Drywall photos are straightforward and boring but the decision to use drywall was complicated. Drywall is gypsum board and it is fabricated from both naturally occurring gypsum, which is a mineral, and synthetic gypsum, which is a power plant byproduct. It comes with new paper backing, recycled paper backing, or embedded fiberglass threads, and some versions are treated with chemicals that act as fire retardants, mildewcides, etc. Both natural and synthetic gypsum emit very low levels of mercury, to which I am allergic when used as a preservative, and if there is water damage the paper backing can become a breeding ground for mold. I initially decided to use magnesium oxide board, which is marketed as a green alternative to drywall. However, I changed my mind after reading this article about Denmark’s experience. Ultimately I opted for untreated drywall. My house should have excellent moisture control and any trace amounts of mercury should be below outdoor levels, to which I don’t react.
