Tuckpointing & Repointing: what to know
Mortar is designed to be the sacrificial element in a masonry wall: softer than the brick or stone it beds, so that movement, salt and frost damage the joint rather than the unit. A joint is replaceable; a spalled brick face is not. Repointing at the right moment is the difference between a wall that lasts another fifty years and one that needs rebuilding.
What a proper job looks like
The deteriorated mortar is cut or raked back to sound material, typically around 20 to 25 millimetres deep, or roughly two and a half times the joint width. The joint is cleaned and dampened. New mortar is packed in tight in layers, then tooled to match the original profile once it has reached thumbprint hardness. Anyone proposing to smear new mortar over the face of old joints without cutting them out is not repointing; they are painting over the problem.
The mortar mix matters more than anything else
This is where most damage to Connecticut masonry gets done. Pre-1930s brick and brownstone were laid in soft lime mortar. If you repoint that wall with hard modern Portland-cement mortar, the joint becomes stronger than the units around it. Thermal movement and freezing water then have nowhere to go except through the brick, and the faces start popping off. The damage takes a few years to appear, by which time the contractor is long gone. Ask directly what mix is proposed for the age of your building and expect a substantive answer.
When to do it
Run a key along a joint. If it scratches out as sand, the joint is spent. If joints are recessed more than a few millimetres behind the brick face, the wall is collecting water rather than shedding it. Either is the signal to get a quote, waiting turns a repointing job into a rebuild.