Flood testing using ASTM D5957-98, Standard Guide for Flood Testing Horizontal Waterproofing Installations, is a good method to verify the continuity of the waterproofing membrane. This test suits parking decks since they mostly have a slope of no greater than two per cent with a liquid-applied, adhered, or loose-laid waterproofing membrane. Testing is best performed for a minimum of 24 hours and a maximum of 72 hours, when rainfall is not expected. If failure occurs, the tested floor will be drained and the breach will be mended, and retest will be performed as well, using the same conditions. Required preparation work includes installing containment assemblies and plugging the drains with inflatable devices consisting of rubber balls, draw chains, and rings, as well as other standard plumbing fixtures.
As an alternative to flood testing, utilizing electric leak detection (ELD) to test the integrity of the waterproofing membrane is safe, fast, accurate, and economical. ASTM D7877-14, Standard Guide for Electronic Methods for Detecting and Locating Leaks in Waterproof Membranes, and ASTM D8231-19, Standard Practice For The Use Of A Low Voltage Electronic Scanning System For Detecting And Locating Breaches In Roofing And Waterproofing Membranes, describe standard procedures for using electrical conductance measurement methods to locate leaks in waterproof membranes. This method is suited for a typical parking deck, where the concrete acts as a conductor and the adhered membrane is the electrical insulator. When there is a hole in the membrane, a breach will be detected to determine the hole’s location. Low-voltage-vector-mapping, high-voltage ELD, and low-voltage ELD can be employed on most waterproofing membranes for leak detection and QA. (See Figure 3)
Conclusion
Parking decks are harmfully affected by wear, abrasion, aggressive chemical agents, damaging environmental agents, extreme temperature variations, rough use, salt, and water intrusions. Ignoring a small water leakage into the assembly may lead to serious and costly structural deficiencies and catastrophic failures in extreme cases. Taking preventive measures would increase the service life of parking structures and reduce disruptive and expensive repair. Additionally, applying lessons learned from maintaining and repairing aging parking garages would help to design practical and durable structures. The Parking Facility Maintenance Manual by the National Parking Association (NPA) is a valuable guide to extending the lifespan of parking garages through site-specific maintenance and repairs.
Author
Amir Hassan has more than 25 years of experience with building envelopes and forensic restoration in the Middle East, Europe, and North America. He has worked on complex projects for both existing buildings, including historical and heritage buildings, and new construction. His building science knowledge includes work with structural glass, curtain wall design and evaluation, frameless and skylight systems, structural assessment
and repair, property condition assessment, building enclosure commissioning, roofing and waterproofing systems, weather tightness, energy modelling, thermal performance, and thermography. Hassan has a Bachelor of Science
in civil engineering and a Master of Science in facade engineering. He is a frequent speaker and author, covering roofing and the building envelope. He is the current president of Alberta Building Envelope Council North (ABECN). He also holds the role of subject matter expert in the field of building science with the Association of Professional Engineers and Geoscientists of Alberta (APEGA). Hassan can be reached at amir.hassan@exp.com.
