Gypsum is the result of the evolution of the building industry. For thousands of years, plaster made from lime, sand, animal hair and other ingredients was used to create a smooth interior finish. Later, it was discovered that gypsum dried faster than lime, so gypsum became the main ingredient in plaster. It wasn’t until well into the 20th century, though, that sheets of plasterboard began to replace traditional wet plastering.
Today, gypsum boards comes in standard sizes and thicknesses. The gypsum sheets used in Nairobi offices are usually 2.4 Metres long by 1.2 Metres wide – the same as a standard sheet of plywood or particle board. The sheets are heavy and brittle and care must be taken when handling them. Straight cuts can be made in gypsum simply by scoring through one outer paper layer and snapping off the unwanted excess.
Gypsum boards is applied to walls and ceilings using special drywall nails or screws, which penetrate the gypsum without shattering it and hold the heavy sheets firmly with their wide heads. Gypsum nails and screws are sunk just beneath the surface of the Gypsum. After it is installed, the indentations and seams are filled using special plastering products applied with a trowel
Gypsum revolutionized the way walls and ceilings are covered. Before the 1950s, when these paper-wrapped gypsum panels came into widespread use, it took days for lathers and plasterers to create a firm, flat foundation for paint or wallpaper. With gypsum, it takes a fraction of the time. Two pros can typically cover a 12-by-16-foot room in about an hour.
To work that fast takes practice and a few specialized tools. But hanging a gypsum is not just about speed. Doing the job right means using screws of the correct length, off-setting panels so seams don’t line up, and making sure wires and pipes aren’t vulnerable to puncture.
Most often called drywall or plasterboard in Nairobi, gypsum is one of the world’s most common building materials. The majority of offices in Nairobi that are not brick clad have gypsum interior ceilings and even most brick homes or offices have gypsum ceilings and some gypsum walls.
Water damage and mold
Gypsum board may become damaged when exposed to water, especially if the gypsum remains exposed to the water for an extended period of time. Often, when a room features gypsum installed and an unintended introduction of water occurs and the water comes into contact with the gypsum at the base of the wall where the gypsum touches the ground, wicking will occur. Capillary action may introduce moisture anywhere from several inches to several feet above the floor depending upon the length of time the wall is exposed to water and how long the gypsum remains in contact with the water supply.
Water that enters a room from overhead may cause ceiling gypsum tape to separate from the ceiling as a result of the grooves immediately behind the tape where the drywall pieces meet become saturated. The drywall may also soften around the screws holding the drywall in place and with the aid of gravity, the weight of the water may cause the drywall to sag and eventually collapse, requiring replacement.
In many circumstances, especially when the gypsum has been exposed to water or moisture for less than 48 hours, professional restoration experts familiar with structural drying methodologies can introduce rapid drying techniques designed to eliminate necessary elements required to support microbial activity while also restoring most or all of the gypsum and thus avoiding the cost, inconvenience and difficulty of removing and replacing the affected drywall.