Chimney Repointing: When Your Stack Needs It

Signs the pointing has failed

• Joints you can see into from the ground
• Sandy mortar or bits of brick on the roof or path
• Plants growing from the stack
• Damp on the chimney breast indoors

What repointing involves

The old mortar is raked out to a proper depth and the joints are refilled and finished so they shed water. Smearing new mortar over the surface does not last.

Check the top while you are there

The cement bed that holds the pots, called flaunching, cracks with age. Re-bedding the pots at the same time costs little once access is in place.

And the bottom

The lead flashing where the stack meets the roof is the other common leak point. If it has lifted or split, renew it during the same visit.

When repointing is not enough

Bricks that have lost their faces, or a stack that leans, may need rebuilding from the roof line up.