Basement Cement Block Wall Movement

3544 Views 13 Replies 7 Participants Last post by Guywithskills, Jan 5, 2013

Iowa_Mike

Discussion Starter · Dec 26, 2012

Just visited my elderly folks this morning, and found a surprise in their basement. Apparently years ago they had wall anchors installed in an attempt to mitigate cracking/bowing in their cement block basement wall. They were supposed to tighten the anchors at intervals to minimize damage to the basement walls, but I'm guessing that hasn't happened. I noticed this morning that along an ~8' stretch, the entire basement wall has moved horizontally inward an inch except for the very bottom row of cement block which has remained stationary. So there is literally a one inch offset from the bottom row of cement blocks and the entire rest of the wall. Additionally, there are no cracks in any blocks themselves but plenty of stair-stepped cracks in the mortar joints (most cracks are minimal width, but a few are 1/8"-1/4").

Aside from calling a foundation expert to assess, what are recommended options in this case? Will continuing to periodically tighten the wall anchors be sufficient? Does the house need to be jacked up and a portion or all of the basement wall need to be rebuilt? Because they're elderly and on a fixed budget, I'm looking for advice based on what will suffice for the next 5 years or so and is cost efficient in the short term.

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jomama45

· #2 · Dec 26, 2012

What happened to the walls is what we refer to as "shear" in the trade. It typically takes place between the first & second courses, as the first course is locked in place by the basement floor.

Nearly impossible to tell how severe it is over the web, or w/o an onsight inspection. Personally, I'd suggest talking with a structural engineer who specializes in foundation issues, as they will generally give a good, non-biased report with scope of repair. Calling in a foundation repair company may seem like the cheaper, more effective approach, but most will attempt to scare you into having the work done immediately.

As for the tie-backs, tightening them will likely do nothing at this point, as it sounds like the anchors/deadman outside have already started moving.......

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stadry

· #3 · Dec 27, 2012 (Edited)

deadman or screw anchors have probably moved so its resolution is unlikely w/o ext excavation for nec/rqd reprs,,, stair-step crks aren't unexpected as wall's moved,,, jack & rebld probably best as tightening anchor bolts is like trying to move ext soil back to original position,,, in your folk's home, the ext soil's lateral pressure has overcome the resistance of 1 block mortared to the 1 below - lateral soil pressure has overcome the hollow block wall's resistance to same

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federer

· #4 · Dec 30, 2012

you guys are experts obviously, but is this a crazy idea: just build a new block wall on the inside? you would lose a few feet of space but that's cost effective right?

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joecaption

· #5 · Dec 30, 2012

If you did that the old wall would still be moving and could collapes, water can start coming in behind the new wall, there would be no footing under the wall so it would not support the weight without cracking the slab, there would be no support under the outside wall where it needs to be.

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federer

· #6 · Dec 30, 2012

joecaption said:
If you did that the old wall would still be moving and could collapes, water can start coming in behind the new wall, there would be no footing under the wall so it would not support the weight without cracking the slab, there would be no support under the outside wall where it needs to be.

good point! i am stupid. what if you build it right against the old wall to slow down its movement enough with the weight? i guess you can put down those rubber/poly sheets between the two walls so if the old one does collapse eventually water cant come through but will be able to rest against the new wall.

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stadry

· #7 · Dec 30, 2012

don't be so hard on yourself, idiot :laughing: seriously, its an idea tried many times however even cast-in-place concrete walls normally can't resist the soil's lateral pressure & often crack,,, the ONLY time 1 can wtrproof a wall is when the exterior is available - anything after that is wtr management :yes:.

another point often misunderstood - there's no way to prevent water from entering bsmt's UNLESS the issue's resolved on the exterior :thumbsup: there are instances when a leaking wall/floor can be stopped however that's only on the surface - wtr's still penetrating to the depth of the wall/floor - we just can't 'SEE' it nor its damage ,,, several years ago, a bsmt wall imploded/collapsed from yrs of soil pressure & leaking wtr,,, walls were sparkling white from many coats of paint & obsessive care but never thought about what was happening outside :no:

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federer

· #8 · Dec 31, 2012

itsreallyconc said:
don't be so hard on yourself, idiot :laughing: seriously, its an idea tried many times however even cast-in-place concrete walls normally can't resist the soil's lateral pressure & often crack,,, the ONLY time 1 can wtrproof a wall is when the exterior is available - anything after that is wtr management :yes:.

another point often misunderstood - there's no way to prevent water from entering bsmt's UNLESS the issue's resolved on the exterior :thumbsup: there are instances when a leaking wall/floor can be stopped however that's only on the surface - wtr's still penetrating to the depth of the wall/floor - we just can't 'SEE' it nor its damage ,,, several years ago, a bsmt wall imploded/collapsed from yrs of soil pressure & leaking wtr,,, walls were sparkling white from many coats of paint & obsessive care but never thought about what was happening outside :no:

hey man! havent seen you in a long while since you usually hang out in this section of the forum. thanks for the info! so water always wins. i have learned the hard way myself

guess that makes me idiot twice!

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stadry

· #9 · Dec 31, 2012

you, too :thumbsup: had a biz to sell prior to obama-yo-mama's taxes

kickin' in :thumbup: IF you/your parents're considering its 'sell time', there is another, less costly, method - build a retaining wall INSIDE the home's bsmt wall... managing the water inside AND the grades outside would still be of prime importance in resolving this issue !

we're all the same - some things we ALL all learn the hard way :whistling2:

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jomama45

· #10 · Dec 31, 2012

federer said:
good point! i am stupid. what if you build it right against the old wall to slow down its movement enough with the weight? i guess you can put down those rubber/poly sheets between the two walls so if the old one does collapse eventually water cant come through but will be able to rest against the new wall.

Typically, if you're going to build a wall with the same dimensions, it's just as constructive to replace the existing wall. Sure, you have to tear-out & excavate the exterior, but you don't have to cut out floor and install a new footing. Also, you get a FAR better finished product, that will last a lifetime if constructed correctly...........

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beentheredoneit

· #11 · Dec 31, 2012

wall anchored

is this the same thing as street creep?

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stadry

· #12 · Dec 31, 2012

where you are ? we sure have a ' street creep ' in our n-hood :laughing:

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federer

· #13 · Jan 2, 2013

itsreallyconc said:
you, too :thumbsup: had a biz to sell prior to obama-yo-mama's taxes kickin' in :thumbup: IF you/your parents're considering its 'sell time', there is another, less costly, method - build a retaining wall INSIDE the home's bsmt wall... managing the water inside AND the grades outside would still be of prime importance in resolving this issue !

we're all the same - some things we ALL all learn the hard way :whistling2:

so how does a retaining wall work inside? i thought they were used to level out a steep slope and prevent soil erosion, etc

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Guywithskills

· #14 · Jan 5, 2013

Another option, the stepping you described is not high risk, the issue is water. Bentonite berm, poor a 3 ft walk around the house to shed water away from foundation, do not know where your water table is. If it is high, the issue is not rain water rather ground water. Here in AZ, it is rain, since the water table is more than 600ft down. What happens in colder country, water seeps against foundation in winter, freezes and pushes it in. Once again, keeping water out is the answer. Had a customer on a house I built dig a trench through the 30" wide berm that protected his basement wall and did not rebuild, they called saying they had leaks. When I inspected,they had irrigation and water ran in and nearly made a mote around the basement wall. Rebuilt the berm, leaks stopped. The wall was sealed with asphalt emuslion 25 yrs ago. today, a better solution is Elastomeric with fabric or fiber, It flexes and stretches. Ideally, Seal wall, place a barrier to protect seal, back fill with a semi porous aggregate with the top of drain tiles at the bottom a minimum of a foot below the basement floor and sump pump out from the drain tile. Outside and at the top of the backfilled area is bermed from house with a clay back fill last 2 ft or pour a walk around perimeter to shed water away from foundation. Never plant up against the house. Bad form to have landscape that puts water against the house. People do this all the time.

Otherwise, dig out perimeter and do it all as described, involved, tedious and will take some cost.

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