Asked on Jun 14, 2019

How do I repair falling sheets of masonry on cellar walls?

WilliamSharonJudi1
+4

Answered

In this 1909 house with a Michigan basement, block walls were added in the 40's and the "knee walls" with dirt behind them were retained, but have a half to three-quarter masonry coating covering the dirt is failing. The big box store people are too young to have a clue as to what product or mix to use. I am thinking an old-school mason knows this situation, so seeking what KIND of bagged product or sand PLUS another, to mix and apply to falling sheets of old masonry. (The knee walls are 36" high, with a "24 inch deep "shelf" and then block wall to the rim joist.) Hope thie pix helps. Thanks a trillion!

q how do i determine the right masonry product for cellar walls
4 answers
  • Judi1
    on Jun 14, 2019

    I believe you are talking about a stem wall used to join the foundation to the vertical walls. The damage here looks like it might be a moisture issue. What is the underlying material? Is it concrete?

    • Joe Gemmill
      on Jun 16, 2019

      Yup. Stem wall or knee wall, with plain old sandy fill dirt under the thin mortar the you can see has been patched and re-patched over the years. Definitely hyrostatic pressure from NO gutter is the culprit. I was looking for what KIND of masonry mix (with a bonding agent) would work, AFTER the water issue is solved. Thanks for your input!

  • William
    on Jun 14, 2019

    Any mortar mix for concrete walls will work. No special mix. BUT you have a moisture problem that needs to be addressed first.

    • Judi1
      on Jun 16, 2019

      Most of the time stem walls are made with concrete and rebar, not just dirt. I think the video Sharon posted is very good. I think you would have to install the mesh to get the concrete mix to hold. My brother-in-law is a mason and when you are putting such a thin layer, you have to have something for it to adhere to as anything under 2 inches will crack. After it is dry you can apply 2 or 3 coats of drylock.

  • Sharon
    on Jun 15, 2019

    Here's an old school mason tackling old foundation problems (there are 9 parts) https://www.youtube.com/watch?v=nGH7eszfMvs

  • William
    on Jun 16, 2019

    Don't need the mesh. Once the moisture problem is solved use hydraulic cement to fill any voids. Then a skim coat of a latex modified cement mix. It has bonding agents in it. Can be applied from 1/8" to 1/2" thick layers. Then you can paint with Drylock waterproofing paint. Absorbs deep into concrete or block.

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