|
Drywall - Application
1.
Drywall can be
installed either vertically or horizontally. Plan your installation so
that the least number of seams are created. Use this criteria to choose
the size of drywall for your project and plan the application before
proceeding. Remember that when two boards butt up against each other at
their long edges, both must have a beveled factory edge.
2.
Use a scraping
plane or rasp on cut edges to smooth any roughness.
3.
When
positioning the drywall panel, align the top of each panel with the
ceiling edge or the angle break to assure a clean edge. To raise the
panels you can make a foot fulcrum with two pieces of wood.) Any gaps
should fall close to the floor where a baseboard will cover them. All
joints between boards should be positioned to meet over the center of a
stud or rafter.
4.
Start a couple of
drywall nails at the corners and across the top of the drywall
panel before you lift it into place. Once the panel is positioned, it will
be easier to attach while another person holds it in place.
5.
The best
drywall nails have cupped heads which make them easier to cover when
mudding and taping. Those with barbed shanks increase holding power and
reduce "nail popping". Nail along the edge of the panel about every six
inches, hammering the nail into the stud. In the middle of the panel, nail
about every twelve inches. Check local code for variance. It is
advisable, if the studs are new wood, to double nail in the field.
6.
Hammer each nail until
it is forced slightly below the surface of the panel - this is called
dimpling. Also be careful not to ding the edge of the panel when nailing
or handling. Dings require extra mudding and finishing work. If you are
using drywall screws, be sure you screw them to just below the surface of
the panel. But do not break the paper when you do this. If the paper is
broken, drive another nail nearby to assure a good hold. It is advisable
to have a special drywall hammer or a cordless
electric drywall screw gun for speed and ease of handling.
7.
Place nails in
adjoining sheets directly across from each other where they meet at a
stud. This makes mudding easier. ff you miss the stud, pull out the nail
or screw and dimple the hole so as to be able to mud and tape over it
properly.
8.
Another alternative is
to glue the drywall with drywall adhesive . The glue is used
in the center of the board with nails used around the edges. Follow the
manufacturer's instructions when gluing. The glue avoids seams that need
to be taped and finished.
9.
As you apply the
drywall try not to leave a gap between boards more than 1/8 to 1/4 of an
inch - less if possible.
10.
If
required, get your nailing pattern inspected (check local code *) before
covering with tape and spackling.
------------------------------------------------------------------------------------------------------------------------------------------------
Cutting Drywall for Openings
1.
Applying drywall around
openings like doors and windows, calls for extra care and accurate
cutting. Never try to fit around a large opening with just one panel. Work
with two pieces about the same size, with a seam that meets in the middle
over the opening.
2.
Seams must always meet
at a stud but should never occur at the edge of a door or window. The door
opens and closes at this point and the seam will eventually crack from the
movement. Be particularly careful not to damage the board when cutting a
notch or corner.
3.
For right angle
openings, use a drywall T-square or a chalk line
to mark the board for cutting. Cut the shorter length with a wallboard
saw or keyhole saw. Then use a utility knife to score the longer cut. Use
several fight strokes with the knife to cut into the core. Position the
cut over the edge of your work table and snap the panel. Finish by cleanly
undercutting the paper on the back side with the utility knife. Always cut
with the good side up.
4.
To cut an opening
around a window, place the panel in position and mark on the edge of the
panel to indicate the top and bottom of the window opening. Measure and
record the distance from the top mark to the edge of the window and from
the bottom mark to the edge of the window. Use a drywall square to connect
the points and make your cut accordingly.
5.
For smaller openings
Eke outlets, an efficient trick is to outline the opening with lipstick or
colored chalk. Then fit the panel into place and give it a couple of good
whacks over the outlet area. The lipstick will transfer to the back of the
panel for a cutting pattern.
6.
Cut this patch out with
your keyhole saw. Take care when cutting from the back side of the panel
not to tear the paper beyond the patch hole area. Use the utility knife to
finish cutting through the paper on the front side of the panel.
-------------------------------------------------------------------------------------------------------------------------------------------------
Drywall Installation, No Mistakes Allowed
By: Paul Bianchina
There is probably no material more noticeable
and more commonplace in today’s home than drywall. Comprised of a core of
compressed gypsum covered on both sides with a layer of tough paper,
drywall – also commonly known by the popular trade name Sheetrock – is the
overwhelming choice of builders and remodelers for covering interior walls
and ceilings.
There is a surprisingly wide variety of sizes,
thicknesses, edge treatments, core additives, and paper coatings available
in drywall, depending on the installation method and the intended
application. Thicknesses range from 1/4" and 3/8", which are used over
solid backing in remodeling situations to cover problem areas such as bad
plaster, to the much more common 1/2" and 5/8" thicknesses, which can be
used to span studs and joists up to 24 inches apart. Sheet sizes of 4 x 8
feet – which have the advantage of being easier to handle -- and 4 x 12
feet – which require less seams -- are both commonly available.
Cutting the Sheets
Typically, installation begins with ceiling. A
small gap is left between the edges of the drywall and the spot where the
ceiling framing meets the wall framing, and by installing the ceilings
first, you can then cover that gap with the sheets you install on the
walls. The sheets are installed so that the long dimension of the sheet
runs perpendicular to the direction of the ceiling joists.
Start in one corner with a full sheet. Measure
from the corner to the center of the joist that is closest to but
less than eight feet from the corner (or 12 feet if you’re using 12-foot
sheets). Cut the sheet to length, and you’re ready to go.
To cut drywall, use a straightedge and a
utility knife. Working from the face of the sheet, place the straightedge
along the line where you want to make the cut – four-foot long aluminum or
plastic T-squares are available inexpensively wherever you buy your
drywall, and greatly simplify the cutting process – and use the
straightedge as a guide for your knife. You don’t need to cut all the way
through the drywall – just cut deep enough to get through the layer of
paper and slightly into the gypsum.
With a quick downward motion, snap the drywall
along the cut line. This will break the gypsum core, and leave on the
backing paper still intact, like a hinge. Use your knife to cut the
backing paper, and separate the cut piece from the rest of the sheet. To
clean up the rough edge, sand it lightly with a Stanley Surform plane –
available inexpensively at any home center or hardware store – or scrape
it with the edge of your knife or a block of wood.
To cut out around electrical boxes and other
obstructions, a drywall saw is used. This is a short, coarse-toothed blade
with a point on one end and a wood or plastic handle on the other – again
available wherever you buy your drywall supplies. After laying out the
location of the cut, place the point of the saw against the face of the
drywall and tap it until it punctures the sheet, then saw out the waste
material.
------------------------------------------------------------------------------------------------------------------------------------------------
Installation
Drywall is actually a very easy material to
install, other than its weight. Half-inch drywall weighs in at almost 2.5
pounds per square foot, or close to 80 pounds per sheet, so hanging it
should always be a two-person job. The sheets are big, awkward and
flexible – especially in the 12-foot lengths – making them very unwieldy
for one person to handle alone.
After cutting the sheet to size, set up two
ladders or benches. Working together, lift the sheet – backside up – and
push it firmly into contact against the underside of the joists. Check the
alignment carefully, especially on the first sheet, and make sure the end
is centered on the joist. If you miss your layout here, you’ll have
problems with each of the following sheets.
Fasten the sheet in place using drywall nails –
which have a rust-resistant coating and a cupped head to hold the drywall
mud later on – or drywall screws. The nails are installed with any type of
hammer that has a convex head, and are driven in just deep enough to dent
the face paper of the drywall sheet – called a dimple – but not deep
enough to go through it. Screws can be installed with an electric or
cordless screw gun, and here again you want the screw head to end up just
below the surface of the paper but not puncture through it.
Drywall supplies and tools are available
through just about any home center, lumberyard, hardware store, discount
center, and other retailers where building supplies are sold. You can
arrange for deliver of the drywall as well, but expect to pay a small fee
per sheet. Rental yards have many of the drywall installation and
finishing tools you’ll need, and you can also rent a drywall jack to lift
and position the sheets and hold them in place while you fasten them – a
real plus when hanging a ceiling.
Copyright 2002 Inman News Features. Distributed by Inman
News Features
-------------------------------------------------------------------------------------------------------------------------------------------------
Drywall Texture is a Matter of Taste and Technique
By: Paul Bianchina
A good drywall job can create a smooth and uniform series of walls
and ceilings throughout any home. But it’s the application of texture in
all of its varied forms and designs that goes a long way toward creating
the home’s individual look and feel.
Drywall texture can take a wide variety of
forms and what appeals to different people is often a matter of the
materials used, the techniques employed and individual taste. From a
light, machine-applied “orangepeel” to the heavy swirls of a hand-applied
Mediterranean look, there’s something for everyone.
Getting Ready
Texture is the last thing applied to the drywall after the
completion of the installation and topping processes. The drywall is
completely hung and taped, then all of the seams are covered and smoothed
over with successive coats of drywall cement until the walls appear
seamless. Once the topping is done, most drywallers prefer to prime the
drywall prior to applying the texture.
The primer coat seals the porous paper surface of the
drywall and helps to point up any flaws in the finish topping coats prior
to putting on the texture. Priming can be done with wallboard sealer or
with a primer – talk with your paint store or drywall supplier for their
specific recommendations.
Following the application of the sealer, you’ll next want
to mask off any areas that aren’t going to be textured – areas where you
wish to preserve a totally smooth surface for paint or wallpaper – as well
as any areas that will be textured differently from the surrounding
surfaces.
Machine Applications
Because of its uniformity and greatly increased speed, most
texturing today is done by machine. Powdered texture material is mixed
with water, then air pressure is used to blow the texture through a
nozzle. For large areas, a professional texturing rig will give the most
uniform appearance. These are large, gas-powered, trailer-mounted machines
with an on-board mixer and a hundred feet or more of air and material
hoses, terminating in a trigger-operated texture gun with a variety of
interchangeable tips.
Smaller areas – typically no more than a room or two—can be
textured effectively by the do-it-yourselfer using a hopper gun, which is
simply a large plastic hopper mounted on top of a metal spray gun. Liquid
texture material is poured into the hopper, the gun is attached to an air
compressor, and the texture is sprayed onto the surface. Hopper guns are
more difficult to regulate and keep uniform, and since you’re carrying a
hopper full of material with you as you texture they are also very tiring
to use for long periods.
Hopper guns can be purchased inexpensively at most drywall
stores and home centers, or they can be rented. Variations in the
thickness of the texture material, the amount of air pressure and the size
of the opening in the nozzle – along with the speed and motion of the
person wielding the texture gun – dictate the final look of the texture.
The two most common machine-applied textures are:
1.
Orangepeel, also
called splatter, is the lightest texture. A combination of thin material,
high air pressure, a small nozzle opening, and a rapid spraying motion
creates small dots of texture on the wall.
2.
Knockdown, which
combines thicker material, lower air pressure, a larger nozzle and a
slower application to spray large globs of texture onto the surface. As
the texture begins to dry, a wide metal trowel called a knockdown blade is
pulled lightly over the texture globs, knocking down the high spots and
creating large flat areas. By varying the ratios of these four elements,
along with the pressure used during the knocking down process, knockdown
texture can be varied from very light to very heavy.
Physical Properties of Dependable PCMs:
There
are several important considerations necessary for combining PCM into
drywall. First, the transition temperature, or melting temperature, of the
PCM must be near standard or suggested room temperatures (for example,
65-72 ° F [18.3-22.2 ° C] for heating-dominated climates or 72-79 ° F
[22.2-26.1 ° C] for cooling-dominated climates).Because the PCM uses the
exchange of heat energy from its environment to drive the phase change,
this change of state from solid to liquid, or liquid to solid,
characteristically occurs within a temperature range of only a few
degrees.
Second, the PCM product must be effective, offering good heat transfer.
Otherwise, it is no better than common gypsum drywall. If manufacturers
can mass produce a low-cost, competitive PCM product, PCM-drywall for
instance, it will be the result of available, inexpensive PCMs and the
cost-controlling manufacture of the product.
Salt Hydrates, Paraffins, and Fatty Acids:
The three principal PCMs investigated for use in phase change drywall are
salt hydrates, paraffins, and fatty acids. Other PCM applications commonly
use salt hydrates. Since they absorb moisture, which decreases their
effectiveness, salt hydrates require costly and impractical encapsulation,
with a semi-impermeable coating for improved performance. Paraffins are
waxes.
They
are readily available, inexpensive, and melt at different temperatures
relating to their carbon-chain length. Paraffin can be incorporated into
drywall in two ways, by direct immersion and by adding permeated plastic
pellets to the drywall mixture during the manufacturing process. Since
drywall is a porous material, it can absorb melted paraffin when immersed
in it. Extra paraffin runs off, leaving no buildup of wax. Immersion times
vary depending on the amount of PCM uptake desired, however, they rarely
exceed ten minutes. PCM content ranges up to 30% of the composite weight
of 1/2 inch drywall.
Drywall dipped in paraffin becomes water resistant. While common gypsum
drywall is fire-resistant, PCM-drywall is quite flammable unless treated
with fire-retardant chemicals. Immersion is the simplest, lowest cost
method for making PCM drywall. To produce large quantities of PCM-immersed
drywall, manufacturers would need to make major modifications to equipment
and processes. This process is not recommended for do-it-yourselfers.
Polyethylene pellets, saturated with melted paraffin, then mixed with wet
gypsum and compressed in sheet form, also yield production quality
drywall.Relative to immersed drywall, this material is more
fire-resistant, less water-resistant, and conforms to the current gypsum
drywall manufacturing process. Both versions work well for heat transfer
and storage, and the paraffin remains permanently in the drywall.
The third type of PCM under study, fatty acids, come from meat by-products
and vegetables. They are cheap, renewable, and readily available. Like
paraffins, different types of fatty acids have different melting points.
To tailor the drywall for specific climates, the manufacturer varies the
PCM mixing ratio. Fatty acids are also incorporated into the drywall by
immersion or encapsulation. They yield similar heat and stability
characteristics as paraffin-based PCM wallboard.
Advantages and Disadvantages of PCM Drywall:
PCM drywall has several advantages over conventional
thermal mass in solar heating applications. Because the exposed surface is
so large and the PCM absorbs heat over a narrow temperature range, the
drywall need not receive direct sunlight. PCM drywall has a much greater
heat storage capacity than conventional thermal mass, and provides
excellent heat transfer. It demands no extra structural support and any
added installation cost is minimal.
PCM drywall also has some disadvantages. The correct
transition temperature for one climatic region will not be appropriate for
another. Getting the right temperature becomes doubly difficult in regions
that require both heating and cooling. Drywall manufacturers are reluctant
to complicate their manufacturing processes to take these regional
variations into account. On-site dipping of the drywall may suffer from
poor quality control.
Other considerations include deposits of surface volatile
impurities ("blooming"), fire retardancy, metal corrosion, odor, and
traditional application issues, such as the ability of paint to adhere.
There is great potential for phase change drywall. There are significant
issues and techniques to address, however, before it is ready for wide
market acceptance. PCM drywall is strictly a manufactured product;
do-it-yourself applications of phase change materials are strongly
discouraged.
Content Provided By the DOE
|
