Importance of Weep Holes


Weepholes are the gaps left between some bricks in external masonry walls. Australian Standards require them because they serve two important purposes:

1. Ventilation of the internal wall cavity - Without ventilation, mildew, dry rot and damp reduce the life of the internal wall studs and other building materials within the cavity. Inadequate ventilation is the main cause of "Leaky Building Syndrome".

2. Drainage - Water that enters the cavity due to capillary action, condensation, damage, or accidental flooding needs to escape somewhere. In tropical and sub-tropical areas of Australia it is not unusual to see water flowing from the weep holes on the prevailing side of well constructed houses after a 'gully raker' or monsoonal storm.


1. Pest Entry

Pest Protector

If weep holes are left unprotected they provide access to the wall cavity for rodents and insects. Swarming bees and European Wasps love creating nests in cavities. Field mice make a track through the weep holes looking for warmth. Snakes, cockroaches and spiders find refuge, and food, in the cavity. Down lights, extractor fans and holes for plumbing or electronics become the internal entry point for these unwelcome visitors.  

In desperation many occupants resort to blocking weepholes with any number of materials such as silicon sealants, rolled up paper, plastic, scourer pads, steel wool. Even some manufactured weep hole covers, guards and barriers have been designed with holes too small to allow adequate ventilation. These 'solutions' that obstruct air-flow to the cavity cause Leaky Building Syndrome which can be difficult and very costly to fix later.

Solution: If you're building you can have perfect vermin free weepholes from the start by using one of our construction products. If you've already built, our Protector Weep Hole Screen can be easily installed to keep these pests out whilst maintaining air-flow.

2. Termite Entry

Weepholes are a serious free entry point for termites. It's common to see garden mulch, timber and other refuse against walls, enabling termites to use them to use them as a bridging point into the cavity. Pest Managers are on the look out for this in their inspections but the damage can be done quickly and invisibly. 

Solution: Weepa’s Termite Protector Weephole Screen, made from bifenthrin infused plastic can be easily installed to deter termites for up to 2 years.  Bifenthrin is also known to deter ants and cockroaches and early anecdotal studies are very promising.  If you also need bushfire protection this product can by used in conjunction with our stainless steel Protector Weephole Screen.

3. Entry Point for Sparks and Embers during Bushfires.

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Weep holes provide access for embers during bushfires sometimes with devastating consequences. Sparks enter the wall and roof cavity and the house ignites ‘from the inside’. It’s common to hear stories about firefighters saving houses in the direct path of a bushfires only to find houses further back suddenly exploding into flames. 

In Australia the Building Code for bushfire-prone areas (AS3959:2018) has specific requirements for ember screening in weep holes in all houses built in areas of declared bushfire risk including BAL-A12.5, BAL-A19, BAL-A29, BAL-A40, BAL-FZ.

Solution: Our range of Bushfire Compliant Products for use during or after building help you to meet Australian Standards and prevent the entry of embers and keep the cavity safe.

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The Weepa range is subject to Intellectual Property Rights. Aust Pat Nos 713335, 762230, 2007237177, 2007215369, 2008271915, 2013211506. Aust Pat Aps 2018902177, 2019900971. International PCT AU2007/000004, PCT AU2014/000123, PCT AU2019/050629. NZ Pat No 567674. NZ Pat Ap 716834. Sth African Pat No 2008/03841. US Pat Nos 8171677, 14/908620. Canadian Pat Nos 2629033,2916320.UK Pat No1984580.Des Reg137021,150609,156915.Aust TM 775282,NZ TM 961710,US TM 1145302.