Case 3
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- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Cause of Defects
The window leak water because they leak too much air, which drags the water in through capillary action due to difference in pressure with the exterior.
Weakness in the window system design:
- Seal between the end of the transom and the mullion is too thin (2mm). This barrier seal is unable to withstand the full pressure of the wind load and overtime its failure will allow water penetration into the interior.
- Waterproofing system for the mullion is not continuous at the spandrel and allows water to get into the mullion and drip onto the bracket and the head of the timber trim. Although this problem has been foreseen and addressed by face sealing the mullion, this is not effective since the joint in the front of the mullion is too small to be sealed.
- The wet-seal gaskets are on the outside rather than the inside. The interior gaskets forming the air seal is also not continuous and allows air to infiltrate through the drain holes.
- The gaskets at the rear of the opening sash is also not continuous, not compressible and quite hard. It does not form an air seal and allows air to blow through and drags water in.
Consequences
The present system of waterproofing cannot provide the required guarantee of 10 years non-leakage. Both air and water leakage to the interior of the hotel rooms are not acceptable to the hotel guests.