Chimney Repair - Masonry

Chimney DamageMost people don’t think about their chimney during the summer months, but summer is a critical time to get needed maintenance issues out of the way before cool fall weather arrives.

Masonry Repair
Masonry repair should ideally be completed in warm weather so that mortar sets up correctly.  Small repairs can be made using an accelerant mixed in the mortar during winter months, but larger repairs such as major pointing, removal and replacement of bad bricks, crown rebuilding or partial or complete tear down and rebuilding must be done in warmer weather.

Check the chimney now for signs of wear and tear or damage by storms. Look for spalling bricks, which are brick faces popping off due to water inside the bricks which freezes in the winter and expands. Soft style bricks absorb moisture more readily that hard style bricks and unfortunately, many chimneys are built with soft bricks due to their cost.  In the long run however, soft bricks will fail and part or all of the chimney will need to be rebuilt. While soft bricks may not become damaged on the rest of the house, the height of the chimney exposes it to more wind-driven rain which penetrates this area more easily.  Spalling bricks cannot be repaired and must be replaced with new bricks.

Deteriorated or missing mortar joints should be grinded out to good mortar, and re-pointed (also known as tuck-pointing) with new mortar.  Be sure to hire a qualified contractor to do this as mis-matched mortar color or joint style can detract from the look of the chimney. If most of the mortar is missing from the exterior of the joints as well as the interior in unlined flues tear down and rebuilding may be necessary.

Unlined flues should be lined with an appropriate liner for the appliance it is serving.  Most jurisdictions have required flue liners since the 1920’s, however, many homes had flue liners as far back as the 1870’s because the masons knew that liners keep the external temperature of the chimney down and prevent leakage of toxic gasses through the chimney chase.  If having masonry repair completed and the flue needs a liner, have this done at the same time to keep costs for scaffold down.

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