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Interior perimeter drain. Trying to identify foundation

Interior perimeter drain. Trying to identify foundation

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  #1  
Old 02-07-14, 06:05 PM
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Interior perimeter drain. Trying to identify foundation

Hello.

I'm planning on digging a perimeter drain in my basement to alleviate a water issue I've been having during heavy rains. All my gutters are clear grading is sloped etc and excavating the exterior of the home is out of the question due to cost.

I live in a 1930 craftsman style home on a decorative looking block foundation which appears to have been parged from the inside at some point. I decided to open up a small hole to get a peek at what I'd be dealing with. It looks like the slab is only about 2 inches thick. I cant tell if the block extends below the slab or its just more slab under the block due to the parging. The wall extends out roughly 1/4 inch past whatever is beneath it. It goes down about 3 inches below the wall and then I can basically tunnel underneath with my hand. Im concerned with excavating the perimeter due to the fact that there doesn't appear to be a footer. Ive attached a few pictures to help. Sorry about any confusion and thank you in advance.
 
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  #2  
Old 02-07-14, 07:06 PM
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You may have two different foundation materials. It is possible the foundation was poured concrete to the grade line and then capped with the rock faced concrete hollow block above that point to get the decorative appearance.

While not the most sensible thing to do, foundations of poured concrete in that era were sometimes cast without a footer. They were also cast against the earth as the opposite side "form".

To check the nature of yours I would use a masonry bit and hammer drill to drill a hole into the foundation at some point maybe a foot above the floor. If you drill in perhaps 4" and are still in solid material you have a cast foundation. I would drill a few holes as even hollow block do have solid webs joining the opposite faces of the block and you want to make sure you are not just drilling into one of the solid spots.

Not having a footer is not the best situation but if the walls were cast with integrity and seem to be reasonably plumb and are not showing signs of cracking or settling, I guess I would not get too worried. It more or less depends on the nature of the soil beneath the foundation.

If you start doing any excavating along the wall edge in the basement I would not be undermining the wall. Also, keep in mind that if there is no footer then the concrete floor is helping to prevent lateral movement of the foundation due to soil pressure against the wall.

This is a situation where a first hand inspection by a veteran mason would be wise choice.
 
  #3  
Old 02-07-14, 07:14 PM
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Thanks for the quick response. I seem to remember drilling in to the wall in the past and it being hollow inside but I may be wrong or that may have been higher up. Is it possible that they would lay block directly in the dirt like that right below the floor? I was certainly hoping this project would be a little more straight forward but now I'm not sure how I would proceed. If I can get my hand underneath I guess there is no footer. If that is the case how deep should I go and should I stay a certain distance from the wall.
 
  #4  
Old 02-07-14, 07:44 PM
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I really think you need a professional to get a first hand look.

The part I didn't tell you about is that I know of a somewhat similar case where the floor was removed from a basement to make room for a new floor. There was no footer and when the wall was poured against the earth as the outer form...they were neglectful of issues. The bottom of the wall in many places was 6" thick and the top was 8" thick. After the floor was removed there was a heavy rainstorm and 40' of foundation fell into the basement. Not pretty. And insurance does not cover foundations.

Go to a concrete or block supply house and ask for a couple good references to review the project. If they charge, it will be money well spent.
 
  #5  
Old 02-07-14, 07:59 PM
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OK thank for the advice. Much appreciated.
 
  #6  
Old 02-08-14, 03:09 AM
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Just to add, my in-laws in NJ had a perimeter drain system installed that looked like clam shell trim around the outside edge that caught and directed all leakage into two corner sumps. As I recall it was barely cut into the floor, probably because it was easier in their case. But for you it would be less destructive of the support. Essentially it builds the drain path above the slab.

Bud
 
  #7  
Old 02-08-14, 06:00 AM
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Yea I thought about that but Id really prefer to do it the right way if at all possible.
 
  #8  
Old 02-09-14, 10:11 AM
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I had a friend who is a contractor look at the situation and he suggested It would be safer to do it from the outside. My basement is only 4 feet below grade so it shouldn't be that big of a deal for me to rent an excavator. I figure that way I'd be able to water proof the foundation and run some drainage pipe at the base of the wall. Anyone have any suggestions in regard to that and there being no footing?
 
  #9  
Old 02-09-14, 05:40 PM
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aa. I don't know the dimensions of your house but if you are going to excavate the exterior you might want to proceed in stages as in not doing the entire length of a side at one time. Perhaps excavate, clean the surface, waterproof and add drain tile to alternate sides for half the length and get them back filled partway before excavating the remainder.

Where do you anticipate leading the water to that makes it into the drain system?
Is there a point that gives you the ability to run to daylight (open end drain at a lower elevation than the lowest point around the foundation)? If you run into the basement and put in a sump pit you might want to use two locations.

Of course, you won't know what the outside of the foundation is like until you excavate but you have to examine the various types of waterproofing agents or membranes available. Or you may start checking out a spray applied material like Rub-R--Wall. You will probably also want to include some exterior insulation such as Dow Strofoam Xps board.

Perhaps talk to the local code official about what the local approach is to waterproofing and insulating.
 
  #10  
Old 02-10-14, 07:58 AM
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Yea my friend suggested the same. Doing it in sections .The longest wall is 45 to 50 feet. The back is about 25 feet separated in two sections by a walk out door. The other side is the same but separated in two by stairs and a side entrance and the front is a non factor due to a large porch that keeps the water away from the basement wall. I was planning to have some sort of setup with a sump pit.
 
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