PDA

View Full Version : concrete block separation. problem or not?



Mark Nixon
09-20-2011, 06:16 AM
These pics don't really show the condition as well as I'd like but they may help. There is a separation between the two rows of block in the center of the photos. The separation is along the entire wall. It is also in the center of the wall which I believe is typically where shrinkage cracks appear first. The other rows of block above and below do not exhibit this separation. I probably would not have flagged this as a problem except for the "apparent" seepage that is occurring in the corner (first pic). Also, I did not observe any inward bowing along the separation line. Any opinions as to whether this is separation from "hydraulic" forces or just typical? btw house is circa 1980.

Thanks

wayne soper
09-20-2011, 04:43 PM
Did you put a staight edge on the wall?
If no bowing it looks OK but still is being pushed from outside water pressure.
What was the drainage at the exterior walls in that location?
Roof and ground.
Got any pics of the outside of that area?

If no lateral movement it should be monitored and drainage adjusted to remove pressure.
You're report should read to the effect that movement could increse in the future if adjustments arent made, and repairs to the foundation wall could be required if left unattended.
You want them to repair the cause, whatever it turns out to be, and if it takes getting and engineer out their to tell them their downspout drains, or exterior grade is pushing water against the house, then that's what they should do.
If you are confident in prescribing the proper repair, do so.

James Duffin
09-20-2011, 04:48 PM
The horizaontal crack looks like a problem with the wall pushing in. I would pass that off to a foundation person.

Mark Nixon
09-20-2011, 06:47 PM
Thanks for the replies. Here's a pic of the outside of the area (rear corner behind the deck). I think I will take your advice and suggest a foundation engineer clear it as ok if it is. I did not note any drainage problems. The house sits at the high point of the lot with downward sloping in the front and rear.

Eric Barker
09-21-2011, 07:15 AM
Mark, I agree with James, lateral cracks are not a good sign. It is apparent that the pressure on the wall was enough to break the mortar bond on the CMU. As a result the wall now has less ability to resist the pressure and I would expect that inward movement would now be accelerated.

Even if the surface grading slopes away from the foundation you can still have grief with expansive soil. It can also be possible for a clay layer underneath the diverts water back towards the wall. Obviously outside of what you know from a visual observation which is why a soil engineer should be consulted.