Drywall

The stuff is known by many names:  gyproc, gypsum board, sheetrock, drywall, and simply wallboard.  I have also called it a few other more colourful names that cannot be repeated here.  One thing is certain:  at some point, most of us will end up working with this building material.  

 

Types

Drywall consists of a gypsum core with a coarse paper backing and smooth paper face.  Standard thickness is 1/2 inch but it is also available in 5/8 inch. 

Standard:  Can range in length from 8 feet to 12 feet.  Eight foot sheets are much easier to handle, but using longer sheets will reduce the number of butt joints.  5/8 inch sheets are recommended for ceilings as they have less tendency to sag.  However, they are considerably heavier than 1/2 sheets.

Fire Code:  This product is 5/8" thick and is usually required in furnace rooms and garages where the wall or ceiling are shared with the house.  Check with your building department.  

Blue Board:  This product uses moisture-resistant paper which is suitable for skim coating with plaster.  It is not designed for prolonged exposure to moisture, however.  It can been used as a backer for tile, but is not recommended for high humidity locations such as bathrooms. Cement board is the best choice as a backer for tiles in wet areas.

Green Board:  Both the core and paper are water-resistant.  This product is typically used in bathrooms as it can withstand the high humidity.  However, while water-resistant, it is not waterproof and should not be used in a location where it would come in direct contact with water. Again, cement board is the best choice for wet locations.

Supplies

Tape:  Paper tape is the choice of professionals.  Mesh tape is easier for the do-it-yourselfer as it is self-sticking.

Corners:  For outside and inside corners, look for the ones with the paper attached.  These do not need to be screwed or nailed. There are also plastic beads available for odd angles, as well as flexible beads for curved corners such as arches.

Screws:  Fine screws are used for metal framing, coarse screws are used for wood.  Use longer screws for thicker drywall, or for ceilings for greater holding strength.

Tools

Drywall Knives are used for applying compound.  Start with the narrowest knife (6") for the taping coat and work up to the widest knife (12") for the finish coat.  You may also find specialized drywall tools for applying compound to the inside and outside corners.  I found that the inside corner tool was very useful, while the outside tool was somewhat unnecessary.  

Sanding screens used for drywall are basically stiff mesh.  I recommend using a vacuum attachment to help control the dust.

Sharp utility knife is essential for cutting the drywall.  A keyhole saw is useful for quickly cutting out for junction boxes., although this too can be done with a utility knife. A power zip saw such as the Roto-Zip effectively replaces the hand tools, but will result in more dust. However, there is no better tool for cutting circles in drywall.

A small rasp can be used to create bevelled edges where the ends of two sheets butt together.

Drywall Gun OR Drywall Clutch Bit:  Drywall guns are designed to install the screws without breaking the face paper.  The same result can be achieved by using a drywall clutch bit on a standard drill.  The bit has a clutch mechanism that stops the bit rotation once the screw is just below the surface of the drywall.  Another type of bit, available at Lee Valley (item # 19J13.01), is a simple collar that disengages the bit from the screw once the screw is just below the surface.

General Tips

There are plenty of resources available that will provide better instruction than I can.  Be prepared to be confused as there is also a lot of conflicting information out there.  Here a few pointers to keep in mind:

1. Drywall should be hung perpendicular to the framing.  In other words, for vertical studs, drywall should be hung horizontally. This way, there is no need to attach screws through the beveled factory edges, and there will be fewer butt joints when longer sheets are used.  Screwing into the studs is also considerably easier as the screws are installed across the width of the sheet (4 feet) rather than along the length. In my first basement project, I hung the drywall vertically to completely avoid any butt joints at all.

2.  Drywall screws are typically spaced one foot apart.

3.  Leave a space between the bottom of the drywall and a concrete floor, to avoid moisture from wicking up into the drywall.

4.  Hang the drywall for the ceiling first. The wall sheets will help support the edges of the ceiling and prevent future sagging.

5.  When using metal framing, install a wood strip to provide a nailing surface wherever you plan to attach trim.  That way you can use finishing nails and have smaller holes to fill than if you used trim screws.  The nailing strip should be as  thick as the drywall and about a half inch less in width than the trim you plan on using.  Simply butt the drywall up against this strip.  (Thanks Aaron)

6.  Typical application of compound is in 3 coats:  First coat is the taping coat.  Only use enough compound to embed the tape and fill the screw holes.   Second coat is the fill coat.  The final coat is the finish coat.  Allow each coat to dry at least 24 hours, unless you are using quick dry compound. Pros will add a bit of dish soap to the compound to help reduce or eliminate air bubbles.

7.  When sanding, use long smooth strokes.  Don't over-sand.  I found myself doing a fourth coat because I sanded the third coat too much.

8.  To get rid of sanding marks for a smooth finish, go over the joints with a damp sponge.  Don't rub too hard, though. 

9.  Vacuum the surface of the drywall so that it is clean and dust-free.  

10.  Use a primer high in "solids" content.  Typically, two primer coats are applied followed by two top coats.  Use tinted primer to eliminate the need for a second top coat.

From the basement project in the bungalow: Left: We hung the drywall vertically to avoid butt joints (the ceiling was less than 8 feet. Middle: A piece of OSB nailed to a 2x4 became a "third hand" that provided additional support while we screwed the sheet in place for the ceiling. Right: The drywall with a couple of coats of mud.