Drywall is a building material made from sand, water, and gypsum. This product is one of the most widely used products in the world for building walls, ceilings, and other architectural features. Sheets of drywall are installed using screws to fasten them to the building's framing members. Installers will then finish the surface of the drywall to give it the desired appearance. Drywall finishes come in a number of different varieties, which can be categorized as either smooth or textured.
Smooth drywall finishes are installed in accordance with the standards developed by the US Gypsum Association under document GA-214-96. These standards reference six levels of smooth drywall finishes, and are considered the industry standard in the North America. This system not only allows drywall companies to provide accurate estimates, but also helps facilitate communication with installers, leading to more accurate results.
For temporary walls, or when the final desired finish is unknown, a Level 0 finish is used. At Level 0, the sheets of drywall are installed without the use of tape or joint compound. Level 1 drywall finishes are designed for walls that are hidden from sight, and feature a layer of drywall tape embedded in a single layer of joint compound. A Level 2 finish is virtually identical to Level 1, and is used when appearance is not a concern. Again a single layer of tape and joint compound is used, though fewer tool marks are permitted.
A Level 3 drywall finish is used for walls that will be exposed to public view, but will also be covered with thick or matte paints. Level 3 walls feature embedded tape along with two coats of drywall or joint compound. The standard smooth drywall finish is a Level 4, which includes three coats of joint compound over tape, with walls sanded smooth. For areas exposed to bright or harsh lighting, or those used with high gloss paints, a Level 5 finish is recommended. This finish includes all features of a Level 4 installation, along with a skim coat of joint compound across the entire wall.
Textured drywall finishes vary from low to high textures, and can be installed using sprayers, trowels, paint rollers, or a combination of these tools. Some of the lowest texture finishes are swirl patterns, where a trowel is used to apply joint compound in an overlapping swirls, similar to the scales of a fish. Medium textures include Perlite, with small foam or sand particles sprayed onto the wall, or Slip-Trowel, which features raised spots on the wall that resemble spalling concrete. Highly textured drywall finishes are usually sprayed on, and include Orange Peel, which is bumpy like the skin of an orange, or acoustic popcorn, which is used to create thickly textured drywall ceilings.