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ASCR Technical Library
Can this Drywall be Saved – WLI Moldy Drywall Study Completed
Article 1058
Topic: Antimicrobial Treatments
Author : Pearce, M.
Date/Pages Mar 1999 pp.22-24
*** Please Note:
The information presented in Cleaning and Restoration is designed to provide accurate information in regard to the subject matter covered. However, information may change and circumstances may vary. In no event will ASCR International or the authors of these articles be held liable for any direct, indirect or consequential damages, including damages for any cleaning and restoration work, resulting from the materials or information presented in Cleaning and Restoration.
Excerpt:
Introduction
Every year, billions of square feet of drywall are hung in homes and buildings. Durable and long lasting, drywall, also known as gypsum board or sheetrock, is used for finished walls and ceilings, exterior sheathing and as shaft liner. Drywall provides both structural strength and a smooth surface that can be finished with paint, tile, wallpaper or vinyl wall covering.
The principal enemy of gypsum board walls is moisture. When water soaked for an extended period of time, drywall turns to mush. The paper coatings separate and the gypsum inner core loses its structural integrity. Less severely wetted walls are often dried and restored. Unfortunately, wetted drywall can be an ideal habitat for mold. Molds feed by secreting digestive chemicals into their environment, and then reabsorbing the digested material as food. The molds digestive enzymes require water to be chemically active. The paper coating on drywall has a high cellulose content, and many common molds have the ability to thrive on cellulose if it contains sufficient moisture. While there are many variables, it seems that mold takes about three to five days to become established on damp drywall. Once established, the colonies will continue to grow and thrive as long as the material remains sufficiently damp. As the wall dries, mold activity ceases and the colony becomes dormant. Dormant colonies may remain viable for years, and will readily resume activity when exposed to more water or very humid air.
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