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horizontal crack on clay block wall

horizontal crack on clay block wall

horizontal crack on clay block wall


I am interested in purchasing a house but there a quite a few cracks at various areas. The walls area constructed using clay blocks.
I've attached a photo of one of the worst cracks.
It starts from the corner of a door frame and runs horizontally where it meets another crack from the corner of another door frame at the other end.
Is this a serious concern?
What's the best method of repair?


RE: horizontal crack on clay block wall

Probably ---

Call in a structural/soils engineer or equal to give you some real idea!!

RE: horizontal crack on clay block wall

Looks like the wall being worked during a seismic event to me.

May have lost this section of the wall for lateral resistance.

You really need to have the structure inspected by a structural engineer before you sink your money into the money pit.

Mike McCann
MMC Engineering

RE: horizontal crack on clay block wall

First - Are you sure the units are "clay block" or are they "clay brick". - The crack pattern is consistent with might be seen since it starts at an opening corner , but the height to length ratios looks more like a brick wall.

The 2 crack shown seem to be in the surface coating and "die" within the wall without really being connected.

A professional on site with a good eye and small tool for taping may give you some information on the wall make-up and any possible on reinforcement.

Is the wall possibly just an infill walls with plaster? If so, it may be non structural for most designs and any frame distortion may have caused the cracks in the surface. I have seen hundreds of a 4"hollow clay tile interior walls that show some superficial cracks after an event, especially if it is an older structure.


Engineer and international traveler interested in construction techniques, problems and proper design.

RE: horizontal crack on clay block wall

the wall is constructed of hollow 4" x 6" clay blocks held together with mortar and plaster.
Yes the building was constructed 22 years ago.
The crack you are seeing in the picture is also the same on the other side of the wall i.e cracked straight through.

RE: horizontal crack on clay block wall

Is the wall an infill wall or is it in a frame structure, making it non-structural according most designs at that time?

I have seen 20 story loadbearing concrete masonry buildings in Brazil built using 6"(150 mm) thick partially grouted CMUs and also saw 4"(100 mm) thick partition walls in Spain used as partitions that just had a surface plaster. Both had no cracks evident, except for the cosmetic cracks that showed up very occasionally due to temperature ans shrinkage factors.

More information on the structure would be helpful, but for a home, I would think they would not be structural cracks, but just cosmetic and superficial based on the cracking patterns.

Clay masonry products have a very slight long term expansion (depending on exposure) and cement based products have a very slight long term expansion, so that differential could account for the tensile stresses to cause cracks in exposed surfaces.


Engineer and international traveler interested in construction techniques, problems and proper design.

RE: horizontal crack on clay block wall

If I were interested in purchasing the house based on this one photo, I would think again. As the OP said that "there are quite a few cracks at various areas", and as the house is unreinforced loadbearing brick masonry, I wouldn't want it. This could be as the result of footing movement, wind load racking, earthquake, or just shoddy construction. Whatever, avoid it.

RE: horizontal crack on clay block wall

The wall is an infill wall (hollow clay blocks held together with cement + red sand mortar, then plastered).
There may have reinforced concrete framing at the corners of the building. I didnt check, I took that for granted.

It's a load bearing wall, it supports the center of a gable roof (single storey home).

RE: horizontal crack on clay block wall

While the comments on this thread offer information, you really shouldn't make your go / no-go purchase decision based on these several comments which are based on one photo.

Per MiketheEngineer above - hire an engineer to evaluate the condition directly.

Things an engineer can investigate directly:
1. Close-up visual examination of the cracks - edges, age, etc.
2. Crack offsets
3. Relative floor elevations above the wall to determine foundation settlements.
4. Conditions of grading around the house perimeter.
5. Types of soils in the area and their behavior.
6. Structural load paths around and through the wall.
7. Specific costs of repairs in your city.
8. Available types of repairs (foundation underpinning, wall supports, wall reinforcing)
9. Having an engineer working for you for a fee who would be accountable to you.

There's probably others I've not listed but all of these aren't done well on this site based on one or more photos.

RE: horizontal crack on clay block wall

employ a structural eng and make sure hes insured

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