Drywall 101

Drywall, wall board, sheetrock, gypsum board, plaster board, Gyproc or Gib. It’s a building material that comes in many forms and has many names, but they all share virtually the same design that’s been in effect since 1888. Without it, most houses in the US would be nothing more than framing. It’s Drywall and you either love it or you hate it. Read on for everything you’ve ever wanted to know about drywall, and more!

How Drywall is Made

Almost all drywall is made using a pressed gypsum sheet that is wrapped on both sides with paper, which is used both to support the fragile gypsum board and as a finished wall surface. On the interior side of the drywall, the paper is made from plain-brown waste stock paper. This is where shipping codes and tracking numbers are located. The exterior face of the drywall is covered with a finer piece of paper that is used as the finished surface of the wall. This paper accepts joint compound, mastic, thinset and paint exceptionally well.

How Drywall is Installed

Drywall is attached to the interior of the home using drywall screws—typically 1 ¼” black phosphate coated #6 screws. The screws are set 6-8” apart on the edge and 9-12 inches in the field for the wallboard. The ceiling boards should be attached 6-8” in the field and on the seams.

The ceiling board is installed first, followed by the upper wall boards. This creates a tight bond for the hardest to finish areas of a room: the ceiling to wall joint, not to mention gives you some really strong muscles thanks to the heavy lifting. The lower sheet is installed last, off of the ground. This keeps the drywall sheet off the slab and makes the seam tight where the two drywall boards meet.

Drywall screws are only supposed to indent the paper surface; not tear into it. Check your screw depth with a depth-sensitive screw gun like one of these from our sponsor Tyler Tool. These prevent the screw from tearing through the paper and will help keep your drywall nice and tight against the walls and ceilings.

Drywall Finish Levels

After the drywall has been attached, it can be finished (provided there is no drywall inspection) with joint compound, sealing the screw holes and drywall joints. Paper or fiberglass “tape” is applied to the seams with joint compound and a spackling knife. After each successive coat, it is allowed to dry. It’s then sanded and another coat of joint compound is added until the surface is smooth. Anywhere from 2-5 coats provide various grades of finish that are rated by a number system. It’s just like “Dante’s Inferno” – drywall levels are exactly like levels of hell, each one is much worse than the next (unless of course you don’t have to do the work).

• Level zero is the bottom of the barrel. It’s just drywall with no finish. No tape, no corner bead, no joint compound of any kind.
• Level One drywall finish is what you would see in an attic or crawlspace. It’s usually a single piece of drywall tape and joint compound covering the seams. This is typically done for fire resistance in crawlspaces and on fire walls in commercial or multi-use structures. No sanding is needed and often tool marks or ridges are found throughout the finished surface.
• Level two drywall finish is what you would see in an unfinished basement or warehouse. It has finished corners, covered screw holes and one solid coat over the joints. While some tool marks are acceptable, finishing is generally done neatly, although sparingly.
• Level three is typically two coats or less and is used only where a heavy drywall texture will be applied. Ceilings with a stomp texture and walls that are being covered with a commercial-grade wall covering primarily use this grade of drywall finish.
• Level four is a light duty residential grade finish. This 3-4 coat finish is used for a lightly textured wall, wallpaper or painted directly using flat or low sheen paint. Never use a semi-gloss or gloss paint as this can create what is known as joint photographing. No, that doesn’t refer to photo-ops at a Reggae concert; joint photographing is just fancy terminology for being able to see the joint compound through the paint.
• Level five is the highest level of drywall finish: it’s what you see in hospitals and libraries. It takes five or more coats of joint compound, a skim coat that covers the entire surface, and a highly skilled hand to get this level of finish. It’s ready to paint after a finish primer is applied.

If hearing about all the levels of drywall is getting you hot and bothered, be sure to check out our article on plaster vs drywall.

Drywall Textures

Drywall texturing is a messy, messy job. Imagine squirting liquid joint compound in a fine mist over your head for hours at a time. Needless to say, you’re going to look like a bird feeder on the set of the movie “The Birds” once you’re done working with the stuff.

Professional drywall texturing is done using compressed air, a graduated nozzle and large spray rig canister, typically all hauled on a trailer. Compressed air and the wet mixed joint compound is shot out of a handheld gun nozzle (imagine “Ghostbusters” guns) that atomizes the joint compound instantly, providing any texture needed. Super messy and requires lots of plastic and painters tape.

Handheld hopper rigs can be used to texture smaller areas of the house. These use a large hopper attached directly to the top of the gun and a compressed air hose attached to the bottom of the gun to atomize joint compound to a fine mist. A small dial in the front of the handle allows more air shoot out of the nozzle, allowing a finer or thicker texture to be achieved as needed. Rent or buy these rigs for small houses and room additions.

Even smaller textured drywall repairs can be made using small spray cans filled with joint compound. These work pretty good for most small applications like a door handle hole repair. Be sure to test spray a small piece of cardboard first. This will let you get the closest match to the existing texture as possible without allowing you to make a mistake on the final texture.

Did we miss any key points about drywall? If so, please share your thoughts in the comments below.