Industry Standards for Repointing of Masonry Walls
There is a procedure to be followed when it comes to restoring historical / heritage masonry so it lasts and retains its beauty. A large component of a brick or stone wall is the mortar that binds its units. For this reason, poorly executed mortar repairs immediately become a visual distraction, much like a bad note can wreck an otherwise beautiful musical harmony.
Furthermore, our collective heritage of masonry structures is in limited supply, as we're no longer building using traditional methods; and so incorrect repairs carried out on soft, porous masonry assemblies by masons inconversant in widely accepted preservation methodologies factually constitute an often irreversible damage to this very heritage. A deed which is punishable by law in Great Britain by the way -- an interesting fact that one may wish to keep in mind.
Below, you'll find essentially a PowerPoint presentation which illustrates elegantly enough how one is to proceed should he or she attempt to carry out a repointing project, whether it be historic or otherwise -- information which makes up a substantial portion of the knowledge base a conservator should possess in his or her repertoire; although following these guidelines should complement, but not supplant, the need for artistic judgment in our opinion:)
--Click on the first image on the left of the strip to open the full-size viewer.