I'm going to replace these cracked bricks on the front of my home(see pic). What type of mortar should I use? Type S, N, or M? Is there a way to determine the type of mortar that was used when the home was built?

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  • What climate region are you in? Did you discover what caused the shift? Usually bricks don't split from water damage.
    – HerrBag
    Feb 28, 2013 at 23:12
  • @HerrBag, I'm in Maryland, between Baltimore and DC. I'm not sure what caused the split. The house was built in 1967. The crack is over a basement window. (Although, it doesn't extend all the way to the basement window.)... I recently bought the place. The gutter in this area used to overflow. I've fixed the gutter. I'm not sure if that had something to do with it. The foundation looks fine. Any ideas as to what caused the crack?
    – Laxmidi
    Mar 2, 2013 at 16:58

1 Answer 1


The mortar should be matched to the brick hardness (or stone hardness).

A soft, reclaimd brick might be matched to a Type N (750 PSI)

The type S, at 1800PSI would be my guess for these bricks.

The M, at 2500 PSI would probably be too hard.

A great tutorial from the Nation Park service:

Repointing Mortar Joints in Historic Masonry Buildings

  • Also this page has great information as a supplement. It describes the history of brick manufacturing, with dates. This can give you a good idea about what kind of mortar to use if you know how old the bricks are. Aug 17, 2016 at 23:14

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