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?
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.
Best Answer
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.