Brick deterioration

Old 03-04-20, 05:58 AM
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Brick deterioration

We have a cottage that is not heated during winter. It has a brick chimney/fireplace. (The house & brick are 70 years old.) Each winter quite a bit of brick material sloughs off from the surface and falls to the floor. Any idea what might be causing this, and what I can do about it?
Old 03-04-20, 09:07 AM
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Without seeing it my first guess is that it's simply poor quality brick. There isn't anything you can do to prevent it that I am aware of. The most common explanation I've heard is that the bricks weren't fired at high enough temperature. This is more common with old bricks and those that were on the outer edges of the kiln.
Old 03-04-20, 10:11 AM
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If it's on the exterior of the chimney (not interior hot brick), it could be parged and stuccoed with cement to seal it all together and keep it from chipping off.

If it's on the interior of the chimney, I'll have to defer to others. Sounds like it might need a liner, but that doesn't help with the structural integrity of the chimney.
Old 03-04-20, 05:36 PM
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Post a picture so we can see what your seeing.
Google "spalling".
Old 03-04-20, 05:48 PM
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Chimneys have caps that are usually made of mortar, sometimes with clay flues that have been mortared around.

If no maintenance is ever done, it's quite likely that the mortar cap is in a state of disrepair. Snow, rain, ice all take a toll, and if water is leaking down behind the brick, and it's repeatedly subjected to multiple freeze thaw cycles during the winter, it can cause the brick to blow up due to the high moisture content in the mortar between the bricks.

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