FEATURE: MAPEI mortar brings life to National Shrine's mosaic dome versary, MAPEI provided products to complete the delicate installa- tion of more than 18,300 sq. ft. (1,700 m2 ) of Venetian glass tile. Installation challenge at a height of 159 feet The Trinity Dome is one of the most visually striking and physi- cally extraordinary mosaics in the world, echoing those from the ancient world. The installation process – which featured MAPEI products – also employed age-old techniques, turning the installers into high-climbing artisans. Having previously installed mosaics on three smaller domes within the Basilica, when the crew from Rugo Stone won the bid for the tile installation of the mosaic in the main dome, they immediately began working with the archdio- cese, the architects and MAPEI on a plan to install the soaring artwork in the most unobtrusive manner possible. Being a sacred place of worship, as well as the National Basilica, the church had to remain open during the installation. Further, nothing could fall from the jobsite. At that height, even the smallest tile could be deadly if dropped. So, an elabo- rate safety system was devised. The mosaic fabrication and instal- lation processes were completed using a unique scaffolding sys- tem anchored into the structure of the Basilica itself. The deck/base Rugo Stone team hand-setting the Venetian glass tiles 42 TileLetter | January 2019