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Old 01-02-2007, 06:13 PM   #1
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CMU foundation re-tro fit / 2nd story

Hi Everyone,

Blg. Dept. total PITA - won't answer ANY questions. Anyone have actual experience retro fitting C. Block foundation to support 2nd Story Addition?
My present foundation is 2 coarses hollow 6" CMU on a 7x12" NOT reinforced concrete footing. How can I make it support a 2nd story? I only need to do about 20 - 30' of it. (I would tear it out completely but those bstrds won't let me do it right). I have thought of carefully busting away most of the block except the back 1" then I could pour an 8" thick concrete wall against them. That doesn't fix the un-reinforced footer though. Maybe if the new wall was 10" thick I could sort of add an off-set footer next to the old with lots of re-bar?

Should I blow out sections every 6' and put in a big footer for a wood post OR maybe a concrete sono-tube post? This is just so retarded. If the BO would spend 1/2 as much time helping me as he does saying "I'm not going to design it for you" I would be out of his hair. But he won't..........

Ideas anyone? Thanks.


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Old 01-02-2007, 06:59 PM   #2
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The building dept. doesn't design projects, you must hire someone to do that, BUT if you showed up with a design that showed a 4" footing, 5 1/2" foundation on your application he should say THAT is not acceptable, YOU must have at least 12" wide footing and at least 8" wide foundation with rebar then i'll give you a permit OK I'll change it

good luck


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Old 01-02-2007, 07:17 PM   #3
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The problem is not with the 6" wall thickness. Some people are just a little backward and uneducated. I have seen 22 story buildings built out of 6" block with no steel or concrete columns - just loadbearing block.

Do not expect the building official to tell you how to do it since he is not qualified. He can only say what not to do and is not always right, especially on structural items.

Do you have a crawl space? You could run into a footing problem depending on your local code or soil. If the footing is OK, you could get away with filling the block or going to 8" block(not necessarily filled).

The existing wall can certainly take the load, but it may have to be grouted.

Since the building official may have already taken a position that it is not acceptable, you will need to convince him. Contact a structural engineer to see what options you have. The engineer may want to Take a couple of shallow soil borings to prove the strength of the soil.

Since your footing is not subjected to flexure (shear only, with is minimal) he may be able to use the existing footing as is.

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