Like most innovations and inventions, rigid cement backer boards were born out of necessity. Historically, builders would use drywall or wood to support tile installations because these two materials proved to work well at first, but they inevitably failed over time. Continuous exposure to water can be lethal for drywall and detrimental to wood, yet in certain areas of the home like kitchens and bathrooms, water contact is unavoidable.
Drywall can fail in wet areas because it is made of gypsum, a soft sulfate mineral that loses strength when it absorbs water. Over time, the drywall’s integrity is compromised and the strength of a tile-install base is severely weakened. Furthermore, the paper face of drywall is an organic substance and a viable food source for mold and mildew. Wood’s structural integrity is vulnerable to water as well. Exposure to water over time can drive up the moisture content in the wood to its fiber saturation point, potentially leading to swelling, shrinking and decay, which can cause structural damage.