drain and waterproof from the outside but sometimes you have no choice. It looks like you have done your homework.
    Usually when a block wall is leaking you will see moisture on the inside to the level that the water has filled the block. You maybe fighting a high water table but the fix is about the same.
    Where the footing should be and what you find maybe a little different. The footing should be deep enough to sit on solid soil and the bottom of it should be at the frost level for your area. If your area has a 48" frost depth the bottom should be at 48" below the ground level outside or just below the slab or deeper depending on soil conditions. If you have a deep basement in the front and walk out in the back the footing level should step down to give frost protection at the back.
    Your best bet would be to lay the pipe along side the foundation or footing and run dimpled waterproofing plastic down the wall, bent at the bottom to cover the pipe, then you won't need pipes.
    I (believe ) 3/4" holes are the standard, but you could find that they are full of concrete and holes will not help.

    interior-015.jpg
     
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  4. Mar 6, 2014 #4

    Jimmy

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    Thank you both for your competent answers. I am feeling much more confident.

    Would you hesitate to do this job while hydrostatic pressure is high?

    Thanks
     
  5. Mar 6, 2014 #5

    nealtw

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    I would think the whole job will be easier if you are not working in mud or water, I think I would waite a while.. The floor does add latteral support for the foundation wall, if you have mud push on the side,you know.
     
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  6. Mar 6, 2014 #6

    Jimmy

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    Thank you. Makes sense.
     
  7. Mar 7, 2014 #7

    HandyLinda

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    would it be a bad idea to apply epoxy resin to the area you notice water coming through?
     
  8. Mar 7, 2014 #8

    nealtw

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    There are products to treat the inside of concrete but with a block wall the blocks will fill with water until it gets to an untreated area, best is to relieve the pressure by getting rid of the water. Foundations are designed to hold up the house and hold out the dirt but they are not really retaining walls so if a leak is showing up higher on a wall, how more weight to pushing on the wall and how much can it take??
     
  9. Mar 7, 2014 #9

    HandyLinda

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    That makes perfect sense, thanks nealtw.
     
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  10. Mar 8, 2014 #10

    guyod

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    With a creek that close to his house is it really a good idea to try and pump as much of the ground water out as you can. I would think over time the water will create a channel from the creek into the pump from the thousands of gallons of water he will be pumping. Turning a few wet spots into a few feet of water if the pump stops working. I would put a couple coats of drylock on walls and floor and see what happens.
    I have a spring stream about 20 feet from my house house and when it is running so is my sumb pump.
     
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  11. Mar 9, 2014 #11

    Jimmy

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    Already did the drylock. Thanks for the suggestion though.
     
  12. Mar 10, 2014 #12

    slownsteady

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    I used the dimpled plastic on one wall of my house that was showing sign of seasonal weeping. It has been working like a charm.

    Jimmy, if you do this from the outside I would advise waiting for the summer. Is your nearby creek seasonal? You most likely want to wait if that is the case.

    Once i had the trench along the wall dug out, i had to wait about three weeks for the block to dry completely before I could start waterproofing. The block wall was visibly damp when first dug, but I was really surprised that it stayed that dark gray, damp color for so long. Some spots were worse than others, and I even put a blower in place to speed things up. Once the wall turned the lighter gray that is more familiar, then I applied a fiberglass sealer to the wall and put the dimpled plastic against that. A drain pipe and gravel at the bottom of the trench completed the system.
     
  13. Mar 11, 2014 #13

    Jimmy

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    The creek does usually dry up for a few weeks in late July early August. When it is high is when I have problems. I am aprehensive about loosening the soil on the outside as I think that will invite more water than placing a drain below the basement floor.
     
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  14. Mar 12, 2014 #14

    nealtw

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    If you are thinking, if you disturb the soil you may be asking for trouble, keep in mind that the soil around your house has already been disturbed. I understand why people don't want to dig on the outside, along with all the other arguements, it can be a dangerous place to work. But the arguements for doing it on the outside should also be considered. On the outside you could oversize the pipe and add a second pipe for the downspouts, waterproof the wall and never worry about the weight of mud pushing on the wall.
     
  15. Mar 12, 2014 #15

    slownsteady

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    What kind of soil do you have? When you say "disturbing the soil" are you worried that the walls need the support or that the water may get worse? 'Cuz if you do it right, the new system will carry the water away.
     
    Last edited: Mar 12, 2014
  16. Mar 12, 2014 #16

    guyod

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    Is the water in the creek higher than the basement floor?
     
  17. Mar 14, 2014 #17

    Jimmy

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    The water is sometimes (infrequently) higher than the basement floor. It is right now, but I am still dry for now. The five feet of frost we had this year might be helping for now.

    I have 12 inches of nice top soil and then hard clay. My concern is by loosening soil on the outside of the foundation I will create another "point of least resistance" for outside water (especially ground water). Since I don't have the ability to drain a foundation drain to daylight without a sump pump and draining to the sewer is against local code, I am apprehensive about introducing more water to the drain system than necessary to dry the basement. The gutters are already drained to the creek via solid pipe.

    It would probably be easier for me to do the outside. I am an equipment operator for a living and could dig around the house with an excavator in no time, as opposed to lugging concrete up and down the stairs. I fear that a high water table is my problem though, and I don't think this would correct water pushing up from under the floor.

    That is why I am leaning towards the drain under the floor. Does this sound logical?

    Thanks to everyone for the input.
     
  18. Mar 14, 2014 #18

    guyod

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    If it was me I would install a sump pit without the perimeter pipe. I wouldn't want to collect more water than needed to keep basement dry. There should be a layer of gravel under slab that will drain water to pit.
     
  19. Mar 14, 2014 #19

    slownsteady

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    So where are you going to pump that water to? That part would be same whether the drain is under the house or beside it. Someone can correct me if I'm wrong, but hydrostatic pressure would be responsible for pushing water up through the floor. If that a problem now? It may require a separate solution from waterproofing the walls.
     
  20. Mar 14, 2014 #20

    nealtw

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    It does sound like pressure from below and I suggested the dimpled sheet on the inside to make sure there was no future problem with the walls. The but is hiow strong is the block wall compared to a concrete wall, around here we never see block wall but when the soil is clay the dimpled sheet is required on the outside and when you have sandy soil it is not required. The difference is the weight of the soil pushing on the foundation. A foundation wall is not a retaining wall. If I had access to a digger I would make that discussion last about as long as a N.Y. minute.
    Depending on depth, if you can't drain to daylight, perhaps you could a foot higher, then I would run a pipe around to a pump, run a foot of gravel cover the ditch with poly and round another pipe to daylight. The higher pipe would drain water coming down thru the soil and the pump would deal with the lower water that would be a problem in the basement.
     
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