Question from Newbie re: break in corner of poured concrete foundation

[Lisa Masciantonio]

Hi folks,

Just to clarify, we do not have a french drain in our basement. We have a sump pump only. There is efflorescence along the lowest part of the wall in the basement (along several feet). I have also seen evidence of water coming in through a few ties holes (that is what I believe they are called) in the basement. We have had some issues with slight standing water (usually after a period of days with very heavy rain). I asked the SE if this would amount to a structural issuse and he said no. He did recommend putting extensions on our downspouts, and we did do that.

I'm sure the grading of the land is not helping matters. Further, I have no idea if the breakage in the corners of the foundation is water related or not.

I do intend to contact David, as suggested above, to have a foundation repair specialist come to the house. My concern is that we are not rich people and I can only hope that whoever comes to the house is honest about what needs to be done, as opposed to lining pockets. Unfortunately, we have been burned one too many times in the past.

[Robert J. OConnor]

Not all houses are built with drainage systems (exterior foundation drains or interior french drains), and current US construction standards only require foundation drains if there are poor soil conditions. Some designers, including me, believe that installing foundation drains with good soil conditions actually draws water towards foundations. Local construction in your area may differ.

All basements will leak a little. But I just didn't see any reference to basement water penetration problems or french drains for the original poster.

[ROBERT V. YOUNG]

Thankful Mr. O'Connor for catching my 2 mistakes. I am in Canada. I am using. Montreal preferences which I will make note next time.
Thank you.

[ROBERT V. YOUNG]

Originally Posted by roconnor

Not all houses are built with drainage systems (exterior foundation drains or interior french drains), and current US construction standards only require foundation drains if there are poor soil conditions. Some designers, including me, believe that installing foundation drains with good soil conditions actually draws water towards foundations. Local construction in your area may differ.

All basements will leak a little. But I just didn't see any reference to basement water penetration problems or french drains for the original poster.

This is new and a rarity in Montreal from my knowledge.
Interior basement drainage ( under slab ) from hydrostatic pressure.
It is catching on in the foundation industry this year. Cheaper than full exterior drainage.I see more advertisement.
I wonder about the exterior lateral forced and wet foundation though.
Can discus that on another thread.
I bumped into interior basement drainage 2 years year ago doing a estimate for window sills. ( still doing HI studies at the time although not as intense as the past 20 months.
The inspector conclusions where questionable for the recommendation.
They ripped out 60 thousand dollars worth of 5/4 classic oak panel to find a leak.
My jaw hit the floor.
The home owner used the same agent and inspector all 5 times for all 5 homers in the past 7 years..
PS: all homes had problems. The owner was forthcoming and naive..
My jaw hit the floor.
PS, PS. They have money.
So does the agent and is well known for selling property.
At it for 25 plus years.
That's why I am here Mr.O'conner.
Your help helps me and I in-turn I might help someone.
Thanks really.

[Randy L. Mayo, PE]

Lisa

Does your foundation corner look like the first two attached photos?

If, so this is caused by expansion of the brick veneer. Brick expands due to heat and/or moisture but the concrete foundation doesn't expand as much. This difference builds up stress in the concrete foundation because the brick is basically glued to the foundation with mortar. I ran a computer simulation (third picture) which shows the stress build up at the corner of the concrete foundation shown in red. Concrete typically can withstand a large load in compression, for example 3000 psi. However concrete is weak in tension, typically the tension strength is only 10% of the compression strength. So in this example 300 psi, which is why the corner of the foundation is easily broke off by the forces induced by the brick expansion.

[ROBERT V. YOUNG]

Nice one Randy.

[Lisa Masciantonio]

Hi Randy,

The shape of the largest break looks very similar to your photo, however, our home does not have a concrete veneer. It is clapboard siding.

I also responded earlier to the inquiries about our basement water issues above. Again, not sure if it is related, but we have had ongoing damp basement issues. Details are in a previous post.

[ROBERT V. YOUNG]

Lisa Randy is correct in his assumption of expansion.
The brick veneer would be more conclusive though.
The sill plate to the home will expand and the home ( residential building or unit ) will expand.

Just one of many assumptions and what I have observed.
I have seen poor building practices and techniques from many foundation installers.
It has to be finished when it stops bleeding, ( slang: the cream has come to the top and) or is thumb tight ) cured to perform a finish.
When you finish a foundation pour, you hand finish the sill landing or top of the wall with a bull float.
You try to make it as level as possible.
Easier with a string.
If you draw the concrete to the corners when doing your finish it may leave them higher than the rest of the plain.
The finisher must maintain level.
High spots will have excess loads placed on them.
Even the wrong bull float material can effect concrete.
Wood and magnesium are the preferred in Montreal.
Metal or steel will degrade the finish on exterior applications.
Air-entrained, and I can go on.

#1: not finished right.
Finished the concrete to the corners leaving them high.
#2" Expansion of the unit. Sill plate.
Proper finish for PDF.
Click on the PDF file.
I have seen many foundation installers make many mistakes.
Just ideas. Try to hypothesize on the problem.
Wood and expansion and contraction.
http://www.ehow.com/how-does_4742977...-contract.html
Now add your humid foundation.
All the elements are given to you to draw a hypothesis.
#1: I will say to look into your land or property grading.
That would be my first step or recommendation, grading.
#2: My second recommendation is to see if your sill plate is flashed properly.
Is your siding flashed?
If there where brick, the expansion would be partial to my hypothesis.
Is the sill getting moisture.
I forgot where you live.
Is there a thaw and freeze cycle?
That can exaggerate a problem.
Good luck.