Drywall Basics: Measuring, Prep and the Different Types

Learn about they different types of drywall, how to determine how much you'll need and the best ways to prepare for the job.

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Related To:

  1. Drywall
  2. Installing
  3. Walls

Drywall has Gypsum Core and Paper Backing

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Drywall is the standard wall covering in the United States, covering three out of four interior walls in our homes. While it takes practice to properly finish drywall, it does not require many tools and is fairly straightforward. If you are planning to alter or build any walls in your home, you will need to know the basics of drywall.

Drywall Basics

Drywall is a specific type of sheeting material made of gypsum sandwiched between paper. Also referred to as wallboard, plasterboard, or gypsum board, drywall started to replace plaster as the typical interior wall finish in the United States more than 60 years ago. It is less expensive than plaster, and much easier to attach to stud walls. The panels are typically screwed to wall studs and the joints between panels are filled with joint compound, which is then finished to a flat surface.

Plastering

  • If you have a home built before 1950, you may have plaster walls.

  • Plaster is heavy, and it needs a solid, well-anchored base made of strips of wood or metal wire, called a lath, to support its weight.

  • Over time plaster can dry out and lose its holding strength, or the lath beneath can pull away from the framing. If you see your plaster walls sag, you may need to repair them.

Plastering and Drywalling Options

Plastering a masonry wall
A traditional method for preparing a large area of wall, ready for decorating (Image 1).

plaster masonry diagram

©2007 Dorling Kindersley Limited

2007 Dorling Kindersley Limited

Plastering a stud wall
A smooth finish over untapered board, achieved by plastering across the entire surface (Image 2).

plaster stud wall diagram

©2007 Dorling Kindersley Limited

2007 Dorling Kindersley Limited

Drywalling
Layers of compound fill the joint, which is then sanded to provide a smooth finish (Image 3).

drywalling diagram

©2007 Dorling Kindersley Limited

2007 Dorling Kindersley Limited

Preparing to Use Drywall

Drywall developed as an alternative to plastering walls. Some say the name drywall is characteristic description of the material. Unlike the plaster-and-lath wall surface that is completely moist and must be left to dry, drywall only has its joints that are moist from joint compound and they dry much more quickly than plaster.

Even with the benefits of drywall installation and repair over plastering, you still may decide to take on plaster repairs if you live in an older home or if you are restoring a home to its original materials.

Before you even begin to drywall or plaster your walls, make sure you have a flat working surface. When taking on the task of drywalling your home, the most important objective is to achieve a smooth finish. Each step in the multi-step drywalling process is designed to help you achieve this. The first part is making sure your stud walls are framed correctly. If the walls are not flat, the drywall panels will show the imperfections. It will be very difficult to overcome this type of imperfection through finishing techniques. It must be fixed prior to drywalling.

Drywall Materials

Drywall is available in 4' and 4-1/2' widths, and ranges in length from 8' to 16'. Due to the rectangular shape of the pieces, it is recommended that you hang the sheets parallel to the floor to reduce the amount of finishing work required. You will save time and money on the tape and joint compound needed to finish a larger number of vertical seams. If you are able to transport the larger-sized sheets, buy sheets that are the width of the wall, if possible. This will further reduce the amount of taping required.

Measuring for Drywall

When planning to use drywall materials, first determine the total square footage of the walls and ceiling that you are aiming to cover. Include the window and door openings, and always estimate high. Never buy exactly what you think you may need to just finish the project. This will save you time spent traveling back and forth to the home center during the project.

If you are using the standard 4' x 8' sheets of drywall, divide the square footage number by 32 (4 x 8 = 32). This will provide an estimate of the number of sheets you will require. You will also need about 400 feet of tape for every 1,000 sq ft of drywall. And you will need about 150 lb of joint compound. Make sure you estimate for the fasteners you plan to use, and rent any equipment and scaffolding that is needed to finish ceilings.

For ceilings and walls with 16" on-center framing use standard 1/2" drywall. For 24" on-center framing, use 5/8" drywall.

Types of Drywall

There are many types of drywall available at your local home center. From thicknesses that range from 1/4" to 5/8" to wall sizes that start at 4' x 8', there is a drywall product that is designed to suit your interior wall needs. If you are finishing a garage or another area where a fire rating is required, look for fire-resistant drywall. If you need to finish a wet wall, make sure you use a product that is able to handle more than average moisture content.

Regular
The most typical drywall used in standard interior applications is 1/2" drywall in 4' x 8' panels. It is also available in 1/4", 3/8", and 5/8" thicknesses (Image 1).

Standard Drywall is Most Typical for Regular Use

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Moisture-resistant
Sometimes called greenboard, due to its color, this has the same gypsum core as drywall, but with a water-resistant facing. It is typically used in wet areas such as around a bathtub. Not waterproof (Image 2).

Green Board Used in Areas with Moisture Levels

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Fire-resistant
This type of drywall has a core with additives that contain fires well. Fire rating for panels is measured in time. Due to its tougher core, it can be more difficult to cut (Image 3).

Fire Resistant Drywall Used in Areas of Concern

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Flexible
When you have an arch or a curved wall, 1/4" flexible drywall is the best type to choose. It has a stronger paper face than regular 1/4" drywall and is more resistant to cracking (Image 4).

Flexible Drywall Used for Curved Walls and Arches

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Cement board
Sometimes called concrete backerboard or the brand names of Durock and Wonder Board, it is used as a surface for ceramic tiles. It is not a gypsum-based product, as it has a solid concrete core (Image 5).

Cement Board Used in Showers or Saunas

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

Gp's Denshield
This is a mold-resistant board used for tiling. It has a glass face and an acrylic coating that prevents moisture from entering the wall cavity (Image 6).

GP Denshield is Excellent Backer for Tiling

Photo By: DK - Do It Yourself Home Improvement ©2009 Dorling Kindersley Limited

DK - Do It Yourself Home Improvement, 2009 Dorling Kindersley Limited

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