What is the difference between drywall and plaster?

Inside Drywall
This drywall is ready for some paint.
This drywall is ready for some paint.

For basic gypsum drywall, the calcined gypsum is mixed with water and occasionally additives to create the core material [source: Gypsum Association]. The viscous material is then squeezed, or flattened, between two different layers of paper and dried. One side of the paper is the face, which is strong and smooth, while the other side, or back, has a rougher texture [source: Ferguson].

Installing drywall is a fairly quick process compared to that of plastering. The boards are cut to fit the shape of the walls. They're then secured to the rough framing of the house. After the boards are in place, corner bead is attached to the corners to give them a straight edge. The walls are then taped with either paper or fiberglass-mesh tape at the joints, corners and places where the boards have been fastened to the wall. Then, the typical three layers of joint compound are added. After each layer, the wall is sanded to give a smoother surface. Once the third layer had dried, the wall is ready to be painted.

There are obvious advantages to drywall over plaster. First, the process of installation requires less time and labor, which can translate to less cost. Drywall also helps to reduce noise along with having fire-resistant properties due to the water in the boards.

While drywall does have many advantages as an interior wall material, it's not invincible. Drywall can be damaged by the settling of the building or homeowner accidents. A common problem is nail or screw pops, when the head of these fasteners creates a bulge or becomes visible through the drywall.

Secondly, gypsum drywall is susceptible to water damage if exposed to elevated levels of moisture over long periods of time [source: Gypsum Association]. There are specialty drywall boards with additives that are designed for better water-resistance.

Along with water sensitivity, gypsum drywall boards can have mold problems. To decrease the chance for mold, new gypsum drywall boards are going paperless.

Whether you choose the versatility of drywall or the old-world charm of plaster walls, interior walls shape the look, flow and feel of your home. Knowing about the advantages and disadvantages of both plaster and drywall help you to choose the best system for your lifestyle.

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