Below-Grade

Below-Grade Parking Facilities Summary

While they provide security and convenience for tenants and visitors in commercial and residential buildings, below-grade concrete parking structures present a number of waterproofing challenges. Leakage is always a concern, particularly if the local water table is high or there is significant hydrostatic pressure. Corrosion of steel reinforcements due to sulphates, chlorides and other waterborne chemicals can also be a problem. And given that the structures are often completely sub-grade, cracking and leakage can be difficult and expensive to repair.

In the past, below-grade parking structures were waterproofed using external membrane systems. However, membrane systems can be expensive and difficult to install, especially if neighbouring buildings limit access to the structure's positive side. Membranes are often damaged during backfilling and will eventually deteriorate, leaving structures and reinforcements unprotected and requiring expensive repairs.

Kryton International's KrystolTM Concrete Waterproofing System overcomes many of these challenges and provides permanent, worry-free waterproofing for concrete parking structures. Based on Kryton's proprietary Krystol technology, the system includes:

• Krystol Internal Membrane (or KIM), an admixture for new concrete construction
• Krystol T1/T2, a surface-applied system for repairing & waterproofing existing concrete structures, and
• The Krystol Waterstop System to protect and waterproof concrete construction joints.

When added to a concrete mix or applied to existing concrete, Krystol creates a chemical reaction that causes needle-like crystals to grow, filling the spaces between concrete particles and permanently blocking the movement of water in all directions. If small cracks later form, incoming water causes additional crystals to grow, self-sealing the cracks and stopping the movement of water through the concrete. Krystol - treated concrete is also proven to resist up to 460 vertical feet (140 metres) of hydrostatic pressure.

The Krystol system blocks the migration of water and safeguards steel reinforcements against corrosion for the life of the structure. Impervious to physical damage, the ability of Krystol to self-seal small cracks reduces maintenance and repair costs. By eliminating the need to leave room on the positive side for membrane application, Krystol allows structures to be built right to the property line, even where there are abutting buildings.

Intrawest Employee Services Building, Whistler, B.C.
One of the major concerns with this below grade parking structure built into the side of a mountain was the large amount of run-off, which would create significant hydrostatic pressure and increase the chance of leakage into the parkade. To fortify the 3-meter-tall foundation walls and form a permanent, watertight barrier able to withstand the run-off, the designers and builders chose to use the KIM admixture in the walls and suspended slab and the Krystol Waterstop System to seal and reinforce concrete joints. To date, the system is performing as specified.

Shaw Tower Parkade, Vancouver, B.C.
Located in Vancouver's Coal Harbour neighbourhood, the Shaw Tower is the city's tallest building. Unfortunately, its prime location at the water's edge made water intrusion into the 5-level underground parking lot a major concern. At high tide, groundwater rises 3 feet above the lowest parkade level, more during extreme tides and adverse weather conditions. The high salt content in the soil and groundwater also posed a threat to the structure's steel reinforcements, and existing structures abutting the basement made installing an external waterproofing membrane difficult and costly. Foregoing conventional external membranes, the designers and builders instead chose to use Krystol Internal Membrane (KIM) admixture in the underground portions of the concrete parkade. Results to date have been excellent, and the minor cracking that did occur was rapidly repaired by the Krystol technology's self-sealing ability.

St. Kilda Beach Parkade, Melbourne, Australia
When designing this 460-car underground parking lot, the project team was concerned about the structure's proximity to the beach and the corrosive effects of salt water and other contaminants on the concrete's steel reinforcements. Also, since the parkade would be covered with landscaping, access to the positive side of the completed structure to repair cracks or leaks would be near impossible. Krystol's life-long permanence, superior corrosion protection and ability to self-seal cracks and reduce the need for repairs were just what the team needed. Thirty-seven-hundred m3 of KIM-treated concrete were used in this structure that today is leak-free and functioning well.

Sandestin Golf and Beach Resort, Sandestin, Florida
As part of a major expansion at the Sandestin Golf and Beach Resort, several large water features including a swimming pool, hot tub and in-ground irrigation system were planned for the area directly above the resort's two-level parking structure. Protecting the parking lot and staff and guest vehicles from water or waterborne chemicals was vital. After researching various options, the project team chose the Krystol system to supplement and fortify their conventional waterproofing systems. Krystol Internal Membrane (KIM) was added to the concrete pour for the parkade roof slab, and concrete joints were sealed and reinforced with the Krystol Waterstop System. More than 4,000 yards of KIM concrete were used in the project and despite some early, isolated leakage problems with the water systems, the parkade remains leak-free.

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