Repairing cinder block walls.

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Old 04-04-19, 06:39 PM
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Question Repairing cinder block walls.

I have a couple of cinder block walls around my yard. I've noticed that along the bottom of the walls, there appears to be very little mortar between the blocks on the first row nearest to ground level.

Is this normal or has the mortar eroded away? My neighbor said the gaps are probably to allow water flow. If it erosion, how do I go about repairing the walls?
 
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Old 04-04-19, 06:43 PM
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How to Replace Top Row of Cinder Block Wall

I recently took off the top row of one of my cinder block rows because they were in poor condition. I was actually able to remove them just by wobbling them loose because they were no longer attached to the rest of the way. It looks like they may have been added after the original wall because they're decorative while the rest of the wall is not.

Anyway, I'd like to add back a new row of regular blocks to the top of the wall. How do I do this? How should I tie in the new row to the existing wall?
 
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Old 04-04-19, 06:55 PM
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I combined your two cinder block wall threads into one thread as the topic is the same.
 
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Old 04-05-19, 12:49 AM
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WIthout a picture it's just a guess, don't know if these are retaining walls or what.

It's feasible they are not mortared in place to allow for drainage.

Typ block walls are assembled with mortar!
 
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Old 04-05-19, 02:37 AM
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Pics would be helpful, here's instructions for posting pics - https://www.doityourself.com/forum/e...-pictures.html

Are these retaining walls? how tall? any idea as to how old?
 
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Old 04-07-19, 05:23 PM
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Here is a poor picture of the wall. It's just a plain block wall dividing my yard from the neighbor. I've already removed the decorative row of blocks on top that were barely hanging on. I'd like to learn how to replace the top row with a new row of regular blocks.

Also, this is the wall where the many of the ground-level row of bricks are missing most of the mortar between blocks. Just wondering if this by design or if it's just eroded away and needs to be repointed.
 
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Old 04-08-19, 02:22 AM
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You'd scrape off any paint on the top edge and then mortar the new block in place.
Could you post a pic of the missing mortar at the bottom?
 
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Old 04-08-19, 01:15 PM
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I've attached some additional pics. Some follow-up questions:

1. There's no paint on top - just old mortar. Do I need to chip all of that old stuff off before applying new mortar?
2. Do I need to do anything like drill in some steel anchors or something to properly tie in the new top row to the existing row?
3. How do I fix the zig-zag crack that runs in the wall?
4. In the 2nd pic, you can see the gaps along the first row - is that by design or should I refill those in?

Finally, the existing block dimensions are 15.5" length x 7.5" tall x 5.5" width. Where do I find matching sizes? The closest I can find online is 6x8x16 - maybe that close enough?

Thanks!
 
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Old 04-08-19, 03:29 PM
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1. There isn't much old mortar on top so definetely remove it. If you leave it in place you won't be able to get a consistent mortar thickness between your new blocks and the old.

2. Nope, just mortar the new block in place. Mortar is all that holds many walls together.

3. There isn't much you can do to fix the zig zag crack. Thats probably the result of an improper footer so part of the wall is settling and moving.

4. Those gaps appear intentional. I would leave those gaps unfilled.
 
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Old 04-08-19, 03:44 PM
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Thanks so much for your help. How about the sizes?

Finally, the existing block dimensions are 15.5" length x 7.5" tall x 5.5" width. Where do I find matching sizes? The closest I can find online is 6x8x16 - maybe that close enough?
Also, would it do any harm to try and backfill in the cracks with fresh mortar?
 
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Old 04-09-19, 02:59 AM
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8"x16" is a standard block size although it is actually smaller allowing for the mortar. The 8x16 block you found will be the same size. It won't hurt anything to tuck point the cracks although it may be more effective if you chisel out some of the mortar first.
 
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Old 04-13-19, 09:02 PM
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That all makes sense. I purchased a block and it matches up perfectly. I want to add a top cap to the replaced top row of blocks. How long do I need to wait after laying the replacement block row before I can start putting on the top cap?
 
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Old 04-14-19, 02:10 AM
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You can usually lay several courses of block at a time so you should be able to install the cap at any time.
 
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