35 y.o. 2 story colonial here in suburban Chicago. I’ve noticed that the brown sand on and off in the past 2 years that’s on the south unfinished store room. First time I didn’t think much of it, thought maybe it’s just some construction debris. Seems like the same spot where it came from, don’t ever detect ant/termite activity. Need answers/ help please. Thanks.
Brown sand coming out basement wall
Mar 02, 2022
Last reply: 4 years ago
3 Replies
Did it occur to you to look up & behind / under the insulation batts ? for the source ? Any renovation jobs in that area prior to this ? ie : drilling through the brickwork for security wiring or electrical or plumbing or what ever ? John T.
Looks like it could be insect related. Find the nest. Could be a full sized condo at this point.
I'm assuming that that is concrete wall, so I'm taking a guess here:
The mortar used for the parging layer is failing. Parging is a layer of mortar used to finish a concrete or block wall. The layer is basically reverting back to the ingredients from which it was made. Maybe it was mixed too dry back when it was applied or maybe there is enough moisture behind it that it never cured correctly.
From:
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"The first tricky part to parging is mixing the mortar correctly with the right amount of the right ingredients. The dry portions of the mortar are Portland cement, sand, and other aggregates. Adding just the right amount of sand is important because the parging mortar needs the sand to make it sticky. If you do not add enough sand, the mortar will simply slide down the surface and not stick; too much sand makes the mortar too grainy. Water is added to the dry mix, and we have parging mortar. Since this mortar dries very quickly, we only mix enough to use in 20 minutes."
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