Throughout the interior side of my 1925 brick foundation are little metal vents embedded in the mortar at irregular intervals. Neither our home inspector nor our real estate agent knew exactly what they were for. The vents are about the size of a quarter.

They seem to simply allow moisture in through the wall, despite the waterproof paint on the bricks. I can't imagine this is the intended purpose.

Has anyone seen these before? Any idea what these are for?

Vents hammered into mortar of a brick foundation

Update, 30 August 2013: I finally got around to pulling some of these vents out. Behind them is... nothing. Just mortar. No tubing of any kind, just an approximately ping pong ball-sized divot in the mortar.

  • Do they go all the way through the wall? My uncle, 50 years ago, used to "joke" they allowed the wall to drain. I was younger then (grin) and believed him, every word. On his wall, the "drains" did not go all the way through to the inside wall. Jul 24, 2013 at 17:03
  • I'll have to get back to you on that next week... don't want to remove any until I close on the house!
    – Joe Shaw
    Jul 24, 2013 at 17:17
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    @JoeFromOzarks Your uncle's explanation is not inaccurate. To the OP -- Are you sure this is a "brick" foundation, and not a concrete block foundation? One of the problems with concrete blocks is that they have a tendency to wick moisture. Given the placement of what appears to be vents, I think this was a rudimentary attempt to correct moisture issues building up within the gaps, which can freeze and cause the mortar to pop out. My guess is that this was a crude attempt to fix a different moisture or drainage related problem.
    – Jacob S
    Jul 24, 2013 at 17:22
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    @Jacob S. (grin) Oh yes, you did say "not inaccurate." I've been coding all day and I've gone cross eyed. Still, my Uncle loved pulling my leg - to the point I had to research everything he said, his intention all along I suspect. Thank you for keeping me on my toes!! :) Jul 24, 2013 at 22:18
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    @BMitch Correct, these are on the interior, all around the foundation, and also in the brick chimney.
    – Joe Shaw
    Aug 1, 2013 at 16:28

2 Answers 2


They appear to be weep hole covers. Weep holes today usually consist of a vertical slot; the result of not putting mortar in a joint. This might have been a retro-fit to address a moisture problem since they are not evenly spaced and are round, which would make sense if holes were drilled in the brick for drainage.

Weep holes are vital to prevent rot of the structural wood framing that's probably on the other side and to minimize moisture inside the brick wall that can freeze and crack the brick in cold climates.

Couldn't find a definitive article with picture but here's more on drainage of brick walls.

  • In our case only the foundation is brick, the rest of the house is wood frame and shingles. So in this case I don't think the rot concern applies?
    – Joe Shaw
    Aug 1, 2013 at 16:32
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    Weep holes would be for exterior masonry. These are on the interior. If they were weep holes, you'd be draining excess moisture inside of your house. You also wouldn't have weep holes directly vertical from each other, they would be spaced evenly every several feet at the base of the wall.
    – BMitch
    Aug 1, 2013 at 18:08
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    Instead of speculating, next step would be to try to remove one. Then look in or feel in to determine if these are pipes and how far they go. From the picture, I get the sense that they are placed to address a specific issue, like a wet wall. It could even be that they shouldn't be there at all. That they are weep holes but put on the interior to avoid the labor of digging by a misguided homeowner or handyman? Aug 3, 2013 at 8:47
  • Just posted an update to the question, but having pulled a couple out there is just mortar behind them.
    – Joe Shaw
    Aug 30, 2013 at 19:31

They could be similar to these air vents: http://tamlyn.com/Alum%20Mini%20Circle%20Vent.html

Proper ventilation in enclosed spaces can reduce the chance for mold and mildew. If they are allowing moisture in, the proper thing to do would be to remove them and to fill the voids with concrete before sealing them over. I would also make sure there is adequate ventilation in the basement after you do this by installing a proper vent or other means.

You could ask for an estimate from a contractor and use that as a bargaining chip when negotiating for your home.

  • Something like these vents might have been put in after drilling in an attempt to "vent the wall" (I'm NOT saying it was smart or right) due to a mold problem which could be the discoloration underneath the paint. Aug 21, 2013 at 15:12

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