{"id":215625,"date":"2026-10-26T10:00:49","date_gmt":"2026-10-26T14:00:49","guid":{"rendered":"https:\/\/www.constructionspecifier.com\/?p=215625"},"modified":"2026-10-26T10:00:49","modified_gmt":"2026-10-26T14:00:49","slug":"room-to-grow","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/room-to-grow\/","title":{"rendered":"Room to Grow"},"content":{"rendered":"

Like any building material exposed to changing ambient conditions, tile flooring assemblies need room to move. Movement joints (e.g., expansion, control, construction, etc.) relieve stress from thermal expansion in a floor or wall assembly and allow for differential movement between dissimilar materials. When proper movement joints are not provided, the flooring assembly can be damaged by the thermal expansion of the materials.<\/p>\n

In the first project, marble floor tiles were used on an exterior covered porch and terrace of a building in Florida. The tiles were set in a mortar bed, and the narrow joints were filled with mortar. As the paving system expanded under full sun and in hot weather, individual tiles developed chips and spalls along their edges, where the stone was confined by the relatively hard mortar (Figure 1). Cyclical thermal expansion and contraction also caused cracking and the eventual failure of the mortar joints.<\/p>\n

In the second project, red ceramic clay tiles were used as paving for an exterior terrace in the Midwest. The tiles were set in a mortar bed over a structural concrete floor slab, and the relatively wide joints were filled with mortar. Sealant was observed at occasional joints in the assembly, but these were not true expansion joints because they were not continuous through the assembly\u2019s depth and did not extend across the entire width or length of the paved area. During hot weather, the materials expanded, causing several portions of the paving assembly to buckle and heave (Figure 2). With the pavement confined at all edges by the building walls and the parapet, it had nowhere to go but up.<\/p>\n

Guidelines for the design of expansion in paving systems are provided by the Tile Council of North America, Inc. (TCNA), the American National Standards Institute (ANSI), and ASTM International:<\/p>\n