Retaining Wall

[Ronald G. Chorey II]

Have this home, it was built in 2006. It is a zero lot line home. There is a foundation wall that appears will be filled at some point in the future. I have not seen this before. I think the foundation wall is built out of block that has been covered with a cementatious type product. My question is shouldn't the fill be gravel for proper drainage? There are a few cracks, should I call out for a structural engineer? And shouldn't the exterior wall itself be coated with something so that water can not eventually get through? Any help would be appreciated.

[Brian E. Kelly]

I for one do not see a retaining wall for to me that implies that the wall is 1. holding back earth and 2. engineered.

I would call out the step cracks in the block wall and reccomend sealing and monitoring, and I would reccomend keeping and eye on (Monitoring) the fill when the house next door is built.

Lets see what others say.

[Carl Brown]

When it is back filled the finish grade should not be within 4" of the cement type product it might just be stucco.

[Barry Adair]

The pony/knee wall is there to avoid exterior finish contact with soil as Carl said. This used to be an 8" industry-wide requirement now it's up to the AHJ.
I'd advise implementation of a drainage system and that the portion of wall below grade be sealed before soil is placed against it.

Brian's right-on about the step cracks unless deflection was present that doesn't show up in the photo, then an engineer would be an appropriate call.

Another case of stucco without weep screed, I see...

[Sean Corcoran]

Gentleman, what is the cause of the step crack?

[Marcel R. Cyr]

Originally Posted by scorcoran

Gentleman, what is the cause of the step crack?

Step Cracks in a Concrete Block Wall


Vertical movement in a concrete block or brick wall might appear as either vertical cracks but more often as step cracks in which the crack pattern follows the mortar joints between the masonry units in a stair stepping pattern.


Step cracks are very common in concrete block walls. It is not unusual for cracks to originate as horizontal cracks, and over time, begin to step down, or up, along the mortar joints.

Typically, there is a tremendous amount of pressure pushing from the outside, whether it be expansive soil, tree roots or other catalysts.
If there is no pressure coming from the exterior, sometimes the wall bearing the load of the house simply cannot handle the weight, and begins to fatigue.

Unlike horizontal or vertical cracks where the opposing sides of the crack are pulling away from each other, in a step crack your wall is pulling apart from itself in all four directions and needs to be stabilized accordingly.

At this point, there is very little structural integrity left in the wall, and it needs to be stabilized as soon as possible. If bowing of the wall has not already occurred, it will most likely begin soon thereafter.

Hope this helps

Marcel

[Ronald G. Chorey II]

Foundation engineer looked at it today. Needs a couple weeks to see if there is still movement. Also the soil around the footer is being undercut by water. There were also cracks in the garage slab, on the rear patio slab, there was separation of the rock wall away from the home and there was a small crack in the stucco at the parapet wall. He felt that it was good that I recommend an engineer, prior to the seller filling in dirt up against the wall.

He also stated that the soil that is put in needs to go in in steps, so that it can be compacted properly.

[Brian E. Kelly]

Originally Posted by rchorey

Foundation engineer looked at it today. Needs a couple weeks to see if there is still movement. Also the soil around the footer is being undercut by water. There were also cracks in the garage slab, on the rear patio slab, there was separation of the rock wall away from the home and there was a small crack in the stucco at the parapet wall. He felt that it was good that I recommend an engineer, prior to the seller filling in dirt up against the wall.

He also stated that the soil that is put in needs to go in in steps, so that it can be compacted properly.

Nice job Ronald.

[Sean Corcoran]

Thanks Marcel, couple more questions:

Does the step crack follow the mortar joints because the block is stronger than the mortar?

Also, could you just touch on how you would report a step crack? (verbiage)

Thanks,

Sean

[Marcel R. Cyr]

Originally Posted by scorcoran

Thanks Marcel, couple more questions:

Does the step crack follow the mortar joints because the block is stronger than the mortar?

Also, could you just touch on how you would report a step crack? (verbiage)

Thanks,

Sean

Hi. Sean;

There is no absolute way to properly report cracks in a block foundation or concrete wall.
It all depends on the observations at hand for the moment. Every one is different but similar in certain characteristics.

To be narrated properly, the information must be combined with specific on-site observations at the particular building in order to form a reliable opinion about the condition of that building's foundation. Anyone having concern regarding the structural stability, safety, or damage of a building, foundation or other components, should consult a qualified expert.

During a site inspection of cracked blocks, there are numerous variables to take into account and many unknowns.

Other than the fact that the crack relates to movement of some sort, the exact reason as to why it cracked is unknown to even the professionals to some extent.

In some cases, step cracking could be something as simple as the wrong type of mortar used when it was built. The stronger the mortar, the less adhering properties it has with the block work.
So basically, the safe way of reporting would be that there appears to be some movement in the block foundation based on the evidence of the step cracking.

I would recommend further evaluation by a foundation expert or engineer and move on.

Hope this helps.

Marcel

[Sean Corcoran]

Thank you Marcel. I have to say I very much value your contributions on this site. I've done a search of all your posts and they have added considerably to my knowledge base! Thank you for taking the time to answer my noobie questions!

[Carl Brown]

If they were to put moisture barrier and lath on all CMU the cracks would be covered.

Unless they were so severe they cracked the stucco.

Moisture penetration and freeze and thaw cycles can really cause a lot of problems.