Thread: Concrete Block Garage Foundation Cracks

Saw this yesterday in a 17 year old house. The garage foundation walls are concrete block with a fair bit if cracking and separation showing up on the exterior walls. The view of the foundation walls inside the garage showed open cells from the top of the foundation down to the bottom. The last pic I posted here is of daylight from the exterior showing through the foundation wall.

I don't often get to see down into the cells of concrete block walls and thought the open cells maybe should have had reinforcing rebar inside the cells and the cells filled.

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Pic #2 of the downspout is most likely the culprit. Roof runoff saturating and compacting the soil at the foundation causing corner of building to settle. If the soil is not unusual (expansive or loamy), correct saturation problem and foundation should stabilize.

Doubt any drainage plane, building paper behind that vinyl siding either, no drip or flashing seen anywhere. No cap, flashing or transition under sill. See above grade parging, but at and above grade see no evidence of damp proofing, water proofing membrane, tar, etc. (overfill, bad fill, grade). See no extension or even splash block for downspout.

How to diagnose foundation cracks: Concrete block or "cinder block" or concrete masonry unit (CMU) foundation inspection procedures and the diagnosis of cracks, bulges, leaning, bowing, and settlement in concrete block foundations and building walls

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Probably combination of shallow footing(s) appears garage outside corner, copious amounts of water dumped at corner, and freezing.

Nick,

Here in CA, you can't build with unreinforced masonry. (Easy formula: Ground moves, blocks fall down.)

In areas that do not have seismic movement, requirements have traditionally been different. But, since I don't inspect outside of CA, I don't know the requirements. I seem to recall at one point in AZ, you only needed to have reinforcing and solid grout in 1 out of 3 cells. I don't know if this has changed (or if it was even correct, just something I was told years ago).

Bob is probably correct about drainage. Drainage and freeze/thaw can really cause problems with a foundation. However, correcting drainage will not fix the foundation. If you are not sure what is required for block walls in your area, defer to a foundation contractor. If you are sure what is required for block walls, defer to a foundation contractor.

Thanks guys. Grading was suspect around the house and the downspouts were exhausting too close to the exterior walls all the way around the exterior which I did mention to my client and also in the report. I told him correcting the grading and extending the downspouts might be all that is needed but he would be best getting the cracks and damaged areas (horizontal cracks on interior basement walls too) serviced by an SE or foundation professional.

While in MN I saw this type of problem all the time. There, every couple of course of block was supposed to have a ladder type mesh reinforcement but it didn't help if the ground around the foundation got saturated and settled carrying the blocks with it. No core filling was required at that time.

From the many hundreds of stair step cracked foundations I observed, particularly at corners of garages where the wall was weak due to the vehicle door opening, it became pretty standard to recommend the client correct drainage, caulk the crack to keep out weather and critters and monitor the cracks over time for any further movement. I never had anyone come back with a complaint later on.

This recommendation was given only if there were no other unusual circumstances going on such as unstable soil that was obvious to me visually on site, or very large cracks (seeing daylight through a stair step crack was not uncommon), or if the block displacement was horizontal as well as vertical.

Your recommendation falls into the realm of how comfortable you are with what you choose to advise the client on a thing like that. I came to believe that to recommend a SE was not necessary and got the client unduly worried. But that was just me after observing many, many situations just like that and drawing conclusions from the experiences in my particular neck of the woods.

There were also horizontal cracks on the concrete block foundation walls in the basement Bob. The garage wasn't the only issue. I do feel fairly certain that grading and drainage are the culprits at work here and correcting those issues may very likely be the end of things. But I don't want to be the one to tell the buyer "those cracks in the foundation wall don't need repair" when there is a real possibility he could end up getting an SE who says the foundation does need repairs.

I'm not worried about whether or not the recommendation for an SE worries the client. I'm worried getting pinned with repair bills if I recommend no action and he buys the house and finds out repairs are needed.

Originally Posted by Gunnar Alquist

Here in CA, you can't build with unreinforced masonry.

Same here, most crawl spaces are pier and curtain walls but if you use block for piers or a foundation wall it must be filled.

I seem to recall at one point in AZ, you only needed to have reinforcing and solid grout in 1 out of 3 cells. I don't know if this has changed (or if it was even correct, just something I was told years ago).

This would make sense if for no other reason than a way to secure the foundation straps.

Originally Posted by Nick Ostrowski

I'm worried getting pinned with repair bills if I recommend no action and he buys the house and finds out repairs are needed.

Yeah, that's what I meant with the idea of how comfortable you may be with your recommendation to the client. Evey one has their own tolerance for pain.

Part of it for me Bob is also knowing that opinions on what is and isn't needed will vary on the part of whatever professionals would come in after me to look at the foundation. If I say "not a problem" but the client buys the house based on my recommendation of "not a problem" but wants after living in the house a few months wants a 2nd opinion, I don't know what the SE is going to say. One SE may recommend nothing more than correction of grading and drainage and sealing the cracks. Another may recommend $5,000+ in repairs at which point I would surely get the call "Nick you said it wasn't a problem. Now I need foundation repair". Is this what you meant by tolerance for pain?

I only have control of what I do and say. What the other guys say is another matter entirely. I've talked to electricians about knob and tube wiring where one says it can be OK and another will recommend rewiring the entire house as soon as they hear it has K&T, sight unseen. Opinions vary greatly as to what is and isn't needed.

Yeah Nick, that about sums it up. Nothing wrong with your thought process. We all have that monkey on our backs (or is it an SE? Ha!) always poking us to "be careful and defer that problem". Who knows what will happen! When do we listen? When do we not? Each one has their own tolerance.

Beginning with no tolerance for pain, a home inspector would defer EVERYTHING they see in an attempt to cover their butt completely against law suits or insurance claims. Of course this is neither practical nor good business but it's the beginning point for our thought train.

From that point on the inspector draws on their knowledge and experience to make a determination whether to defer findings or not. How far along the "I-am-not-sure-and-don't-want-to-get-stuck-or-sued" path we choose to travel is based on many things...all personal. Sometimes even involving what we think some one else might have to say about it.

I'm sure everyone on the Forum has at one time or another made the decision that although something they find during an inspection may not be quite right it is still O.K. for what-ever reason and thus not deferred it or maybe not even reported it. They have tapped into their personal "tolerance for pain" system. After all, they could be wrong and get sued or worse.

Perhaps a home inspector knows for a fact that a problem needs attention by a licensed contractor and defers it. No problem, no pain. Theoretically, the more the HI learns and knows the more accurate the call to defer should be thus greatly reducing the "tolerance for pain" question. However, after all the years I have been a professional inspector there are still times I find myself having to make a "tolerance for pain" decision. I don't think it ever goes away completely!

As an aside, since your original post was merely an observation of the situation with the block wall, not really a direct question for the board, the direction the thread has taken is fascinating and one of the reasons I read the Forum regularly. We have to thank Brian for keeping his Forum going! Remember to send him a couple of bucks to keep him going you all!

Nick

In my opinion Bob gave you good advice...poor drainage and saturated soil causing poor foundation support. That foundation looks like it was thrown together by the homeowner and his buddies for a case of beer. To do a full engineering evaluation would probably not be cost effective on that structure.


Randy mayo, P.E.
RLM & Associates, LLC

Randy, I see you have a P.E. designation in your signature. What would be your recommendation for repairs if any based on the information I've provided along with the pics?

Nick

From your pictures it looks like the overall stability of the structure is fine. I would suggest regrading around the building to drain the water away and extend the downspouts or pipe the water away from the building. Once the moisture content of the soil under the building dries up some the foundation should stabilize. I would measure and mark some of the cracks and chart them over time to monitor the movement. It could take 6 to 12 months depending on the depth and type of soils you have. After the movement stops then I would look at any repair work structural or cosmetic.

Thanks for the info Randy. And it makes sense. The only problem is there's nothing that can be done now and it will require the buyer to live in the house 6-12 months before they will know if repairs are needed. I'm not saying that is your fault at all. It's just for me to recommend no action now when there is the possibility (maybe a small possibility) that repairs might be needed within a year leaves me biting my nails for the next year hoping I don't hear from the client.

There were other horizontal cracks on the interior basement walls which I called out at the inspection and in the report so there is more than just the garage for an SE to evaluate. And I'll sleep better too.

Nick

With open cells, how was the garage walls secured to the foundation?

Originally Posted by chris mcintyre

Same here, most crawl spaces are pier and curtain walls but if you use block for piers or a foundation wall it must be filled.





This would make sense if for no other reason than a way to secure the foundation straps.

In Michigan, cores are not required to by filled unless you have an unbalanced soil load on the wall. Even then it depends on the soil type and height and size of wall. Normally doesn't even start until you get over 4' of backfill.