Weep holes in glazing assemblies are only effective if placed properly - the last thing we want is to introduce more water than the system can handle… Execution can be tricky - there are no plain hard rules to follow - every system works slightly differently. Designs can be validated through testing - a helpful exercise can be to remove the glazing bead to monitor any residual water. Ultimately, water may come in, but how is it them managed to get out?
Another thing to consider is capillary action on large facades, changes in temperature can draw or suck water into the system. The way I interpret it is this, as hot air rises it pulls in cold air to replace it, this is what a draught is, cold air rushing in under a door, the same effect is happening on a window or facade, if it’s raining the water is coming in with the air through the weep holes or drainage slots on the pressure plates….
I was taught that any drain hole or slot should be no less than 6mm (1/4”) otherwise water will just bridge it and not drain.
It does get tricky, we should consider some of the factors below: 1. Placement: Weep holes must be strategically placed at the lowest points where water can collect typically in the frames of windows or curtain walls. This ensures that gravity can assist in draining the water out. 2. Size and Frequency: The size of the weep holes should be adequate to allow water to escape without being blocked by debris. Also, weep holes need to be spaced appropriately to prevent water accumulation in any one area. 3. Protection from Blockage: Weep holes should have covers or screens to prevent insects and debris from blocking them. This ensures continuous and effective drainage. 4. Slope and Pathway: The frames and sills should be designed with a slight slope towards the weep holes, facilitating water flow. Additionally, pathways inside the frame should direct water towards these exits efficiently. 5. Secondary Drainage Paths: In more complex systems, secondary drainage paths or channels may be integrated to handle any overflow or ensure that water is directed to the weep holes from various parts of the assembly.
2,5mm drain holes are to small
Understanding the intricacies of weep holes in glazing assemblies is crucial for effective water management in building envelopes. Proper placement ensures they function optimally without compromising the system’s integrity. Testing and validation are essential steps to gauge their effectiveness, such as monitoring water flow by removing the glazing bead. Managing water ingress and egress is key to maintaining the longevity and performance of architectural glazing systems. 👍
a wise mentor of mine years ago taught us all that water will always win and get into your walls/windows! the key is to admit defeat and provide water a way to the outside (weeps) before it gets inside!
La conception des drainages est fondamentale dans l'étanchéité à l'eau. circulation en chicane, dimensionnement de la colonne d'eau, section des évacuations, mise en œuvre des déflecteurs éventuels, protection des sorties de drainage, étanchéité des assemblages et passage des vis, protection des ruissellements pour éviter les surcharge d'eau.
I’ve lost count of how many times I’ve seen these sealed by people thinking that it will solve leaks. Only to find the leaks increase (for reasons obvious to us)
Another thing to have in mind is the pressure equalization holes that you must make in order to have the water flow freely from the drainage holes.
Head of Engineering Services, Southeast Asia
2moOf course always depending on some specifications but some systems provides safe solution to avoid uncontrolled water within the system…