performance bond. This two-part system provided exceptional bond strength, flex- ibility and elongation. A flexible yet strong mortar was imperative, as failure was not an option. The specified mosaic embellishment consisted of 14 million pieces of specialized Venetian glass, total- ing 24 short tons (21.8 metric tons) of tile across 18,300 square feet (1,700 m2 ) of the dome. First, the Rugo Stone team completely FEATURE: MAPEI mortar brings life to National Shrine's mosaic dome The completed Trinity Dome in the Basilica of the National Shrine of the Immaculate Conception Intricate details within the church 44 TileLetter | January 2019