If you’ve ever wondered what is drywall and why nearly every wall in your home is made of it, the short answer is a panel of gypsum plaster sandwiched between two heavy paper faces. Also called gypsum board, wallboard, or by the brand name Sheetrock, drywall replaced the slow, labor-intensive plaster-and-lath construction of older homes with a fast, affordable, and consistent way to build interior walls and ceilings. It’s the unglamorous material behind almost every painted surface you see indoors.
This guide explains what drywall is made of, the different types and thicknesses, how it gets installed and finished, and what it costs, so you can talk to a contractor knowledgeably or tackle a repair yourself.
What Drywall Is Made Of
At its core, drywall is a panel of gypsum, a soft mineral of calcium sulfate, pressed into a flat sheet and wrapped in paper. The gypsum core is naturally fire-resistant because it contains chemically bound water that turns to steam when heated, slowing the spread of fire. That fire resistance is a big reason drywall became the standard for interior construction and is required by building codes in many applications.
The paper facing gives the panel strength and provides a smooth surface ready for finishing. The front paper is smooth for painting or texturing, while the back paper provides structural backing. Standard panels are gray or off-white, but the color of the paper often indicates the type, green for moisture resistance, purple for enhanced moisture and mold resistance, and other colors for specialty products. Understanding this simple gypsum-and-paper construction explains why drywall is easy to cut and install but also why it crumbles when it gets wet.
Standard Panel Sizes and Thicknesses
Drywall comes in standard sheet sizes, most commonly 4 feet wide by 8 feet long, which is manageable for one or two people to carry and hang. Longer sheets, 10 and 12 feet, are available to reduce the number of seams on large walls and ceilings, though they’re heavier and harder to handle. The 4-foot width is designed to span standard framing spaced 16 or 24 inches on center.
Thickness is the other key spec, and it varies by application:
- 1/4 inch: flexible, used for curved walls and skim-coating over existing surfaces
- 3/8 inch: for repairs and re-covering old walls
- 1/2 inch: the standard for interior walls in most homes
- 5/8 inch: thicker, stiffer, used for ceilings (resists sagging) and fire-rated assemblies
The 1/2-inch panel is what you’ll find on most walls, while 5/8-inch fire-rated board is common on ceilings, in garages, and between attached living spaces where code requires added fire protection.
Types of Drywall for Different Jobs
Not all drywall is the same, and choosing the right type for each location matters. Standard drywall handles the vast majority of interior walls and ceilings in dry rooms. Moisture-resistant drywall, often called green board for its green paper, resists humidity and suits bathrooms, laundry rooms, and kitchens, though it is not waterproof and should never sit behind tile in a shower without a separate waterproof membrane.
Mold-resistant drywall, typically purple, upgrades moisture and mold protection further and is worth the small premium in bathrooms and basements. Fire-resistant drywall, called Type X, uses a thicker 5/8-inch core with glass fibers to earn a one-hour fire rating, required in garages, near furnaces, and in shared walls. There’s also cement board, a distinct tile-backing product that goes behind tile in wet areas, and soundproofing drywall with a dense core that dampens noise between rooms. Match the type to the room’s conditions and code requirements.
How Drywall Gets Installed
Hanging drywall is a straightforward process that goes quickly with two people. Panels are cut to size by scoring the paper face with a utility knife, snapping the panel along the score, and cutting the back paper. The sheets are then fastened to the wood or metal studs and ceiling joists with drywall screws (or occasionally nails), driven so the head dimples just below the surface without breaking the paper.
Installers hang ceilings first, then walls, positioning panels to stagger the seams and minimize joints. Horizontal hanging on walls is common because it places the long seams at a convenient height and reduces the total seam length. Around outlets, windows, and fixtures, the drywall is measured and cut precisely so the panels fit snugly. Proper screw spacing, typically every 12 to 16 inches, keeps the panels tight against the framing and prevents future popping and cracking. Hanging is the fast part; finishing is where the real skill lies.
Taping, Mudding, and Finishing
Raw hung drywall is full of visible seams and screw dimples, and turning it into a smooth, paint-ready surface is the art of drywall finishing. The process uses joint compound, called mud, and paper or fiberglass tape. First, tape is embedded in a layer of compound over every seam, and screw dimples are filled. After that dries, additional coats of mud are applied progressively wider, feathering the compound out so the seam blends invisibly into the flat panel.
A typical finish takes three coats of mud, with sanding between coats and a final sanding to a smooth surface. Finishers rate the result in levels, from Level 0 (no finish) to Level 5 (a skim coat over the entire surface for the smoothest possible result under critical lighting). Most homes are finished to Level 4. This taping and mudding process is time-consuming and messy, and doing it well takes practice, which is why many DIYers hang their own drywall but hire a pro to finish it. Poor finishing shows through paint as visible seams and bumps.
Repairing Common Drywall Damage
Drywall’s biggest advantage for homeowners is how easily it repairs, and knowing the basic fixes saves hundreds in service calls. Small holes from nails or screws fill with lightweight spackle applied with a putty knife, sanded smooth once dry, and painted over, a five-minute job. Medium holes up to a few inches, from a doorknob or a foot, get patched with a self-adhesive mesh patch covered in two or three thin coats of joint compound, feathered out and sanded flush.
Larger holes require cutting out a clean rectangle, backing it with wood or a patch panel, and screwing in a new piece of drywall before taping and mudding the seams. Nail pops, where a fastener works loose and pushes the surface out in a small bump, are fixed by driving a new screw an inch away, resetting the popped fastener, and filling both dimples. Water damage is the exception that usually demands replacement rather than repair, since wet gypsum loses its strength and can harbor mold. Cut out the soft, stained section entirely, address the leak that caused it, and patch in fresh board once everything is dry.
Costs and When to Hire a Pro
Drywall is inexpensive as a material. A standard 4 by 8 foot half-inch panel costs roughly $12 to $20, and installed drywall, including hanging, taping, and finishing, runs about $2 to $4 per square foot of wall area. A single room might cost $500 to $1,500 to drywall completely, while a whole house runs several thousand dollars depending on size and finish level. The material is cheap; the labor and skill of finishing drive most of the cost.
DIYers can reasonably handle small repairs, patching a hole, replacing a water-damaged section, or hanging drywall in a garage or basement where a flawless finish isn’t critical. Larger projects and any highly visible walls benefit from a professional, because achieving smooth, invisible seams over an entire room is genuinely difficult and slow for a novice. Now that you know what drywall is, how it’s built, and how it’s finished, you can decide which parts of a project to take on yourself and where hiring an experienced hanger and finisher will save you frustration and deliver a wall that looks flawless under paint.
