In a bonded tile installation, cracks in the substrate can easily mirror through to the tile. A decoupling membrane is installed between the subfloor and the tile with a specialized mortar bond. The membrane features a geometric structure that provides in-plane movement, effectively 'decoupling' the layers. This prevents the transfer of shearing forces from the substrate to the tile layer, significantly reducing the risk of cracked tiles or grout, especially on challenging substrates like plywood or concrete slabs prone to shrinkage.
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How do decoupling membranes interact with tile and substrate movement?
Decoupling membranes are designed to isolate the tile assembly from the substrate. By allowing the substrate and the tile to move independently in the horizontal plane, these membranes prevent the stresses of subfloor contraction or expansion from transferring directly to the tile surface.