Definition
A weep, also known as a weep hole or weep‑brick, is a small opening intentionally left in a building component to allow water that has entered an assembly to drain out.
Overview
Weep holes are typically situated at the lowest point of an assembly—such as the base of a masonry veneer, cavity wall, retaining wall, window frame, or glazed curtain wall—to provide a path for moisture to escape. By facilitating drainage, they reduce the risk of water accumulation, hydrostatic pressure, and related damage such as freeze‑thaw deterioration, mold, or rot. Weep holes may also serve to vent air, helping to remove evaporated moisture from cavity spaces.
Etymology / Origin
The term derives from the verb “to weep,” meaning to let out liquid, applied metaphorically to building elements that “weep” water. The usage in architectural contexts dates back to early 20th‑century construction literature describing moisture‑management practices.
Characteristics
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Location and Purpose
- Placed at the bottom of walls, foundations, or other assemblies.
- Allow water that infiltrates from the exterior or condenses within to exit, thereby protecting structural integrity.
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Typical Applications
- Masonry veneer and cavity walls – positioned just above flashing; the cavity drains water back through the weep holes.
- Retaining walls – may incorporate plastic, clay, or metal pipes extending through the wall to a porous backfill, relieving hydrostatic load.
- Windows and curtain walls – installed above frames to prevent dry rot of wooden components and to vent interstitial condensation.
- Automotive water pumps – small weep holes protect bearings by releasing water that leaks past seals.
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Design Variants
- Open‑head joints – mortar is omitted at regular intervals (commonly every 24 in/61 cm), creating weep openings directly in the joint pattern.
- Cotton‑rope wicking – a short rope (≈12 in/30 cm) placed in joints wicks moisture to the exterior; less efficient and fire‑risk prone.
- Tubular weeps – hollow plastic or metal tubes installed at an angle to direct water out; may be concealed with grille inserts.
- Corrugated‑channel weeps – plastic corrugated tunnels form the bottom of mortar bed joints, providing numerous discreet drainage openings.
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Sizing Considerations
- Openings must be large enough to overcome surface tension and allow water flow, yet small enough to limit debris ingress and maintain aesthetic appearance.
Related Topics
- Drainage and moisture management in buildings
- Flashing (building construction)
- Cavity wall construction
- Hydrostatic pressure and retaining wall design
- Building envelope and weather‑tightness
- Condensation control in curtain walls
- Ventilation of interstitial spaces
All information is drawn from established architectural references, including the Wikipedia entry “Weep (architecture).”