Type N or Type S Mortar on a chimney?

Old 04-12-12, 07:29 PM
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Type N or Type S Mortar on a chimney?

I had a chimney built about 2 years ago. The chimney is 4 feet wide and about 33 feet tall. They guy who built the chimney used type N mortar. The corners of the lower part of the chimney are falling out. The mortar the joints seem to be cracking sporadically all over the chimney. I've been told that he used the wrong mortar and should have used type S? Needless to say this needs to be repaired. Whats the best way? Thanks so much!
Old 04-15-12, 07:20 PM
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For a chimney that tall (lots of weight!), I suspect a stronger mortar should have been used, although there may be other issues as well. Either Type M or Type S. Although I'm only an amateur brick and/or block layer, I've never used Type N, as it occasionally had performance problems just like you're experiencing (as I recall, it has a compressive strength of less than one-half of Type S, and only (less than) one-third of Type M.

I suspect it's time to bring the chimney's builder back into the picture, and ask him how he plans to repair his mess. Should he refuse to do anything, your option is to have the thing completely removed and replaced by a different brick man, and send the bill to the original guy. And take him to Small Claims court if he chooses not to pay.

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