Leaking Basement Walkout Entrance

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Supershine

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Hi everyone,

I recently had a basement walkout entrance built, but I've run into a problem.

It is a set of stairs running along the side of the house with the house foundation on one side of the stairs and a 10" poured concrete retaining wall on the other side of the stairs. The retaining wall is not sitting on a typical footing but rather a 6" poured concrete slab which also serves as the floor of the walkout. This was all designed by a reputable engineer.

The problem is that when I tried flooding the soil to get it to settle I found water seeping through the joint between the retaining wall and the concrete slab at the bottom of the stairs.

The wall is waterproofed with tar and the plastic waterproofing liner that you often see on foundation walls. In the pictures I took during the build I notice that it looks like the tar was not placed all the way to the joint at the bottom.

There is also a weeping tile connected to the original house weeping tile.

I have been told the following by three different people:

1. the older weeping tile may be blocked causing the new weeping tile not to work properly.

2. the leaking will eventually stop once the soil compacts in time.

3. don't worry about it because I had flooded it with water and that much water will never show up in one spot during a rainfall.

How serious is all this? I would love to hear some experienced opinions.

Thanks!
 
I beleive the frost level in your area is about four feet or close to it. So the footing of that wall and the exposed part of the foundation should be four feet below the surface of the slab.
The drain is often just set on top of the footing and if they did that using the slab as a footing, the drain is above the joint. Did they put a drain in the slab?
 
Yes, there is a drain in the slab. The top of the drain is level with the joint (with a slight slope to the drain) since the wall is sitting on top of the slab. The water leaking in will go to the drain.

However, I paid alot of money for this project and I thought no leaks would be a reasonable expectation.

In order to get away from the frost issues without going 4 feet down the engineer's design called for 4" of styrofoam beneath the slab and on the outside of the retaining wall.
 
I would be complaining about the leak for sure, given how it was built the water proofing should have included the slab, I would not usually as the footing is below the slab level in a house. Someone forgot to tell the waterproofer.

The frost level is worked out by how cold it gets and for what amount of time.
We have 18" because it never gets all that much below freezing and when it does it seldem lasts a long time. The foam below the slab will slow down the cold but for what time. It's not like insulationg a house where you always have heat on one side that you are trying to maintain. I am sure that there is a time the foam will give you for frost protection, I have not seen any info on that.
 
Tell me if I understand this correctly. Typically, a footing and the joint between the footing and wall are below the slab so it's not as important to waterproof that joint. This means water can get by that joint and under the slab and that is nothing rally to worry about. Is that right?

The issue regarding time of frost protection is interesting and I'll look into it, but I'm putting my trust in the engineer for the moment and hope he knew what he was doing.

Thanks for all the info Neal. You always have good insight to offer!
 
The fact that you have a drain in the slab says their drain should be low enough but I have seen the wall ignored and the drain just runs as normal. And yes we often see the pipe sitting on the footing on the outside and the slab is poored just above the footing on the inside but then in a walkout the footing is usuall much lower and so the drain will slope down to the lower level. So rain water coming down the wall should run into the pipe first and the lower pipe should pick up a raising ground water level?? Perhaps with your, if the slab is sticking out past the wall as footings often do and the drain is below that, the lip might be catching the water.

I have seen foam used like that , but is when after all the math was done and landscaping or something changed the elevation and someone says, dam what do we do now.

That perticular wall is never a retaining wall at it gets strength from the wall that joins to the basement and the staircase so they allway just get a simple footing and the slab is done with the stairs. So your engineer was over doing it while he got cute with making a slab out of the foot for the retaining wall. At the very least you need to let him know that it did not work.
 
So what is the perfect solution here?

Is it to parge the joint between the wall and the slab and then cover it with tar? Will that stop any leaking?
 
I think it should be dug up and waterproofed from the outside. That is what you paid for. Water will just find another path thru concrete.
 
That's what I meant. Parge the joint on the outside and put tar on it. Will that stop all leaking?
 
;) When you are standing on the slab you are inside, the outside is where the dirt is. Just to be clear
 
Yes, I got that. Waterproof from the outside and everything should be fine right?

Is it possible to waterproof it from the outside and still have it leak if there is alot of water (ie. alot of hydrostatic pressure)?
 
If you want to be sure run dimple waterproof sheeting down the outside to direct the water to the drain. This picture is on the inside but it is intended for outside use and used used mostly when the back fill material is clay

waterproofing-hamilton.jpg
 

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