Mortar failure is the breakdown of the mortar joints holding brick, block, or stone together, showing up as crumbling, powdering, or missing mortar that has lost its bond and can no longer keep water out or hold the units in place.
Mortar is meant to be the sacrificial part of a masonry wall: it's softer than the brick or stone around it so that any cracking or wear happens in the joint, which can be repaired, instead of in the brick itself, which is much harder to fix. Mortar failure means that sacrificial layer has run out of life, whether from age, the wrong mortar type for the job, or repeated water saturation, and the wall has lost the seal that keeps it weathertight.
Freeze-thaw cycles are hard on mortar specifically because water gets into hairline cracks in the joint, freezes, and expands, prying the mortar apart a little more with every cold snap all winter long. Using the wrong mortar type for the age and hardness of the brick speeds up failure even further, since mismatched mortar wears unevenly against the units around it. Once mortar starts failing, water gets behind it and starts working on the brick or stone too, so what starts as a repointing job gets more expensive the longer it sits.
More masonry vocabulary from the glossary.
The services where this term comes up.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
