Failing Mortar in Old Basement

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  #1  
Old 03-11-18, 08:32 PM
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Failing Mortar in Old Basement

Hi there, looking for some advice on how to repair mortar. It's over a 100 year old home with concrete blocks above poured concrete. The blocks have no mortar at all left in some blocks.

Looking to repair with new mortar but I'm not sure on what type to use. I was doing reading that said no to use mortar that is stronger than the old brick or concrete block, that too strong mortar could destroy the block if used. The blocks are right around grade level.

It's about an inch space between the blocks and it goes 1 foot deep.

Is Type N Mortar suitable for this? Type S is stronger, but is it too strong for these old concrete blocks that are maybe from around 1900? Should I be making my own mortar with lime and sand?

And with whichever mortar I could just clean the old joints out, wet it before and just shove in the full foot length of mortar? Packing in tight as can be?

I'm over just outside of Chicago, if weather plays a part with the frost.

Thanks in advance!
 
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Old 03-12-18, 04:45 AM
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I don't think you have a mortar falling out problem. It looks like there never was any mortar holding those blocks in place. If it's above grade I would use N and below grade S.
 
  #3  
Old 03-12-18, 09:58 AM
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Should I have any worries about using too much Portland? Some say to use less Portland and more Lime, 1 -2 - 9 mix.
 
  #4  
Old 03-12-18, 10:08 AM
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To get the mortar in place use a grout bag, like a giant cake decorating bag. google grout bag. You want the mortar to squeeze through the bag. Richer mortar flows more easily than sandy. It's been a while since I used lime in a mix. Seems like lime is a good lubricant. When you get a mix that flows that is a good mix. Most people throw away the metal tip that usually comes with a grout bag. Once the joint is full tool it in well to compress it and finish it.
 
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Old 03-12-18, 10:30 AM
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I wouldn't over think the mortar too much. You're patching something that never had it. I would just use a mix that already has sand so you only need to add water.
 
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Old 03-12-18, 02:57 PM
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If you go the grout bag route you might need to lubricate the mortar, even presanded mixed mortar. Dawn dish detergent works well a few drops stirred into the mixing water before you add the dry ingredients works well. I think a detergent bottle cap full of detergent in five gallons or some similar ratio will work for you. Wet the bag with soap water before you fill it. A mkix that floews through the grout bag will be a good mix for the job. As Pilot Dane says, don't overcomplicate this..How much of this do you have to do?
 
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Old 03-12-18, 04:35 PM
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Not a lot. About double what you see in the pic. Thanks for the advice! Appreciate it!
 
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Old 03-13-18, 05:55 AM
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If you don't want to buy a grout bag you can just pack the mortar into the cracks. If doing it by hand wear gloves or it's pretty easy to do with two trowels or with almost anything at hand. You just need something to hold mortar like a trowel or board and something to scrape the mortar over to push it into the cracks. Even a big screw driver, Popsicle stick, paint stirrer or putty knife would work.
 
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Old 03-13-18, 12:36 PM
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Thanks again for the tips. I bought a tuck pointer last night and have some concrete trowels already. Gonna wait until the temps rises a bit, at least until it's above freezing at night I think.
 
  #10  
Old 03-13-18, 02:54 PM
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Those old blocks may be stronger than "modern" concrete block. due to the equipment available, the cement content of the mix was higher than modern block molding systems that use both pressure and vibration plus controlled curing. to produce what ever is desired.

Back100 years ago, the blocks were often made on site using crude portable (100# or so) molding machine that was moved to the site and molded the block out of aggregate delivered. - Sears and others sold thousand of those old "hand-tamp" machines in that era and earlier.

At one time, I had a home that had the old, heavy block (12" thick x 6" high x 24" long) and that is doing well after over 100 years (built in 1917).

Dick
 
  #11  
Old 03-14-18, 04:01 PM
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That definitely helps to know that they were made strong back then. Thanks for the knowledge!
 
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