In summer 2023, a Costco warehouse in the North West of England experienced significant issues with their siphonic drainage system during intense rainfall. This prompted a systematic review of multiple UK locations.
The assessment revealed that Costco’s buildings had primary-only siphonic systems designed to handle day-to-day rain events but lacked secondary systems for extreme rainfall. These systems were designed according to rainfall standards in place at construction time but were no longer adequate for current weather patterns.
Services included;
The Solution
NSS implemented a comprehensive upgrade programme that included:
- Enhanced gutter protection using specialised cold-applied PMMA liquid system encapsulation
- Supplementary secondary systems for valley gutters to align with current standards
- High-level overflow systems for internal eave gutters
- Emergency overflow indicators to signal potential drainage issues during regular rainfall
The upgraded systems now handle 100mm/hr rainfall, exceeding Category 3 protection in today’s standards and future-proofing the buildings against increasing rainfall intensity.