Masonry Flashing & Weeps
CSI Division 04, Masonry
Metal or membrane flashing embedded within a masonry wall, at the base, above openings, and at shelf angles, that catches water getting past the outer wythe and directs it back out through small weep holes spaced along the wall's base, the drainage system that lets a masonry wall manage water intrusion rather than trying to stop it entirely.
Why it matters
Masonry isn't actually waterproof, water is expected to get behind the outer wythe, so the flashing and weeps are what actually keep that water from accumulating and soaking into the wall assembly, not the brick itself.
On a real project
A mason installs through-wall flashing at the base of a CMU backup wall, lapped continuously and turned up behind the brick veneer, with weep holes spaced every 24 inches along the flashing to let collected water drain back out.
Who this matters most to
A Mason installs the flashing and coordinates weep hole spacing during construction. A QA/QC Inspector verifies flashing laps and weep spacing before the wall is closed in.
Where this goes wrong
A mason skips weep holes at a shelf angle flashing to keep the coursing looking clean. Water collects on the flashing with nowhere to drain, and it eventually backs up and soaks into the wall assembly, showing up as efflorescence and staining on the interior finish months later.