So I have a field stone foundation and recently had gutter put on the house. There are a couple spots were water has been getting in. Once those areas are dry I'd like to try and fill them in. I was planning on using type S mortar. Is there something else I should consider using since these holes are where the foundation wall meets the floor?


1 Answer 1


Since this is a foundation type S is a good choice. I think type M may also work but you need the high strength mix, is the repair above grade or below?

  • Below grade, which is why I was thinking type S, but also I don't want to cause any issue at the base if I really should be going with type M.
    – user44111
    Oct 9, 2016 at 21:23
  • Both are acceptable for load bearing below grade. I have used S on victorians that I had to drill and repair for upgrades with great success slightly below grade less than 18". I think the local weather conditions may also play a role how cold is a low in the middle of winter it rarely gets below 20 deg F in this area.
    – Ed Beal
    Oct 9, 2016 at 21:34
  • We generally prefer the WEAKEST mortar that will do the job, (I.e.: recommend below grade, etc.). The reason, we want the mortar to crack when it settles, (and it will settle) and not the rock, stone, etc. so that the mortar joints can be repaired and not have to replace the rock, stone, etc.
    – Lee Sam
    Jun 24, 2017 at 1:22

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