Concern

[Juan C. Jimenez]

Is there any requirement that the CMU's be offset. The house was over 30 years and did not seem to be affected by this.

[Cameron Anderson]

Not really, even though the running bond was interrupted (that's called a stacked pattern when it's done right), it shouldn't make a big difference.

You could do one of two things, call it out for a mason to sign off on or say it's unprofessional and recommend regular monitoring.

[Kenton Shepard, CMI]

Especially not if the cells are filled. Probably only an issue if the chances of soil movement are high. I'd ask a mason or an engineer.

[Jeffrey R. Pope]

The placement of the lowest courses tells me there is little chance that these include reinforcing steel. In my area (CA), I would have no problem calling this out for further evaluation.

In addition, it is difficult (if not impossible) to completely fill the cells when the blocks are improperly placed.

With these pictures and the pictures in your other post, I would be painting this foundation installation "red" and deferring everything about it. "Unprofessional," "non-standard," "suspect," "contrary to normal building practices," whatever - I would not be endorsing this installation.

Concern? Absolutely.

[Michael Larson]

The ground does not shake here.

I have seen entire commercial buildings built with stacked CMUs.

[Jeffrey R. Pope]

Originally Posted by mlarson

The ground does not shake here.

I have seen entire commercial buildings built with stacked CMUs.

Understood, but their alignment as pictured allows for rebar and entry of concrete into the cells.

Look at the first two course in Juan's photo. The offset is in exactly a position that will obstruct the vertical opening of the first course.

Even in "non-shaking" states, I would imagine you would want concrete filled foundations as opposed to hollow blocks, no?

[Marcel R. Cyr]

Concrete Masonry Bond Patterns

Building code allowable design stresses, lateral
support, and minimum thickness requirements for
concrete masonry are based primarily on structural
testing and research on wall panels laid in running bond
construction. When a different bond pattern is used it is
advisable to consider its influence on the compressive
and flexural strength of a block wall. Some building
codes provide for variations in bond pattern to some
extent by requiring the use of horizontal reinforcement,
for example, when walls are laid in stack bond.

An irregular bond or anything less than running bond with dura-wall and vertical reinforcement would not be used in this area for longevity and code compliance.

Stack bond installations are used at times for exterior walls for aesthetics reasons and interior walls. Reinforcement is the key factor.



Your area may vary.

[Michael Larson]

Originally Posted by jpope

Understood, but their alignment as pictured allows for rebar and entry of concrete into the cells.

Look at the first two course in Juan's photo. The offset is in exactly a position that will obstruct the vertical opening of the first course.

Even in "non-shaking" states, I would imagine you would want concrete filled foundations as opposed to hollow blocks, no?

At beam bearing points yes but that's about it.

[Marcel R. Cyr]

Originally Posted by mlarson

At beam bearing points yes but that's about it.

Not quite. Depends on Residential or Commercial application.

Even Dry Stack block applications are installed in running bond.

Where on earth did you learn to install foundation blocks in a stack bond?

[Michael Larson]

Originally Posted by mcyr

Not quite. Depends on Residential or Commercial application.

Even Dry Stack block applications are installed in running bond.

Where on earth did you learn to install foundation blocks in a stack bond?

I didn't but I have watched them being built.

And who mentioned dry stack?

Maybe you could explain what is better about a running bond.

All stack bond construction is required to have a
minimum area of horizontal reinforcement equal to
0.00028 times the gross vertical cross-sectional area of
the wall. This requirement can be met using either bond
beams spaced not more than 48 in. (1219 mm) on center
or using joint reinforcement. Anchored masonry veneer
must have horizontal joint reinforcement, of at least one
wire size W1.7 (9 gauge) (MW11) or larger, spaced at a
maximum of 18 in. (457 mm) on center vertically. This is
equivalent to the minimum reinforcement stated above

http://www.ce.udel.edu/courses/CIEG407/TEK%2014-06.pdf

[Michael Larson]

School gym this morning.

[Marcel R. Cyr]

Yes Mike, pretty stack bond.
I know all about it.

I built schools for the better part of my life.

[Juan C. Jimenez]

Thanks guys. I'm still not sure if its a defect or not but given the other issues i recommended an evaluation.