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Jimmy 03-05-2014 07:29 PM

Seasonal water issues (basement)
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.

mudmixer 03-05-2014 08:02 PM

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.


nealtw 03-05-2014 08:29 PM

1 Attachment(s)
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.

Jimmy 03-06-2014 03:24 PM

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?


nealtw 03-06-2014 04:02 PM

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.

Jimmy 03-06-2014 04:06 PM

Thank you. Makes sense.

HandyLinda 03-06-2014 06:35 PM

would it be a bad idea to apply epoxy resin to the area you notice water coming through?

nealtw 03-06-2014 07:01 PM


Originally Posted by HandyLinda (Post 101421)
would it be a bad idea to apply epoxy resin to the area you notice water coming through?

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??

HandyLinda 03-07-2014 12:37 PM

That makes perfect sense, thanks nealtw.

guyod 03-07-2014 05:00 PM

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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