The question is asked all the time about whether flooding or water leaks will ruin the drywall in our home? The short answer is yes, it will. Drywall water damage is quite a common result of leaking and flooding.
Drywall is called by several names. It may be called gypsum board because of the main ingredient, gypsum. It may also be called Sheetrock, which is actually a product name. Sheetrock was a product developed by the United States Gypsum Company in 1916. It was developed to be an efficient alternative to hand plastering after World War I, mainly because of the boom in the housing industry after the war.
Drywall is composed mainly of gypsum that has been manufactured into a powder form. Small bits of paper, cotton, fiberglass and other chemicals may be added to the powder to enhance its strength, facilitate manufacturing and add fire or mildew resistance. This powder mix is then turned into a slurry by mixing it with water. After the slurry has been applied to its paper backings and pressed into shape, it is cured in an oven. The drywall retains some water content for flexibility and a measure of fire resistance.
Once the drywall has become saturated with water, its composition begins to deteriorate, rendering it unusable. The interior begins to crumble and the drywall will literally fall apart. Additionally, the paper outer coverings will begin to mildew, promoting the growth of bacteria, mold and other health hazards.
The extent of the drywall water damage depends on how quickly the leak is discovered and repaired, along with the location of the damage. Water-damaged drywall cannot be repaired; it can only be replaced. If the damage is from a roof leak or flooding, all of the affected drywall will probably need to be replaced. The wooden framework to which it is attached is the load bearing structure, so drywall removal will not weaken the structure.
Plumbing leaks that are located close to the floor may only damage the bottom of the board; therefore, removal and replacement of just the damaged section may be possible after the leak is properly fixed. In any event, drywall water damage must be handled quickly to prevent air and surface contamination and the resulting health hazards that are possible.