Shanghai, China, is truly a place where East meets West. Symbolic of its mercantile interaction is the Bund, the famous Huangpu business district that is home to European-style structures. Business professionals admire the district's European feeling as a refuge in an exotic city.
When the ultra-luxury Shimao Rivera Garden project was designed and construction began in 2002, its owners had to provide a project that not only mirrored the historical tie to the area; it also had to be durable.
The project is comprised of seven cast-in-place concrete towers, each about 45 stories tall. The original design called for the buildings to be clad with glass and granite stone.
Rivera Garden received strong initial sales response, with apartments pre-sold before construction based on the project's signature style and amenities. But as with many complex engineering projects, managers were concerned about cost overruns during construction.
For the project architect, the challenge was how to value-engineer lower costs into the project while retaining the design's integrity.
Fortunately, staff from Howard Lee-Chin Associates, a project sub-contractor, approached the design team with a unique solution that didn't affect engineering stability or durability. The subcontractor proposed installing BOLDStone architectural natural granite stone finish on the building's upper floors. The solution would leave a hybrid exterior. The first three stories would be clad in granite. But contractors would spray the granite finish coating over the concrete for the highest 42 stories.
The design team found the proposal had merit. The coating's performance reports showed that it met the project's requirements for typhoon-level winds and pollution resistance. But there was another important concern
The biggest challenge for the subcontractor was the requirement to match the granite cladding in color, semi-rough finish, and natural stone-aging.
Working with the manufacturer, Howard Lee-Chin created a custom stone match mix. The recipe included natural granite aggregates for color and its ability to age at the same rate as the natural stone cladding. The formulation resulted in a coating that resists weather, water, UV, mold, mildew, and dirt pickup.
Following approval, the team primed the surface white to help workers visually measure quality control for the subsequent coating application.
Grout lines were extended from the granite cladding by tape-n-void technique over a 1/16-inch base coat of gray BOLDGranite. Two-man crews then sprayed special colored BOLDGranite to 1/8-inch thickness with handheld hoppers. (The manufacturer recommends a commercial pump sprayer.)
Workers immediately back-rolled the finish with a damp foam roller, slightly knocking down the aggregate to match the rough granite finish. They then sprayed on two coats of BOLDTopcoat to further protect the finish.
The subcontractor's biggest surprise was the coating's ability to seam-lessly repair construction damage since the color is the stone aggregate.
A total of 2.7 million square feet of BOLDGranite was applied, with crews averaging 1000 square feet a day. The contractor reported that the flexible stone system material cost was under $5 per square foot.
Using this coating, Howard Lee-Chin delivered the project's stone cladding to the owner at 1/16th the cost of natural stone for a savings of $134 million. Labor costs were reduced 28% and project cladding delivery time by 45%. The result was seven jewel-like stone and glass towers, plus one happy contractor and client.
BOLDBuild develops and provides flexible stone technology and specialty stone and stucco coatings for the North American building materials industry. BOLDBuild's BOLDStone product line has been in service in Asia for 27 years with 55 million square feet installed. For more, visit www.boldbuild.com.