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This page was last revised on August 19, 2001.
THE key to doing drywall is to get very, very good at putting on the "mud."
- The top ten reasons for getting really, really good at doing drywall:
- 10. To minimize sanding
- 9. To reduce need for cleanup
- 8. To minimize sanding
- 7. To reduce the amount of materials used
- 6. To minimize sanding
- 5. To reduce the time it takes to get the job done
- 4. To minimize sanding
- 3. To create better-looking results
- 2. To minimize sanding
- 1. To minimize sanding
Sanding drywall is one of the most miserable jobs possible in the construction industry--that
and putting up fiberglass batting.
- What is drywall? It's flat, formed sheets of gypsum bound in a paper cover. A rougher,
thicker paper covers the back and the two long edges, wrapping around these edges. The front is
covered by a thinner, smoother sheet of paper that overlaps the backing paper in the bevels. The
bevels are tapered surfaces along the long edges that make the long edges thinner than the bulk of
the drywall sheet. The ends of the sheet are uncovered.
- Drywall is commonly available in sheets four feet wide, and either eight, ten, or twelve feet
long. It is usually available in thicknesses of 3/8", 1/2", and 5/8". The 3/8" should NEVER be
used EXCEPT in cases where it's an additional layer over an existing wall. The 5/8" gives the best
results overall, and is the minimum thickness that is regarded as "fire-rated": that is, resistant
enough to fire to significantly increase safety. Drywall always comes in double sheets that are
bound together by paper tape covering the ends. Moving it as the double sheets minimizes the
possibility of damage to it.
- There are two ways to hang drywall: horizontally, or vertically. It was made to hang vertically,
but many people prefer to hang it horizontally, largely because each sheet bridges more joists that
way. For ceilings, it should ALWAYS be hung at right angles to the direction of the joists so that
it bridges the most joints.
- Whenever possible, make all joints within a wall bevel-to-bevel. Avoid butt joints, where the
sheets are end-to-end, or cut-to-cut. Hanging drywall vertically makes this easy. For almost every
wall, it will be necessary to have at least one cut edge to the drywall; this cut edge should whenever
possible be placed in the corner.
- Cutting drywall is usually easy. Materials recommended: 1) sharp utility knife with plenty of
replacement blades; 2) tape measure; 3) drywall square and/or chalk line. To cut it, measure the
drywall, and either use the chalk line to snap a line or use the drywall square to draw a line in
pencil. Do this on the front of the drywall. Then, with the drywall well-supported, use the utility
knife to score a shallow cut on the line. Go over this scored line another time or two with the
knife, then simply snap the drywall back, like it's hinged, and it will break fairly cleanly. With it
folded partially back, cut the paper on the back side, and it's cut. You may sometimes need to use
the utility knife to clean the edge of the cut.
- When hanging drywall around a door or window, try to place the corner of the door or
window into the sheet of the drywall. Don't patch together two pieces of drywall to form the
corner. Here, a drywall saw, which much resembles a keyhole saw, is really handy to make the
first cut, and then the second cut can easily be scored and snapped.
- Before hanging the drywall, measure where the supports (joists, studs, etc.) are, and mark
them on the drywall sheet with the chalk line. This will prevent misses with the drywall screws.
- Use drywall screws to hang the drywall. These are #6 Philips bugle-head screws, preferably
with coarse thread, and usually black (you're wasting money using the silver-colored decking
screws). Recommended length is 1 5/8". You should use a drill or power drywall driver to drive
these, with an appropriate Philips bit. I highly recommend using a drywall dimple bit, in which the
Philips driver bit is housed in a bell-like structure. This prevents overdriving the screws, which is a
frequent problem when hanging drywall. A screw that's properly driven should be embedded
within the surface of the drywall, so that all parts of the screw are below the surface of the sheet,
but without breaking the paper. For 5/8" drywall, screws should be placed every six inches on
every underlying support. For any other drywall, they should be at least every eight inches
(although some sources will say that every twelve inches is okay, but a ceiling sheet should
NEVER have screws twelve inches apart).
- There are three kinds of joints in hanging: corner, bevel, and butt. In each case, the joints
must be taped before being finished. Some people still use the old paper tape, which I strongly
discourage. Instead, use the self-adhesive fiberglass mesh. Unroll it like tape, centering it on the
joint, and cut it with the utility knife. Unlike paper tape, apply it BEFORE applying any drywall
mud. It will lie within the bevel and will never show if the job's done properly.
- When finishing a beveled joint, the dried compound, when sanded, should be exactly even
with the surface of the drywall sheet. This is why the joints are beveled.
- For finishing inside corners, buy and use an inside corner trowel. This is an indispensible tool.
When you first put on the mud, put it on somewhat loosely, and to spread it, hold the trowel rather
flat to the surface. Then go back over the joint with the trowel held at a greater angle to the wall
and use more pressure. Then use your flat trowel to scrape away the little ridges that have formed
at the edge of the path of the corner trowel.
- After finishing and sanding all the drywall, use a drywall primer in order to get the best results
from your final wall finish, whether it's paint or wallpaper.
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