There's no fixed calendar for repointing a chimney. It needs to happen whenever the mortar joints have eroded enough to let water in, which for most chimneys in the Blue Ridge foothills works out to roughly every couple of decades, though older lime mortar, harder weather exposure, or a lot of sun and freeze-thaw cycling can shorten that considerably.
Mortar is built to wear before the brick does. It's the sacrificial part of the wall, softer than the brick around it, so it erodes first and protects the brick from having to absorb repeated freeze-thaw cycles on its own. Repointing means grinding out the failed mortar to a consistent depth and packing new mortar back into the joints, which resets that protection instead of waiting for the brick itself to start taking the damage.
A chimney at higher elevation, on the shaded north side of a roof, or built with an older lime-heavy mortar mix wears differently than one on a sheltered south wall repointed at some point with modern mortar. The freeze-thaw cycles that run through the Blue Ridge foothills all winter accelerate mortar erosion, so a chimney up here can need attention well before that general range if the joints were never especially tight to begin with.
Age alone isn't the test we use. We look at joint depth, whether mortar is crumbling to the touch, and whether water is tracking behind the brick, and repoint based on what the mortar is actually doing rather than a set number of years on the calendar. Catching it while the mortar is failing but the brick is still sound keeps the job to repointing instead of turning into a rebuild.
More on this from Chelo's Brick & Stone.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
