Facade look beautiful. It’s all shiny glass and looks fine that way. Apart from looking good facades also provide for protection to the inhabitants of the building. Faulty facades can cause leakages coming in the building. Now this could be pretty counterproductive
Here are some reasons why this happens.
Improper Peripheral Flashing:
The gaps caused between the wall and the façade due to level differences and alignments could be closed through periphery flashing. It is important to do flashing both from inside and outside, especially outside where flashing has to be inserted into the wall by taking a minimum 2-inch V-groove and thereafter, it should be sealed with sealants. In general, the flashing is done as a butt joint to the wall and sealed. This shall cause water ingress down the line.
Poor Sealants Application on the Joints:
The curtain wall systems available are double and triple barriers systems with Open-Groove and sealed joints. In the open groove system, the gaskets are so designed to ensure the water is drained out without penetrating into the system, whereas in the joints that are sealed through sealants, a lot depends on workmanship and supervision. A failure of this can result in water ingress.
Some other notable and practical points
1.Wear and Tear of Sealants and due to bird biting: In the long run, sealants worn out due to normal wear and tear, excess heat & moisture, improper choice of sealants, bird-biting etc. as a result there could be water ingress in few parts of facade.
2. Weep Holes not provided in the system: This generally happens in cover cap pressure plate systems or in other systems when the fabricators overlook and forgets to provide a weep hole either during fabrication or before fixing the glass, if the weep holes are not provided the water that got into system does not find a way to flow out and constantly travels through capillary action or surface tension, resulting in water ingress.
3. PES: Vent Holes being sealed in Pressure Equalized Curtain Wall by facade cleaning contractor who does not understand the purpose of the Vent Holes, preventing the system from getting pressure equalized and thereby causing water ingress. Though however pressure equalization in curtain wall by itself is a debatable topic.
4. Glass or ACP sizes being smaller than adjacent panels managed with sealants: Due to mass production of glasses and ACP fabrications, due to stiff project timelines, sometimes it may so happen that a few glasses or ACP are of uneven sizes, are not rejected but fixed to the frameworks, neatly managed the smaller sizes through sealants, theses are also the areas of water ingress.
5. Improper Gaskets Designs : Improper Gaskets Designs or Gaskets not fixed properly in the Mullions or sub-frames causing water ingress.
To conclude, it is always better to do complete facade water testing (with adequate pressure) than a selective test that is confined to much smaller portions of the facade. When this is done through rope access specialist these costs are much lesser and its imperative to do the same after major sealant repair works.
Source : CLR, Clean India Journal, Internet