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sand deposits by chimney column

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Here is a fun problem.

Where did these sand deposits come from both on the front and the side of a massive chimney column of a 70's brick ranch?  The column rises from the ground up through it all, has a rectangular and a square clay flue, one for a gas furnace vent, another for a fireplace that was fitted later with gaslogs.  Column up top lacks a cricket, as modern codes would require, but I could see no roof leaking around the column perimeter despite the really sloppy flashing.

House has been unoccupied for an unknown time, no disclosure available.

My thinking is that the sheer mass of this column's faces has resulted, in a wetter than average year, in moisture migration towards the ground, that pushed this sand out of the mortar joints.




Edited by Jim Baird
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I've found several chimneys where the mason filled large voids between the terra cotta flue tiles and the surrounding block or brick with sand.  It's usually spilling out somewhere.  These are in PA and NJ all built from about the mid 60s to early 70s.

No idea if that's what is happening there, Jim.




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My thinking is that this column absorbed a lot of water in the course of a very wet year, (69 inches in an area that averages 45, 12 of which inches fell in December), and the migration down and out pushed this sand from those joints.  Nobody living here was around to vacuum it up.

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I've never seen it either.  Mechanism might be water trying to get back to the ocean, as it all does, mortar being saturated from above by force of gravity, but not in amounts enough to carry lime along enough to make a proper drip and stain onto surface, like I have seen from uncapped parapets.  Inside it is dry.  This sand so obviously fell from these joints there needs to be a physical reason why.

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