How to repair cinder block joints with missing mortar?


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Old 09-09-17, 02:12 PM
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How to repair cinder block joints with missing mortar?

Hi;
I have a 1908 house with a basement that was probably added in the mid 1970's. Part of the basement is a load bearing cinderblock wall. The cinderblocks are in great condition, the wall is straight and there is no bowing, cracking or shifting. However, the mortar in the joints is completely disintegrating. It pretty much crumbles to sand with light scrapping (no hammering needed).

The problem is all the mortar comes out with light cleaning or scrapping and I am left with a void. (I have just done a few vertical joints so far). Is it possible to fill the joints again and maintain structural integrity?

I do not have access to the other side of the wall (2/3 of the wall is under a very tight crawl space and 1/3 of the wall is part of the outside foundation). The wall is about 6 ft tall and is on a cement foundation that is also very solid - no cracks or shifting either.

It seems like I would need some type of backing to effectively re-mortar the joint. Is there a way to do this? Or does this wall need to be completely rebuilt (by a professional of course, I'am not messing with a major load bearing wall). Thanks.
 
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Old 09-09-17, 02:21 PM
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Welcome to the forums!

Unless you have some settling issues I'd be incline to just point up what mortar joints I could. If nothing else that should slow down any further deterioration.
 
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Old 09-09-17, 04:58 PM
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Thanks for your help. Luckily there is no settling.

Any thoughts on how to fill the joints in which all the mortar is gone? I could see pushing in a large amount of mortar into those voids without being able to form a firm mortar joint. Could I use a bit of expanding foam at the back of the joint, not to replace the mortar, but to make a firm backing to help pack the mortar into the joint firmly?

David
 
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Old 09-10-17, 02:30 AM
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While I've laid/repaired block for myself, family and friends I'm not a mason. I wouldn't think it would be that difficult to force the enough mortar into the open joints. You'd want the mortar mixed a little on the stiff side. I'd be leery of spray foam, mainly because it's easy to make an unsightly mess.
 
 

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