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Concrete Foundation Spalling Concerns?


irwinsc
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Our house is a 1922 Craftsman that we bought 2 years ago with serious spalling in the basement around the window frames. The spalling runs horizontal, along what appears to be a seam in the foundation (between the cinder blocks and bottom foundation. We've never experienced any major water events, or even minor events for that matter, but can see evidence of years of wetness. Last summer we took some steps to "waterproof" and now want to fix the spalling in the basement both for concerns of structural damage and for appearance /resale.

Can anyone determine from these pictures if we've got structural damage on our hands or what steps we should take to make this look better?

Any help is appreciated!

More info... :-)

We excavated around the foundation last summer and noticed some cracks. We had someone pin-tuck (?) the foundation and pour cement around the foundation (about 10") to stabilize the foundation. We also added gutters and some drainage away from the house.

The spalling is at the horizontal seam (as seen in the pictures) across about 80% of the basement. It is most severe under the windows and least severe in the front of the house where the the drainage is the best.

It has been raining for 2 days and noticed dampness in one spot that seems to be the worst (right under the outdoor faucet, which is currently turned "off" as it is still cold).

Apparently, the house is lower than a large school field that drains into our back yard (where the damage is the worst). We've never seen standing water in our yard nor would I consider our yard "low", but it is clearly lower than the school. I'll try to get pictures of the yard tomorrow.

I'm mostly concerned about the structural integrity of the foundation. From the pictures, would you all suggest a contractor or engineer come in, or does it seem to just need some patching and paint?

Thanks again!

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I can almost see your house from my office door, but can't tell you squat from the photos! What did your inspector say at the inspection? What part of town are you in? etc.. Any answers would just be a guess at this point.

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Can you take some more photos from a wider angle so we can see the whole corner or wall of the basement. It's hard to tell from the photos exactly what was done. Block was added on top of a poured foundation but can't see enoough of the whole room.

I added more to my original post with more info...and some more photos here.

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It really looks to me that the lower foundation was poured, or mixed I should say because, it looks like it was mixed in a potable cment mixer, the mix was poor with too much sand and gravel. Then the block was added on top. The resulting joint has leaked over the years and caused the poured concrete to deteriorate. Adding a bonding agent and resurfacing may help as far as appearance but you may have to attack the exterior below grade to actually stop water from entering. I would get a lisenced mason over there to take a look.

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Is the soil in your area high in alkaline content?

Can you take some more photos from a wider angle so we can see the whole corner or wall of the basement. It's hard to tell from the photos exactly what was done. Block was added on top of a poured foundation but can't see enoough of the whole room.

I added more to my original post with more info...and some more photos here.

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tn_2009420234153_Spalling%2012.jpg

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Hi,

I wish I could see that in person. It kind of looks like foundations that I've seen around here the began as crawlspaces and then later became basements. They prop 'em up, pour mud under them and then bust off the inner ear of the footer, leaving a jagged edge where the original flooter used to be. Did you dig down on the outside of that thing with a long screwdriver or bar to see if there's a footer ear projecting from the other side of that wall below grade?

ONE TEAM - ONE FIGHT!!!

Mike

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That type of foundation was really popular around here from 1900 to 1930. The concrete portion ends right at finish grade so that all you see from outside is the block. The only one I've seen that wasn't wet and spalling like the IP had so much water under the slab that anything placed on the floor would draw the water up through the slab.

My neighbor replaced their foundation a few years ago, and the new one was built exactly like this, presumably so there would be room to remove all the steel and cribbing from under the house.

irwinsc, you need to improve exterior drainage to keep the foundation dry, then have the block repaired, then go over the bad areas with a fiber reinforced patch and a bonding agent. Perhaps most important, document all your repairs and improvements. When you sell, the HI will notice the repairs and good documentation will help resolve any questions.

Tom

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  • 1 month later...

I am a structural engineer and home inspector. Its hard to say too much without seeing the overall picture. Grading is probably a big part of the cause. The block walls are typically more porous than the concrete walls and when water gets into the block cores it sits there. The concrete is probably a very low strength mix. It the walls are plumb and have not bowed along their length the walls are probably reasonably sound because it appears that the concrete wall is a bit wider than the block wall so the block wall still appears to be sitting on a stable base. If this is not what I am seeing and the concrete below the block is deteriorated that would not be good. Patching deteriorated concrete is typically not easy because nothing will stick to it. If you use wire lath on the inside to help adhere the patch then you will trap more water. It sounds like the grade level at about at the top of the concrete. that is good because there would be less pressure on the walls. You could have someone waterproof the exterior side of the foundation walls from about grade level to somewhere below the joint between the block and concrete. Also, grade the surface away from the foundation at about 1 inch per foot for approximately 5 to 10 feet away from the walls. Grading should be done with a soil that has a high clay content. Topsoil or much can be placed on top once the grading is done.

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  • 3 weeks later...

I agree with MJR as it looks like a bad concrete mix coupled with exterior moisture infiltration. If there's any steel rebar in that foundation wall it will only get worse, but by the age of the building I doubt they used steel rebar? Start by checking the exterior grade and seeing if you don't have ponding against that section of foundation in wet weather.

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  • 3 weeks later...

The spalling is water vapour penetrating through the old concrete, probably through a cold joint. Perhaps your drainage tile isn't working and the hydrostatic pressure is seeping through (Concrete in the '20s isn't notable for good mix either) First things first, get the water away from the exterior foundation walls. If your walls are plumb, you shouldn't worry about structural failure. (90yrs=1/2" deterioration on 12" concrete wall... so 1"every 180 years.. hmm come and see me in 500 years);)

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