During the past two decades one of the most pleasing architectural trends I’ve seen in commercial construction is the increased use of outdoor plazas, planters, fountains and landscaped or “green” roofs. No matter what type of building project, these architectural elements always add a significant feature to a project, especially in major metropolitan cities.
One of the most important considerations an architect, owner or building contractor has to make when planning one of these projects is determining the right waterproofing solution. For buried applications, the waterproofing assembly is an even more critical element in both the design and construction phases due to inaccessibility after the project is complete.
For these types of projects, fully reinforced liquid applied waterproofing systems offer the best long-term performance and adaptability. From extensive overburdens and combining dissimilar materials to submersed elements and very intricate design conditions, these projects including plantings can be a challenge and require a monolithic membrane to bridge all design elements and field conditions. For landscaped or “green” roofing, these systems are a natural solution. The systems fully adhere to practically any substrate. Another key benefit is the superior protection at flashings, seams and transitions; the areas where most waterproofing systems fail. A few high quality reinforced liquid applied systems also withstand bio-deterioration, are root and rot resistant and withstand heavy traffic, pooling water and ice.
For fountain elements the liquid applied systems perform exceptionally well in unique environments like New York City. Clearly, no building owner wants to replace an expensive overburden to correct a waterproofing problem. As a result, fully reinforced liquid applied systems are quickly becoming the standard for plazas, fountains and landscaped architecture.
When looking at liquid applied systems for these types of projects, a key aspect to look at is the reinforcement that creates the membrane. The best reinforcement technology is a high quality polyester fleece for a controlled thickness and strength. Be wary of systems that use random fiber reinforcement and multiple layers of liquid. These systems may be good for surfacing, but they just don’t offer the long-term performance of a fully reinforced system.
For sensitive interior applications including gardens, fountains and planters, many systems are now environmentally friendly. It may take a little research, but finding waterproofing and roofing systems that are odorless, solvent-free, Ultra Violet (UV) resistant and with low VOC is possible. Using a fully reinforced waterproofing system will ensure the long term success of your most challenging projects.
Case Study: Empire State Building, New York City
Standing the Test of Time – Metal Roofing Problem Free Since 1992 Installation
After experiencing multiple breakdowns and years of leakage of previously installed products of the dome and promenade, the building owners committed to employing the best possible materials to protect the millions of dollars of highly valuable and sensitive broadcasting transmission equipment housed directly under the dome itself serving the New York Area.
Due to the project’s extremely challenging logistics of accessibility, which required a complicated scaffolding system, the building owners selected a monolithic, cold-liquid applied, fully-reinforced high quality, waterproofing and roofing membrane.
The criteria for its selection was determined by its ability to:
- Provide a fully seamless encapsulation of the entire sheet metal panel surface incorporating all the penetrations of the antennae equipment and numerous penetrations.
- Prevent the negative effects of Ultra Violet (UV) exposure. (Being 1200 feet above sea level the UV exposure was much stronger than at ground level.)
- Withstand extreme dimensional changes in expansion and contraction due to extreme climatic exposure because of the concrete construction and a strut framing system that carried a sheet metal panel assembly cover with multiple fasteners and loose laid lap seams every two feet.
- Adapt and conform to multiple configurations and penetrations while being applied.
The project required extensive substrate preparation and repair of the existing sheet metal dome to ensure its integrity to the concrete substrate. Next was the application of the priming system to accept the membrane. Due to the intense UV exposure care had to be taken not to expose the primer system to UV which would cause a breakdown in adhesion of the membrane over time.
Once the membrane installation was complete the dome required a single component urethane coating which required inspection and acceptance for color by the New York City Landmarks Commission because the Empire State Building is a protected landmark structure.
The result was a complete encapsulation of the mooring tower consisting of stainless steel sheathing with multiple seams and fasteners. The project also incorporated flashing of multiple antennae penetrations with entire membrane application which swayed eight inches to each side during wind conditions.
For more than 15 years the cold-liquid applied, reinforced application system has performed flawlessly and all signs indicate that it will exceed performance expectations for many years to come.
About the author: Steven Cortazzo has been in building, construction, and product development for 37 years and is president and CEO of Kemper Systems Inc., which specializes in waterproofing and roofing technology. He can be reached at scortazzo@kempersystem.net..
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