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Why are water-resistant gypsum boards used in kitchens and bathrooms?

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construction of apartment buildings — construction Apartment buildings under construction in Cambridge, England.

Water-resistant gypsum boards, often referred to in the construction industry as "greenboard," are utilized in areas prone to high humidity, such as kitchens and bathrooms, to prevent moisture-related damage.

While standard gypsum panels consist of a mineral core sandwiched between paper layers, water-resistant variants are treated with specific additives to enhance their performance in damp environments. These treatments help the material resist the absorption of moisture, which is essential for maintaining the structural integrity of interior walls in spaces where water exposure is frequent. By incorporating water-repellent substances during the manufacturing process, these boards provide a more durable surface than standard drywall, effectively mitigating the risk of deterioration or mold growth in moisture-prone zones of a building.1

Please note that the term "greenboard" is sometimes used in other contexts, such as to describe a green-surfaced chalkboard, but in the specific context of drywall construction, it refers to these moisture-resistant panels.12