Horizontal and vertical cracks in CMU foundation


I’m a first time home buyer and I recently had my first inspection on a 1962 rambler. The house has a relatively flat front yard but is built on a down slope with walkout basement.

On the right side of the basement the inspector noticed an issue with the CMU wall. The concrete blocks had high moisture levels on his meter and some of the horizontal mortar was soft, missing, and crumbling out.


The grade is relatively flat on this side of the house, but gets steeper toward the back (right side of the following picture)


There are additional vertical cracks on the front foundation which have a layer of cement over it. Not sure why the side foundation walls don’t have cement on top…



The rear/walkout side of the basement is finished, so there’s no telling what the walls look like, although I didn’t see any cracks on the the left side of the foundation.

The house also has a couple steel ibeams running from front to back and one ibeam running partially from the middle to the side with the water damaged foundation wall. My father thought this was suspicious and not indicative of the time frame the house was built. For example, this ibeam doesn’t extend too far into the concrete due to the floor joist behind.


Here is another ibeam from front to back.


How concerned should I be? The inspector recommended I have a structural engineer inspect the foundation, but that the problems weren’t that egregious. I’m pretty conservative, so I’d like to be 99% sure, so I’m doing all the research I can. Any advice would be greatly appreciated. Thanks!

I do evaluations as part of my business and can tell you nobody on this board (or elsewhere on the web) can to do an adequate evaluation from photos and a description.

Follow your home inspectors advice and have an engineer take a look at it.

Good luck … :wink:

I second Robert. If the inspector you felt comfortable enough with to hire is advising you that you should get an engineer to look at a problem, you should follow his advice.

Also, while it is difficult to adequately evaluate from just a few photos (and my eyes may be playing tricks on me), it appears from the photo with the radio that termites might be an issue. Those brown stains look like the remains of shelter tubes.


If you need a third opinion I agree with Robert and Darren. I am not a big fan of CMU foundation walls. In all the different types of basement foundations I have inspected my ranking from worst to best are:

  • Unreinforced hollow CMU block walls
  • Unreinforced concrete filled CMU block walls
  • Unreinforced poured concrete walls
  • Reinforced concrete filled CMU block walls
  • Reinforced concrete walls

If you hire a structural engineer I recommend you use one that specializes in residential type engineering/foundations and has done several inspections.

I agree Randy, CMU sucks.
I’ve always said that concrete masonry units were never intended to be installed in the ground as retaining walls for a foundation.
Even an engineer will have difficult time on site to evaluate if reinforces, grouted or improper sized footing causing movement.
Good luck. :slight_smile:

Thanks for all the advice. I guess my next step is to hire a structural engineer, which is what I planned to do. Should they be able to identify signs of termites though? I now feel like I’m going to have to hire a bunch of specialists (and spend a lot of money) before feeling comfortable with the house. I suppose this is how it is to be a homeowner :slight_smile:


In the long run it will be far cheaper to hire a few specialist now than buy a house with serious foundation problems and possibly termite damage.

Pay a few hundred dollors now or pay thousands later. :slight_smile:

Just out of curiosity Brandon is this property some fantastic bargain? There is a lot wrong here given the apparent termite evidence, structural settlement and moisture conditions.

I am not advising that you should keep on looking but you could cut your expenses on this property now by passing on it. That is your choice entirely and I commend you for your due diligence in researching the opinions of others.

The property came on the market at $440k and was dropped to $400k after about 2 months. We signed a contract for $380k net. I think the seller is anxious to get rid of the property. I really like the house neighborhood, etc., but the foundation is clearly an issue due to the water.

I had a foundation guy come to check out the place for a free evaluation. He has a background in geology and seemed pretty knowledgeable. He’s not a PE or structural engineer, however. I was referred to him by a friend of mine who does general contracting, but he hasn’t personally worked with him yet. At any rate, he suspects that perhaps at one point the foundation where the mortar is deteriorating along a horizontal was replaced. The pattern of CMUs and brick (he said contractors back in the day used bricks as termite barriers periodically between CMU courses) was not the same. In fact there were only CMUs and they were more square in shape than the rectangular ones elsewhere. He checked the foundation wall with a level and discovered that it’s about 1" bowed in at the worst. Here’s a diagram of the foundation outline and where the various ground slopes are. Neighboring house downspout dumps right near the house, unfortunately (blue line is approximate path of water).


At the end of the day, he recommended that were I to go ahead with purchase and get work done that I put in an interior trench along the foundation wall down to the slab. He said it would cost around $5-6k and that digging the trench around the outside would cost more because the stoop, AC, and such would have to be moved. He recommended putting in an ibeam with columns to help supporting the bowed wall or perhaps using carbon fiber mesh, but the latter would be less effective long term.

Beyond my conprehension why anyone would build a $200,000 house on a block foundation, and not provide the proper underdrainage, water proofing and proper backfill material to compensate for the weakness of lateral pressures. Dam!! :):wink:

Are there any pilasters along the foundation?


Trenching on the inside is usually an attempt to treat the symptom and not the problem. Horizontal cracks and bowing of a CMU basement wall are typically caused by water and/or soils that swell when wet. The deteriorated mortar may have been a crack due to bowing of the wall that was later filled. Corrective action could involve in some grading work, curtain drains, new drain tile on the outside and possibly some engineered tie-backs through the wall. If the CMU blocks are hollow you basically have an interstate highway for termites to enter unseen. You could easily spend $50,000 on the wall itself plus extra for any termite issues. Keep in mind you may someday want to sell this house an the list of buyers interested in a house with previous foundation problems is pretty short.

Exactly Randy. :slight_smile:

Quite a few trees on-around property huh.
And this is in Fairfax VA?
…scroll down to, Basement Wall Damage…read cause and resolution.

Underground roots can cause problems as well,for instance…see photo’s 3,4 etc

When the cause of a wall bowing in and cracks are due in part/all to lateral soil pressure or roots or a porch footing etc then installing any jerk off INTERIOR SYSTEM and beams,carbon fiber crap etc does NOT
remove,reduce,relieve these causes…AND does NOT waterproof-repair the EXTERIOR cracks,joints like this…

Here…another inside system and beams were installed,thousands $$$ spent and…basement still leaks,cracks widening etc because somebody who ONLY installs inside systems didn’t identify the problems/causes correctly and just wanted to sell the one shtthead thing they do…
Help my dumb azz with this would ya plz! :mrgreen:

Eh, if a g damn TREE fell on your ROOF and CAUSED damage to the roof which subsequently led to WATER entering the stupid roof would you…
LEAVE the tree on the roof,not repair the damage and INSTEAD go up in the ATTIC and say,maybe install some beams,carbon fiber straps and install a sump pump and some drain tiles!!!

Frank Zappa and George Carlin…“Can’t you just sense how eager the rest of the universe is for US to show up”


I am completely amazed sometimes how people try to save a few hundred bucks on what is for most the single biggest investment they will ever make in their life costing hundreds of thousands of dollars … :roll:

Agreed for the 3rd time. :wink:

I agree with this also!:smiley:

According to my agent, the seller believes there is no problem with water or the foundation, although I don’t believe they’ve been to the house yet to see the area of concern. Based on the buildup of efflorescence on the floor, I’m guessing they hadn’t been to that part of the basement in years. In fact, they probably could have parged the wall and I would have been none the wiser.

As for the block masonry, most of the older houses in this area appear to use it. In this early 1960s neighborhood, the developer did use brick masonry below the ibeam supports. I was told this provides better compressive strength.

I’m going to get another quote from a basement company, just to see how they compare to the other guy’s recommendations. Of course, I would prefer the exterior drain tile and excavation. I don’t think the seller will move downward on the price though, so I’m probably going to have to punt at the end of the day.

Thanks for all the help gents. This experience was very enlightening. I hope it prepares me better for my next home inspection :slight_smile:

Did you really expect a different response … :wink:

Your just not following what your home inspector and others here on the board have tried to tell you … ](*,) … you need an independent evaluation, not another estimate.

In the end it’s your decision, and good luck with the house if you purchase it.