When expanding this Texas medical center, the design-build team incorporated the extruded silicone sheet, Spectrem Simple Seal, to connect the precast panel and metal panels with a flexible, air- and water-tight solution.
In late 2017, less than three years after University of Texas Southwestern Medical Center’s Clements University Hospital in Dallas was dedicated, the system broke ground on a significant expansion, which would add a third tower to the existing building.
Houston-based glazing firm Dynamic Glass was contracted to fabricate and install roughly 110,000 square feet of glass, about 80,000 square feet of it being pre-fabricated ribbon windows and the remainder unitized curtainwall as well as some stick-built areas. During a page-turn meeting early in the project, the consultant expressed concern related to a transition of the curtain wall system assembly to the precast panel. There may have been a gap for air flow at this transition and wanted shop drawings to incorporate an extra measure of protection to seal any gaps below the sill track. There was even more concern pertaining to air flow and the possibility of condensation through the gap transferring to the inside of the building.
“The consultant’s concerns pertained mainly to air flow and the possibility of condensation through the gap transferring to the inside of the building,” explains Dynamic Glass Senior Project Manager Edward Longard. “Any air infiltration there could lead to condensation on the sill member.”
The curtain wall design included prefabricated ribbon windows going into precast punched openings with an embed in place. Longard elaborates, “There was a legitimate gap in scope. Typically, the architect would have drawn something in the detail that they wanted, instead of deciding later down the road and requiring us to come up with a solution.”
To address these concerns, Dynamic Glass worked with the consultant to incorporate a solution that would cover the air gap. It would need to adhere to and be compatible with the silicone sealant and be easy to install. Options included a mill finish break metal or extruded silicone bridge.
Tremco recommended Spectrem Simple Seal a silicone extruded sheet in a 3" width, adhered with silicone sealant to the precast panel on one side and the metal panel connection on the other.
“While we could have gone with a break metal there, Simple Seal was the most physically flexible and the easiest product for us to use. We were able to easily cut it to length...You run your sealant lines and then you just bed it down, and you’re ready to install the sill track on top of it,” Longard states.
