Homeowners have often contacted Weepa Products for advice on how to address damp and moisture problems in their homes caused by the entry of water through ‘weepholes’. To ascertain whether water could enter the building structure through the weephole, Weepa Products commissioned Griffith University in 2010 to conduct a study into the problem.

Results from the research revealed that that even under truly extraordinary conditions, water rarely enters weepholes; even if it does enter the weephole, it cannot be blown high enough up in the cavity to create internal damp problems. 

Weepa Products uses the diagram of a correctly constructed cavity wall (above) to explain this finding. The diagram shows the location of flashing, which extends from underneath the weephole upward to contact the internal skin of the cavity. This flashing guides and drains any moisture that might enter through a weephole, straight back out again.

It’s important to identify the real cause and source of damp and moisture problems in walls. Blocking the weephole cannot solve this problem and will, in fact, prevent the drainage of water and the airflow needed to completely dry the cavity, leading to catastrophic problems.

Possible causes of damp and moisture in homes

Flashing or waterproofing problems around windows and doors are usually the most common in homes. A waterproof membrane designed to channel water to the exterior of the home, flashing runs from the inside skin surface to the exterior skin surface in the cavity and is found around windows and doors as well as around the house just below the weephole on each level.

Being a critical component, flashing missed during construction in just one small area can cause hard-to-detect damp problems. Typically, the resultant damage is above or near the problem but this is not always the case with several instances being reported of poorly installed flashing on a top floor rear window causing flooding at the front of the house. This is caused by horizontal members directing water throughout a structure.

Other possible causes of damp or moisture include faulty roof installation or corrosion; faulty plumbing; and incorrectly installed brick ties or incorrectly drained air-conditioning units creating unintended conduits from the outer skin to the interior.

The first step to addressing the problem is to locate the highest point of dampness on the interior wall. Since storm water and accidental flooding will only move downwards through the wall, the source of this problem is almost certainly located above the visible dampness. Using an infrared camera will help detect the source of water by revealing the cooler areas of the wall and diagnostically solving water problems.