There has been considerable discussion concerning the need for movement
\njoints in tile assemblies. The question is not whether they are needed;
\nthat is a simple yes. The questions are \u201cWhere do they go?\u201d, and \u201cWhat
\nis used to fill the joint in the tile assembly that will control or compensate
\nfor movement in the entire assembly?\u201d There are several different types of
\nconstruction movement joints defined by the Tile Council of North America
\n(TCNA) that are needed in tile assemblies:
\n\u2022 Construction \/ Cold Joints are formed between two successive placements
\nof concrete. Quite often the reinforcement in the concrete will continue
\nthrough the two successive placements.
\n\u2022 Contraction \/ Control Joints formed in the concrete or sawn into the cured
\nconcrete. This creates a weakened plane in the concrete that regulates
\nthe location of cracking from natural movement during the curing cycle.
\nThe concrete will crack the same as the random cracks we commonly
\nobserve in concrete slabs, except with the inclusion of control joints, this
\nrandom cracking is controlled to a specific location. There is a potential for
\ncontinued movement that will cause these cracks to open and close the
\nsame as the unrestricted natural cracks that occur randomly.
\n\u2022 Expansion Joints are created in the concrete to compensate for excessive
\nexpansion, due primarily to temperature changes in the concrete. As the
\nconcrete cures it generally will shrink and as the temperature raises the
\nconcrete and tile assembly will expand. When the expansion exceeds the
\nshrinkage the concrete needs a joint to compensate; if not it can bend and
\ndome slightly, resulting in cracks in the assembly<\/p>\n","protected":false},"excerpt":{"rendered":"