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As opposed to a week-long plaster application, an entire house can be
plasterboarded in one or two days by two experienced plasterboarders, and
plasterboard is easy enough to use that it can be installed by many amateur home
carpenters. In large-scale commercial construction, the work of installing and
finishing plasterboard is often split between the plasterboard mechanics, or
hangers, who install the wallboard, and the tapers and mudmen, or float crew,
who finish the joints and cover the nailheads with plasterboard compound.
plasterboard is cut to size, using a large T-square, by scoring the paper on the
front side (usually white) with a utility knife, breaking the sheet along the
cut, scoring the paper backing, and finally breaking the sheet in the opposite
direction. Small features such as holes for outlets and light switches are
usually cut using a keyhole saw or a small high-speed bit in a rotary tool.
plasterboard is then fixed to the wall structure with nails, or more commonly in
recent years, the now-ubiquitous plasterboard screws.
plasterboard fasteners, also referred to as plasterboard clips or stops, are
gaining popularity in both residential and commercial construction. plasterboard
fasteners are used for supporting interior plasterboard corners and replacing
the non-structural wood or metal blocking that traditionally was used to install
plasterboard. Their function serves to save on material and labor expenses; to
minimize call backs due to truss uplift; to increase energy efficiency; and to
make plumbing and electrical installation simpler. Many green building and
energy efficiency models suggest using plasterboard fasteners to conserve
resources and save energy, including the U.S. Dept. of Energy.
plasterboard screws are designed to be self-tapping.plasterboard screws have a
curved, bugle-shaped top, allowing them to self-pilot and install rapidly
without punching through the paper cover. These screws are set slightly into the
plasterboard. When plasterboard is hung on wood framing, screws having an acute
point and widely spaced threads are used. When plasterboard is hung on
light-gauge steel framing, screws having an acute point and finely spaced
threads are used. If the steel framing is heavier than 20-gauge, self-tapping
screws with finely spaced threads must be used. In some applications, the
plasterboard may be attached to the wall with adhesives.
Electric screw gun used to drive plasterboard screwsAfter the sheets are secured
to the wall studs or ceiling joists, the seams between plasterboard sheets are
concealed using joint tape and several layers of joint compound (sometimes
called "mud"). This compound is also applied to any screw holes or defects. The
compound is allowed to air dry then typically sanded smooth before painting.
Alternatively, for a better finish, the entire wall may be given a skim coat, a
thin layer (about 1 mm or 1/16 inch) of finishing compound, to minimize the
visual differences between the paper and mudded areas after painting.
Another similar skim coating is always done in a process called veneer
plastering, although it is done slightly thicker (about 2 mm or 1/8 inch).
Veneering uses a slightly different specialized setting compound ("finish
plaster") that contains gypsum and lime putty. For this application blueboard is
used which has special treated paper to accelerate the setting of the gypsum
plaster component. This setting has far less shrinkage than the air-dry
compounds normally used in plasterboard, so it only requires one coat. Blueboard
also has square edges rather than the tapered-edge plasterboard boards. The
tapered plasterboard boards are used to countersink the tape in taped jointing
whereas the tape in veneer plastering is buried beneath a level surface. One
coat veneer plaster over dry board is an intermediate style step between full
multi-coat "wet" plaster and the limited joint-treatment-only given "dry" wall.
Plasterboard - cutting and fixing Plasterboard types
Wallboard or plasterboard is a flat seam of gypsum, sandwiched between stiff
lining paper. It comes in several types and sizes and is ideal for timber framed
buildings, loft conversions, stud-partitions and ceilings. The most common size
is 2.4m by 1.2m and is grey surfaced, for plastering, or ivory faced, which can
be painted or decorated directly.
Ivory boards may have tapered edges so the joints can be flush filled. The
boards are available in thickness of 9.5mm or 12.7mm. Boards measuring 900mm x
1200mm and 1800mm x 1200mm are commonly stocked. Longer lengths can be ordered.
Plasterboard and wallboard is available with a vapour barrier, a thin metallic,
tinfoil-like backing. These are used in timber framed buildings and as a
sheathing where moisture could be present.
There are boards for other uses but these are specialised and have to be
ordered:
Duraline - Impact protection - Mustard colour surface
Soundbloc - Sound insulation - Blue colour surface
M.R Board - Moisture resistant - Silicone green liner
Fireline - Fire resistant - Pink colour surface
Measuring cutting and scribing plasterboard
To cut plasterboard to size ...
Measure the opening at the top and the bottom
Transfer the measurements to the face side of the plasterboard.
Hold a straight edge on the measurements marked
Using a trimming knife, run the blade down the edge of the straight edge,
cutting through the layer of lining paper and into the gypsum.
Stand the sheet on its edge and snap it at the cut.
Fold on the cut and run the knife up the fold from the other side, cutting the
backing paper.
To scribe plasterboard
This is when you have to fit a board into an uneven opening.
Measure the opening at its widest point.
Cut the plasterboard parallel at this width.
Hold the cut edge of the board, plumb and inline with the opening at its
narrowest point.
Using a small block of wood the same width as the widest point of the opening as
a gauge, scribe a pencil line down the board parallel to the wall.
Cut on this line. Fit the board up against the opening. If needed, trim any
proud bits by using the edge of an old saw as a file. In some cases you may have
to use a saw, or in extreme cases a pad saw, when the line of the cut is not
straight enough to use a trimming knife.
When using a trimming knife, wear work gloves, and, as always when cutting, cut
away from the body.
Fixing boards to Studwork
When nailing plasterboard, use purpose made plasterboard nails - these are
galvanised or zinc coated, round head nails. They will not rust and spoil the
décor at a later date. Always give them that last tap, to ensure they dimple the
surface of the plasterboard. This is to prevent them catching the edge of the
float and to allow plaster coverage.
You can also use plasterboard or plasterboard screws. Although moderately more
expensive, they tend to hold the board more firmly. This is particularly helpful
when boarding both sides of a stud wall, where hammering the second side might
loosen the nails on the first side.
General sizes are 30mm for 9.5mm boards and 40mm for 12.7mm boards. Nail at
approx 150mm centres. As usual, check that no pipes, cables or other services
run behing the proposed fixing points.
In order to lift plasterboards firmly against a ceiling make a foot lever. Nail
a piece of 50mm x 25mm to a 20mm dowel so that the dowel forms a fulcrum for the
flat piece to rock on.
When the sheet is in place, tilt it up and push one end of the lever under the
bottom edge. Press down firmly on the other end with your foot and the sheet
will lift tight up to the ceiling. Nail in position.
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