What is Gypsum Sheathing?

Gypsum sheathing may better be known as drywall. Drywall, or gypsum sheathing, is used nearly specifically in the construction of wall in homes and buildings. Even though gypsum sheathing is used all the time most people know little about it. The article that follows will help to explain what gypsum sheathing is, how it is used, what it is made of and other details.

Other Names for Gypsum Sheathing

In the construction industry you will often find products that are the same but will have several different names associated with them. Gypsum sheathing certainly is no different. In addition to it being known as drywall it's also known as sheetrock. It can also be known as exterior wall board.

The Uses of Gypsum Sheathing

The material is often used as an inside wall covering in the form of drywall. Gypsum sheathing can also be used as an exterior underlayment. The exterior variety is resistant to water and is affixed to the exterior wall. It is not meant to be painted or used as an exterior wall but as a base for one. Wood, vinyl and metal siding can be attached to exterior gypsum sheathing. Shingles, masonry veneer and stucco can also be attached. Exterior gypsum sheathing is made with a water-resistant core that has been treated with wax. Paper that repels water is then applied to the sides, front and back of the gypsum sheathing. Interior gypsum sheathing is covered with a layer of thick on both sides and is used to cover wall frames.

What Gypsum Sheathing is Made Of

The actual name of gypsum is calcium sulphate dihydroxide but it is also known as sulphate of lime. You will typically find gypsum underground and close to limestone deposits and other minerals that have formed due to evaporation. Alabaster is a common pure form of gypsum which is a pure white crystal substance. The harsh and dry desert terrain can also form gypsum. The crystals formed in this manner have the look of a petal and is commonly known as "desert rose".

Other Uses

Gypsum is bound chemically to water and is heated to remove moisture. The powder that is created from this process is known as "burnt gypsum". The color does not change despite what the name implies. Adding water to burnt gypsum will cause it to harden. It is used in plaster of Paris as a molding agent but many school children will best know burnt gypsum as chalk. Gypsum is used as a way to strengthen soil and is used often by gardeners that have too much clay in their soil. Cement also utilizes gypsum.

Types and Sizes

Gypsum sheathing is manufactured to certain styles and size standards. Exterior gypsum sheathing is often 1/2-inch thick and 2-feet wide. This variety is also manufactured with an edge that is tongue and groove style. You can also find the sheets in 1/2-inch and 5/8-inch thick with a 4-feet wide edge. The interior gypsum sheathing is found in 24-inch and 48-inch wide sheets that are 8-feet or 9-feet long.