Weep hole

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Weep hole
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Weep hole and ventilation openings are elements of the brick construction designed to help with drainage and airflow in the brick chamber. Masons Vents bring The advantages of a clean recess with a clean and tidy professional finish.

Ventilation is the process of exchanging air in any space with the intention of improving air quality. For a brick cavity, this means replacing humid air inside the cavity with drier air from outside. 'The Brick Vent' can be used in conjunction with any cladding system that requires a ventilated chamber, including bricks, blocks, stone or plaster finished with masonry veneer[1].

Types of weep holes

Main types of weep holes are as followed[2]:

  • Open head joints

Uneven joints of the head, located at regular intervals at the base of the cavity, are very effective and are the easiest type of weep hole to construct. Since these flushing holes create holes that extend the entire height of the head joint, the cavity would need to be filled with mortar upside down in the base course to render them completely ineffective. In addition, full-siz holes do this by easily checking that the weep holes are open to the cavity.

  • Louvered vents

Aluminium or plastic blind openings are sometimes used in conjunction with open head joints to keep insects out of the cavity. Ventilation holes with openings are installed in the head joints, just like a wall constructed. Ventilation openings are available in different colors and are recommended at the top and bottom of the walls with glazed hollow bricks.

  • Rope wicks

Cotton cord is also commonly used for weep. Cotton fibres have the effect of wicking moisture away from the cavity to the outside of the building. However, the ability to weep can be significantly weakened by mortar droppings accumulating on moisture at the entire height of the head joint. Holes, which are available in different sizes and colours, are placed in the head joints during the construction of the wall.


Weed holes are required in the brickwork head joints directly above all built-in flashings. Weep holes can be open head joints, holes formed by oiled nylon rods, plastic or metal pipes, fibrous or winged ropes. Open joints are fitted with ventilation holes or screens to protect against insects and rodents. Weep holes should have a minimum freeeter of 1/4 inch, pipes used for weep holes should have a minimum inside freeeter of 1/4 inch. Weep holes are preferred, as open jont heads covering more than 32 inches in the middle, although within brick walls it is generally recommended that they be placed no more than 24 inches per centimetre. If a rope or rope is used, the material should be at least 16 inches long. Weep holes other than open joints should be no more than 16 inches in the middle.

Wall system drainage is critical to proper operation. Reconstructing two to six inches of grave or damage material directly above the flash will help to ensure proper damage to the wall and effective drainage of water into the weep holes. Drinking material or pea gravel will act as a flushing field in the wall system and help prevent mortar droppings from clogging holes[3].

Elements of drainage cavity

Five essential elements of drainage cavity[4]:

  1. The external moisture content (vertical section of the wall equal to the width of the masonry element) of the masonry provides the first resistance to moisture penetration
  2. At least one inch of air space
  3. Interior extruded from masonry or other material such as frame wall
  4. Flashing at all gaps in the drainage cavity looks like at the base of the foundation and around the openings for such windows.
  5. Weep holes at all machining points - recommended 33 inch spacing.


  1. mpb.co.nz 2019, s. 1
  2. L. Walter, 1992, s.1
  3. J. Rumbarger 2003, s. 195
  4. bpgwi.com 2019, s. 1


Author: Anna Syjud