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The Humble Weep Hole

September 14, 2017 0 Comments

What are Weep Holes?

Brick Homes are Using Weep HolesWeep holes are a prescribed solution for protecting a home against the threat of damp and associated problems. They are a small hole in the external wall of a building that makes it possible to drain water from masonry construction. The holes can be found between the bricks in the external masonry.

The purpose of Weep Holes is twofold:

Drainage of condensation or other water that has built-up between the walls

Water can enter masonry through small cracks in the masonry or cement-work, condensation or through flooding of an area due to unusually heavy rains. Weep holes allow the water to run out and away from the house, ensuring the water does not sit and create mould or other problems for the dwelling.

Ventilation of the Wall

Buildings that have a lot of water in the building cavities can suffer a number of problems. Mould, mildew or dry rot are common in poorly ventilated buildings, as well as associated household pests that may enjoy living in that environment.

Weep Holes improve the quality and life of housing and other buildings, and remove unnecessary costs involved with maintenance. With cavity ventilation ‘built in’, this removes one concern about the deterioration of buildings in the hot and somewhat damp Australian climate. Wood and other materials can break down in damp climates, and weep holes increase the chance that they will be dried out with effective ventilation. In addition, by removing the chances of mould, this also removes a health risk to the inhabitants of the buildings (who as a builder, in most cases will be your clients).

Looking critically at Weep Holes, one could say they do not offer enough ventilation, and this is both by design and due to quality. The design of the holes are small and may not be large enough to allow significant ventilation flow that will effectively dry the internal masonry. When building the structure, cement can slip back behind the wall as bricks are compacted and can block weep holes lower down the walls, again removing the benefits of the weep holes. With new building materials and better forms of ventilation on the market, some say Weep Holes do more harm than good as snakes and spiders and other pests gain an open door to the building, and rain from excessive storms can also enter the building through the very holes developed to keep moisture out!

However, despite the fact that some homeowners and builders agree not to place Weep Holes due to aesthetics, failure to place a Weep Hole can mean that the porous rock materials used in buildings, such as brick, will continue to absorb moisture and create a damp environment. This will result in the many problems listed above.

The building standards body agrees that Weep Holes are the best solution for these challenges. Australian Standards 3700 – 2011 Section 4.7.2 states that “Weep holes shall be provided wherever it is necessary to drain moisture from or through masonry construction. Where flashings are incorporated in the masonry, weep holes shall be provided in the masonry course immediately above the flashing, at centers not exceeding 1200mm.”

Filed in: Trade Tips

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