Weep (architecture)
A weep hole, often shortened to "weep," is a small opening left in walls, foundations, or other building components to allow water to drain. Weeps are a crucial element in preventing water damage and maintaining the structural integrity of buildings.
Purpose:
The primary purpose of weeps is to relieve hydrostatic pressure and allow accumulated water to escape. This water can originate from rainwater penetration, condensation, or groundwater infiltration. Without weeps, this trapped moisture can lead to a variety of problems including:
- Material Degradation: Prolonged exposure to moisture can cause materials like brick, concrete, and wood to deteriorate.
- Freeze-Thaw Damage: In colder climates, water trapped within building materials can freeze and expand, causing cracks and spalling.
- Efflorescence: Dissolved salts in water can be deposited on the surface of masonry as the water evaporates, creating unsightly white deposits.
- Mold Growth: Moisture provides a breeding ground for mold and mildew, which can pose health risks and damage building materials.
- Structural Instability: In severe cases, trapped water can weaken foundations and walls, potentially compromising the structural integrity of the building.
Location and Design:
Weep holes are typically located at the base of walls, above windows and doors, and at other points where water is likely to accumulate. They are strategically placed to provide drainage pathways for water that has penetrated the exterior cladding or entered the wall cavity.
The size and spacing of weeps are important considerations. They need to be large enough to allow water to drain freely but small enough to prevent the entry of insects and debris. Common weep hole sizes range from 1/4 inch to 3/8 inch in diameter. The spacing between weeps is typically determined by building codes and manufacturer recommendations, and can vary depending on the type of wall construction and climate.
Types:
Weeps can be constructed in various ways, including:
- Open Head Joints: Leaving mortar out of vertical joints in brick or stone masonry.
- Plastic Weep Tubes: Small plastic tubes inserted into the mortar joints.
- Cotton Wicks: Absorbent wicks placed in mortar joints to draw moisture out.
- Voided Spaces: Creating small cavities behind cladding materials to facilitate drainage.