# CMU Vs' CIP



## MSLiechty (Sep 13, 2010)

I have a 110' wall that backs to a storm drain channel, where the water district raised the channel and soil level. This wall has been in place since 62' and as you can imagine is in pretty bad shape, H columns on 8' centers 6" block Non filled Very little steel etc...

I've considered replacing it with poured in place concrete if i can get city and water district approval. since its currently 6' tall anyone on the service road can look directly into my kitchen/ dining room. I seriously doubt they are going to kick down any $ for the replacement. But I'd like to go at least 7' tall. 

Most of us that back the channel and surrounding streets have added a course or 3 to the existing 6' tall wall to cut down on noise. 





These pictures are 7 years old its a a fair amount worse than this now.
Most columns have a vertical crack from top to bottom


Anyone have any thoughts on which will be more expensive?


ML


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## JBM (Mar 31, 2011)

Post a pic and we will tell you how to fix it up.


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## Tscarborough (Feb 25, 2006)

That is terminal. It is caused by the reinforcing wire rusting.


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## JBM (Mar 31, 2011)

Its pretty good blockwork though.


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## Tscarborough (Feb 25, 2006)

They probably used black wire, it was pretty common for this type work.


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## concretemasonry (Dec 1, 2006)

That looks like a shear crack and is not caused or affected by joint reinforcement.

What kind of load or soil is there on the other side of the wall? If there is a load, the vertical rebar (if used originally) would transfer the loads and prevent cracking. Normally, in CA the privacy walls are 6' to 8' high and the municipalities have "canned plans available for block walls.

The existing wall may not be strong enough to carry the additional load from the regrading and modifications.


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## Tscarborough (Feb 25, 2006)

I am going to differ with you on this one, Dick. The only time I have seen the mortar pushed out like that have been un-galvanized horizontal reinforcement swelling.

Edit-If it was shear there would also be displacement of the units.


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## MSLiechty (Sep 13, 2010)

When they regraded the road bed they raised the soil level. It's about 3' up the wall


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## thom (Nov 3, 2006)

Check your engineering codes. I believe ours are standard.

An unreinforced wall (as shown) can have at most 16" of elevation difference between the two sides. Any more than 16" (two blocks) and it becomes a retaining wall with the associated regulations.

An unreinforced wall (as shown) can max out at 6' tall (measured from the side that shows the most elevation above ground). Anything taller than 6' requires engineering and reinforcement. If the pickets on the top extend the wall above 6' it is a code violation.


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## fjn (Aug 17, 2011)

IMHO,both concretemasonry and Tscarborough have submitted very valid ideas as to the cause of the problem. The fact that the grade has been raised reminds me of an article i read pertaining to block walls below grade on one side. In that article,it was mentioned that a small seperation of soil (approx..25 in.) forms at top of grade in dry weather,wind blown soil particles enter the crack over the years,when rainy season hits,that "extra" soil is enough to stress the wall and cause horizontal cracks similar to photos !


Having said this,Tscarborough raised a valid point,my take, the problem is probably a combination of both concepts.


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## MSLiechty (Sep 13, 2010)

thom said:


> Check your engineering codes. I believe ours are standard.
> 
> An unreinforced wall (as shown) can have at most 16" of elevation difference between the two sides. Any more than 16" (two blocks) and it becomes a retaining wall with the associated regulations.
> 
> An unreinforced wall (as shown) can max out at 6' tall (measured from the side that shows the most elevation above ground). Anything taller than 6' requires engineering and reinforcement. If the pickets on the top extend the wall above 6' it is a code violation.



Correct its a code violation, but B & S seems to not bother anyone about it since nearly everyone does it. Its looks really pathetic driving down teh street and seeing abouty 15 differnet wall extensions. 

I realize it will be a retaining wall that's why I want to do it once and raise the height at the same time. In the first picture you can see the new CMU wall on the opposite side.... Typically its just cedar fences between neighbors I talked them into splitting the cost of CMU so it doesn't need to be done again in out life time. I had the mason step up 1 coarse higher half way back It was inspected and BI has no issues with it.

for a max height 6' wall the city requires 26" x 12" footer with 3-#4 in the and 1-#4 steel on 24" OC vertically and 1- #4 32" OC horizontally. An 8 foot wall required engineering.

I was thinking CIP may be less expensive

ML


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## NJ Brickie (Jan 31, 2009)

I'm guessing you really only want to know what will be cheaper to build. I can't say for CA but in this area a CMU wall will be less expensive. We do not do CIP walls but are always cheaper then a CIP wall. 

Also if you wanted to spend a little more. Since this wall is so prominent in your yard. You could use a decorative faced block such as a split faced or ground face block. I know there are patterned forms for CIP walls. But I have yet to see a CIP wall with a decorative pattern finish that l would want on my property.


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## MSLiechty (Sep 13, 2010)

Brickie I agree. I just don't want to deal with it ever again, was think CIP may last longer/ be less expensive When we had the other wall done I was quoted $110/LF for 6' tall minus the demo and haul off! There is no easy way of getting 990 block's back there except by hand through a 40" wide gate 

ML


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## NJ Brickie (Jan 31, 2009)

There are probably a few companies that could give you a quote for both. 

What is on the other side of the wall? The way I understood it was there was a road. If that is the case, could the block truck come down that road? The boom on the truck would be able to spot the block right down into your yard.


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## MSLiechty (Sep 13, 2010)

NJ Brickie said:


> There are probably a few companies that could give you a quote for both.
> 
> What is on the other side of the wall? The way I understood it was there was a road. If that is the case, could the block truck come down that road? The boom on the truck would be able to spot the block right down into your yard.


its a dirt service road for the water district behind a locked gate... I will not be able to get access to it.

ML


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## JBM (Mar 31, 2011)

If the wall is structurally sound and is just spotting some mortar popping then just stucco it. You can apply this http://www.silpro.com/datasheets/Stucco8_5x11.pdf direct to the masonry. Power wash the day before and apply like a plaster. It is said to be waterproof so getting it below grade would be advisable.


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