Critical to parking structure performance and longevity is effective deck expansion joint sealing. Even more critical than watertightness of joints is
Critical to parking structure performance and longevity is effective deck expansion joint sealing. Even more critical than watertightness of joints is a parking deck design that incorporates a structural slab waterproofing membrane under a wear-course or topping slab. The emergence of a watertight, purpose-designed system has provided designers an alternative to the buried, looped-membrane method.
Emseal’s Migutan joint-sealing system especially suits applications, particularly over occupied space, where watertight integration of expansion joint and deck membrane is a fundamental requirement, as in split-slab construction on plaza or podium decks. Its design incorporates side membranes that integrate with deck waterproofing to form a continuous, watertight system.
Positive interlocking, heavy-duty aluminum side rails eliminate misalignment between adjoining sections; and, stainless steel, gland-retaining capping strips allow long-term maintenance access. Unique to Migutan are sealing insert and side flashing sheets constructed of heat-weldable thermoplastic rubber (TPR), which ensures continuity of seal at terminations and through transitions in plane and direction.
Tees, crosses, directional changes, column details, terminations, and changes in plane are available as factory-fabricated assemblies. Leg heights from 1 in. (25 mm) to 12 in. (400 mm) accommodate pavers, asphalt and other toppings.
Purpose-designed, watertight, parking, plaza, garden-roof and roadway joint systems have been specifically engineered to address other methods’ shortcomings, Emseal officials contend. The Migutan system illustrates how a split-slab design, involving static-membrane integration with a positively anchored movement gland, achieves watertightness.
Principle of operation
Split-slab parking or plaza deck waterproofing entails the application of a membrane to a structural deck and covering it with a topping or wear-course like asphalt, lightweight concrete, or pavers. Porous by design, the topping allows water to reach the membrane on the slab, where it is managed to drains. When expansion joints are necessary, they must be waterproofed using a method and material that accommodates movement while reducing or eliminating the stresses that will cause a buried membrane to fail.
Accordingly, the Migutan design provides static integration of the joint system with the deck waterproofing membrane. In addition, it incorporates a heavy-duty gland to accommodate movement at the joint fully integrated with the deck-waterproofing tie-in, but also accessible for repair, if necessary, without disruption of the topping system.
Composition
The Migutan system employs a combination of corrosion-free, aluminum and stainless-steel mounting rails mechanically secured to the structural slab to provide positive anchoring of waterproofing components. Tension, compression, torsional, and other forces resulting from joint movement are thereby isolated from the critical connection of the deck waterproofing membrane to the side flashing sheets of the joint system.
Thermoplastic rubber materials comprise the waterproofing components. To produce transitions for addressing changes in plane and direction, these materials can be heat-welded in the factory; they can also be welded in the field to address situations as they arise, using hot-iron tools to attach transitions to straight runs.
The buried, band-aid solution usually requires a simple piece of EPDM thermoset rubber. Lacking the mounting components of the Migutan design, it does not provide positive mechanical anchoring of the system. Further, no barrier exists between the strip and deck membrane at the point of adhesion to isolate tensile stresses caused by joint movement.
Track record
In over 20 years of waterproofing plaza and split-slab deck, parking decks, stadium concourse, garden roof, and roadway expansion joints, Emseal representatives affirm, specialty waterproofing contractors under the guidance of qualified field technicians have installed thousands of feet of the Migutan system for satisfied owners. The fully warranted installations have been integrated primarily with hot-rubberized asphalt waterproofing membranes.
According to Migutan developers, using a joint-system integrated into the waterproofing membrane on the structural slab ensures long-term watertightness for new and retrofit applications. Toronto’s CarPark 11 demonstrates the benefits of this type of system, including the elimination of concrete curbs that are subject to cracking and accessibility issues tied to sealing gland repairs or replacement. Û 800/526-8365