historic bricks and type N mortar

[darthsoilsguy2]

Came across a project in new england, where the mason completely rebuilt some 7ft tall triple-wythe brick masonry piers with 150+ yr old bricks using type N mortar. it is common knowledge that this is a no-no if it were a repointing job with lime mortar behind... but, most of the references out there don't discuss full reconstruction with old cleaned brick. all the references discuss matching mortar and brick hardness, but i see this as a brick spalling concern for point loading at the cementious repoints, and i have a hard time imagining the failure mechanism if the bricks are fully bedded. Also, it doesn't appear that there is a lot of info about strength testing on bricks to get a sense of the quality compared to today's stronger bricks. there isn't much out there about full rebuild in the Historic Preservation references so i figured i'd throw it out to the web and see what your thoughts are.

 

[dik]

FYI... see pages 4 and 5... many historic brickwork walls have been seriously damaged by improper renovation/restoration.

Dik

 

[darthsoilsguy2]

this articles seems like it is more focused around replacing a few bricks and repointing the face. i strongly agree with that... but.... The condition is the complete replacement of a structural element using repurposed old bricks with N mortar.

 

[dik]

Same thing applies... doing a wall or doing a few bricks... it's the methodology of approaching the problem and what to look out for.

Dik