Mortar over bricks - Need repair tips


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Old 04-11-16, 09:07 PM
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Mortar over bricks - Need repair tips

100 year old building. I fixed the source of the problem (water) but now I need to fix the joint mortar between the bricks and then apply a skim coat. I think I can handle the brick mortar but don't have a clue where to start with the skim coat. Any tips?

Will this do the trick? Rapid Set 55 lb. Mortar Mix-04010055 - The Home Depot

 
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Old 04-11-16, 10:09 PM
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I could me wrong but it appears that the bricks never had mortar between them. Hence the skim coat. Rapid Set may work but it's easier to work with Sakcrete or Quikcrete mortar mix. Wait for Bridgeman or ConcreteMasonry to comment.
 
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Old 04-11-16, 11:24 PM
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I thought mortar was the same as stucco because the ones I think I have always seen at home depot say both on the bag (plus Type S). but I google imaged searched and quickrete and secrete apparently have different versions, some with fibers which might make it less prone to cracking. type S should be fine, a ~$3 60 lb bag would do that patch patch and probably have enough to do 6 more like that.

Blast it out with the hose to get sand out of bricks. Looks like the brick mortar joints were indeed done once upon a time but went bad and whoever skim coated it didn't re tuck the bricks. I imagine the whole wall looks like that under the skim coat. The mortar/stucco type s would be able to tuck those brick joints and do the skim coat. A tuck pointing trowel (only like 1/4" wide trowel) can be used or a grout bag (but you'll have to cut the tip and mix it very wet to get it out [ a grout gun would be better and wont' have to make it too watery which means less strength]), or use a stick and pack the mortar in. Make sure the bricks are still wet so the skim coat adheres well to them. You can also use a bonding agent if it's dry but for that wall, I'd just wet the bricks. Then just mix the mortar and trowel it on. If you don't have a trowel or want to but one just for this, you could probably use a block of wood or something.


It looks to me like the rest of the skim coat is a sponge float finish, aka wait for it to dry maybe 20 mins and use a wet sponge and make circles and the aggregate/ sand will come to the surface and look bumpy like the rest of the wall.

After about 5 hours (maybe more if it's hot and sunny on the wall), mist the patch with the hose. Do the same thing the next day and the next after that a couple times each day. This makes it cure slowly and makes it stronger.
 
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Old 04-12-16, 07:12 AM
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Yes, I agree with Type S. I use it myself.
 
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Old 04-12-16, 10:09 AM
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Most people tend to use a mortar that is too strong and sacrifice the assets of lower strength mortars. - Stronger is not always better unless you have a "Macho" complex.

The appendix of the ASTM requirements that you should use the lowest strength possible to carry the structural loads.

The old big traditional question is - "Does mortar keep masonry units apart or hold them together?"
 
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Old 04-12-16, 11:12 AM
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The old big traditional question is - "Does mortar keep masonry units apart or hold them together?"
That's a good question because I may have used a mortar that was too strong on a bluestone landing even though I used a bonding agent. The water must have entered some of the joints.
 
 

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