This document provides information on gypsum board (drywall), including: 1. Gypsum is a mineral used to make gypsum board, which consists of a gypsum core bonded between paper facings. 2. Gypsum board has several advantages such as ease of installation, fire resistance, sound isolation, durability and economy. 3. There are different types of gypsum board for various applications, like regular board for walls/ceilings, fire-resistant Type X board, and moisture-resistant board for tiling.

1. Using Gypsum Board for Walls and Ceilings
WHAT IS GYPSUM ?
Gypsum is a mineral found in sedimentary rock formations in a crystalline form known as
calcium sulfate dihydrate CaSO4•2H2O.
The manufacturer receives quarried gypsum, and crushes the large pieces before any further
processing takes place. Crushed rock is then ground into a fine powder and heated to about 350
degrees F. It is then used as the base for gypsum plaster, gypsum board and other gypsum
products.
Synthetic gypsum, commonly known as the FGD (Flue Gas Desulphurization) gypsum or DSG
(desulphurised) gypsum may also be used in the production of gypsum board. This product is
primarily derived from coal-fired electrical utilities which have systems in place to remove sulfur
dioxide from flue gasses. The synthetic gypsum is then transported to the gypsum board
manufacturer; the production process for calcining synthetic gypsum is largely the same as with
mined gypsum only no primary crushing is necessary.
To produce gypsum board, the calcined gypsum is mixed with water and additives to form a
slurry which is fed between continuous layers of paper on a board machine. As the board moves
down a conveyer line, the calcium sulfate recrystallizes or rehydrates, chemically combining
with the water that was removed during calcination and reverts to its original rock state. The
paper becomes chemically and mechanically bonded to the core. The board is then cut to length
and conveyed through dryers to remove any free moisture.
WHAT IS GYPSUM BOARD?
Gypsum board is the generic name for a family of panel products that consist of a
noncombustible core, composed primarily of gypsum, and a paper surfacing on the face, back
and long edges. Gypsum board is one of several building materials covered by the umbrella term
“gypsum panel products.” All gypsum panel products contain gypsum cores; however, they can
be faced with a variety of different materials, including paper and fiberglass mats.
Gypsum board is often called drywall, wallboard, or plasterboard. It differs from other panel-
type building products, such as plywood, hardboard, and fiberboard, because of its
noncombustible core and paper facers. When joints and fastener heads are covered with a joint
compound system, gypsum wall board creates a continuous surface suitable for most types of
interior decoration.

2. Fig. 1 – Horizontally Applied Gypsum Wallboard Showing Joints and Framing
ADVANTAGES OF GYPSUM BOARD CONSTRUCTION
Gypsum board walls and ceilings have a number of outstanding advantages:
 Ease of installation
 Fire resistance
 Sound isolation
 Durability
 Economy
 Versatility
1 . Ease of installation
Gypsum board building systems are easy to install for several reasons. Gypsum board panels are
relatively large compared to other materials. They come in 48- and 54-inch wide sheets and in
lengths of 8, 10, or 12 feet, so they quickly cover large wall and ceiling areas. Gypsum board
assemblies require only a few tools for their construction. Gypsum board can be cut with either a
utility knife or a variety of saws, and it can be attached with a variety of fasteners, including
screws, nails, and staples. It can also be adhesively attached to many substrates. Gypsum board is
a lightweight material. Two workers can easily handle most panels and cover large areas in very
short time periods. Gypsum board is easily finished using either a few hand tools or relatively
modest machines. Gypsum board installers can quickly learn most application techniques in a
few hours.

3. 2. Fire resistance
Gypsum board is an excellent fire-resistive building material
3. Sound isolation
Preventing the transfer of unwanted sound to adjoining areas is a key consideration when
designing a building, specifically when taking into account the intended activities of the
occupants in the various parts of the building. Gypsum board wall and ceilings systems
effectively help control sound transmission.
4. Durability
Gypsum board is used to construct strong, high quality walls and ceilings that offer excellent
dimensional stability and durability. Surfaces created using gypsum board are easily decorated
and refinished.
5. Economy
Gypsum board is readily available and easy to apply. It is an inexpensive wall surfacing material
that provides a fire resistant interior finish. Gypsum board building systems can generally be
installed at significantly lower labor costs than most alternate systems.
6. Versatility
Gypsum board satisfies a wide range of architectural requirements for design. Ease of
application, performance, ease of repair, availability, and its adaptability to all forms of
decoration combine to make gypsum board unmatched by any other surfacing product.

4. TYPES OF GYPSUM BOARD
Using ever-developing new technologies, gypsum producers offer a variety of gypsum board
products for many specific applications, including: the surface layer of interior walls and
ceilings; a base for ceramic, plastic and metal tile; exterior sheathing and soffits; elevator and
other shaft enclosures; area separation fire walls between occupancies; and the fire-resistant layer
over structural elements.
Regular and Type X gypsum board (described below) are available in SEVERAL
THICKNESSES. Different thicknesses are typically used in the specific following applications:
 ¼ -inch – A low cost gypsum board used as a base in a multilayer application for
improving sound control, used to cover existing walls and ceilings in remodeling and for
curved surfaces.
 5/16 -inch – A specialty product primarily used in the production of manufactured
housing and in laminated double thickness for special sound control panels.
 3/8-inch – A gypsum board principally applied in a double-layer system over wood
framing and as a face layer in repair or remodeling.
 ½-inch – Generally used as a single layer wall and ceiling material in residential work
and in double-layer systems for greater sound and fire ratings.
 5/8-inch – Used in quality single-layer and double-layer wall systems. The greater
thickness provides additional fire resistance, higher rigidity, and better impact resistance.
 ¾-inch & 1 inch – Used in interior partitions, shaft walls, stairwells, chaseways, area
separation firewalls and corridor ceilings. Special edged panels are used in some interior
partitions.
Standard size gypsum boards are 48 inches wide and 8, 10, 12 or 14 feet long. The 48 inch width
is compatible with standard framing methods in which studs or joists are spaced 16 inches and 24
inches o.c. (Other lengths and widths of gypsum board are available from the manufacturer on
special order.)
Edges available are rounded, tapered, beveled, square edge, and tongue and groove (V-edge).

5. Common Types of Gypsum Board in Alphabetical Order:
 Abuse-resistant gypsum panels offer greater resistance to surface indentation, abrasion
and penetration than standard gypsum panels.
 Eased edge gypsum board, which has a tapered and slightly rounded or beveled factory
edge. It may be used as an aid in custom finishing of joints.
 Exterior gypsum soffit board is board designed for use on the undersides of eaves,
canopies, carports, and other commercial and residential exterior applications with
indirect exposure to the weather. Soffit board is available in 1/2 or 5/8 -inch thicknesses
with both regular and Type X core.
 Foil-backed gypsum board has aluminum foil laminated to the back surface of regular
gypsum board or other gypsum panel products. Foil-backed panels serve as vapor
barriers.
 Gypsum base for veneer plaster serves as a base for thin coats of hard, high strength
gypsum veneer plaster.
 Gypsum liner board serves as a liner panel in shaft walls, stairwells, chase ways, area
separation fire walls, and corridor ceilings. It has a special fire-resistant core encased in
moisture-resistant paper. Liner board is available in ¾ or 1 -inch thicknesses, widths of
24 or 48 inches and with square edges (sometimes eased square edges). Gypsum liner
board is also available with fiberglass mat facing that increases its weather and mold
resistance.
 Gypsum sheathing is used as a protective fire resistive membrane under exterior wall
surfacing materials such as wood siding, masonry veneer, stucco and shingles. It also
provides protection against the passage of water and wind and adds structural rigidity to
the framing system. The noncombustible core is surfaced with water repellent paper; in
addition, it may also have a water resistant core. Available in 2 feet and 4 feet widths, ½ -
inch and 5/8 -inch thick. It is also available with Type X core. Gypsum sheathing is also
available with a glass mat facing. This product is more weather resistant and mold
resistant than paper-faced gypsum sheathing, and it is often used as a substrate for
Exterior Insulating Finishing Systems (EIFS).
 Impact-resistant gypsum panels offer greater resistance to the impact of solid objects
from high traffic and vandalism than standard gypsum panels.
 Mold-resistant board incorporates various methods of preventing the growth of mold
and mildew on the board’s surface.
 Non-paper-faced gypsum board is unfaced or has a facing other than paper.
 Regular gypsum board (gypsum wallboard) is used as a surface layer on walls and
ceilings.
 Sag-resistant board is a ceiling panel that offers greater resistance to sagging than
regular gypsum products used for ceilings where framing is typically spaced 24 inches
o.c.
 Type C or Proprietary Type-X gypsum board is available in ½ -inch and 5/8 -inch
thicknesses and is required in some fire rated assemblies. Additional additives give this
product improved fire resistive properties.
 Type X gypsum board is available in ½ -inch and 5/8 -inch thicknesses and has an
improved fire resistance made possible through the use of special core additives. It is also

6. available with a predecorated finish. Type X gypsum board is used in most fire rated
assemblies.
 Water-resistant gypsum board has a water resistant gypsum core and a water repellent
paper. It serves as a base for ceramic or plastic wall tile or plastic finish panels in non-wet
areas. This product is available with a regular or Type X core and in ½ -inch and 5/8 -
inch thicknesses.
POINTS TO REMEMBER : Do not use water-resistant gypsum board on ceilings or soffits
unless extra framing is installed; do not exceed 12 inches o.c. between framing members. Do not
use water-resistant gypsum board as a tile-backing substrate material where the final surface is
directly exposed to running water; select one of several specialty products, including glass-mat-
faced gypsum board or cement-based board, as a tile-backing substrate for areas directly exposed
to running water.
Limitations of Use
For installation of gypsum board and finishes, maintain room temperature at not less than 40
degrees F for the mechanical application of gypsum board and not less than 50 degrees for the
adhesive application of gypsum board and for joint treatment, texturing and decoration, unless
recommended otherwise by the manufacturer. CAUTION: When using a temporary heat source,
do not allow ambient temperatures to exceed 95 degrees F in any given room or area. Maintain
adequate ventilation in the working area during installation and curing period. Do not use
gypsum board where exposure to moisture is extreme or continuous. Take care to ensure that the
gypsum board will not be exposed to temperatures exceeding 125 degrees F for extended periods
of time, for example, when located adjacent to wood burning stoves, electric lighting, electric
heating appliances or other heating units, or hot air flues.
APPLICATION OF GYPSUM BOARD
Gypsum board can be applied over wood or metal framing or furring. It can be applied to
masonry and concrete surfaces, either directly or to wood or metal furring strips. When applying
board directly to masonry or concrete surfaces, smooth or fill in any irregularities to ensure
proper attachment and an acceptable final finished surface. Furring properly attached to interior
sides of exterior walls provides flat surfaces for standard fastener application as well and
sufficient separation from substrates to overcome dampness in exterior walls. Do not allow
gypsum board to directly contact surfaces, such as concrete or soil, with potentially high
moisture contents. Most common in residential construction is the gypsum wallboard system1in
which the joints between the panels and internal corners are reinforced with tape and covered
with joint compound to create a surface suitable for final decoration. External corners are
normally reinforced with either a metal or plastic corner bead which in turn is covered with joint
compound. Exposed edges are covered with metal or plastic trim. The result is a smooth,
unbroken surface ready for final decoration of paint, textures, wallpaper tile, paneling, or other
materials.

7. STORAGE AND HANDLING
Schedule the delivery of gypsum board to coincide with its installation.
Store boards or panels flat and protected from the elements. Be sure that materials used as
storage supports (risers) are at least 4 inches in width and of uniform depth or length. As the
units of gypsum board are tiered, align risers carefully from bottom to top so that the load of
each tier is transferred directly to the next level of risers, thus avoiding sagging or otherwise
distorting the plane of the boards.
Avoid stacking longer boards on shorter boards to prevent the longer boards from warping or
breaking. Avoid leaning boards horizontally against vertical framing as they may shift and fall
and in turn injure workers. Also avoid leaning boards during periods of high humidity or else the

8. boards may warp. Remove shipping bags immediately after delivery to prevent the buildup of
condensation. Keep materials protected from the weather until ready for use on the jobsite. Take
care while moving boards not to drag them and damage their edges and corners.
Fig. 5 – Stud
Shrinkage with Reduction in Moisture Content
If framing shrinkage is substantial or nails are longer than necessary, the gypsum board may
separate from its framing lumber, which often causes nail heads to protrude above the board
surface (these blemishes are colloquially known as “nail pops”).
TOOLS
Gypsum board installation and finishing require only some basic tools. While there are also
many specialized hand and power tools available for gypsum board installation, here’s a list with
brief descriptions of the basic tools necessary for a typical wallboard job:

9. Measuring tape – A steel retractable measuring tape, usually 25 feet in length.
Gypsum board T-square –Square edge for measuring and cutting gypsum board to length and for
cutting out holes for square outlet boxes and other openings.
Utility knife – Standard cutting tool with replaceable/reversible blades for scoring and cutting
gypsum board.
Hammer – Drives nails through gypsum board into wood framing.
Keyhole saw – Small triangular saw for cutting out holes for outlet boxes, pipes, and other
penetrations.
Rasp – A tool for smoothing rough edges of wallboard after it has been scored and snapped.
Assorted trowels and taping knives – Bladed tools for applying and smoothing tape and joint
compound over joints and fastener heads.
Mud tray – Box to contain joint compound while finishing joints and fastener heads.
Sanding pole – Tool that enables sanding walls from floor to ceiling and standard height ceilings
without the use of a ladder.
Screw gun – Power tool that drives all types of gypsum board screws through gypsum board and
into framing or substrate.
Drywall Installation and Finishing Tools
Application Sequence
Use the following procedures
to ensure a successful
gypsum board application:
1. Install ceiling panels first,
then the wall panels.
2. Once cut to size, position
gypsum boards into place
without forcing them.
3. Match similar edges and
ends, i.e.: tapered to tapered,
square-cut ends to square
ends.
4. Plan to span the entire

10. length of ceilings or walls with single boards if possible to reduce the number of butt joints,
which are more difficult to finish. Stagger butt joints and locate them as far from the center of
the wall and ceiling as possible so they will be inconspicuous.
CUTTING AND FITTING PROCEDURES
Gypsum board installations require careful planning: accurate measuring, cutting and fitting are
very important. In residential buildings with ceiling heights under 8′1″, wallboard is best
installed at right angles (perpendicular) to framing members as this orientation of the panels
leaves fewer joints to finish. On long walls, horizontally attaching boards of the maximum
practical length will minimize the number of butt joints. Avoid using damaged board.
Carefully measure where board ends and edges will meet corners and ceilings. Accurate
measuring reveals irregularities in framing and furring that require corrective allowances when
cutting boards. Correct poorly aligned framing before attaching gypsum board
Fig. 6 – Measuring from Edge before Cutting Board
To cut gypsum board, working from the face side , first score the board by cutting through the
paper to the core with a sharp knife (Fig. 7).

11. Fig. 7 – Using Utility Knife to Score Board
Then snap the board back and away from the scored cut on the face of the board(Fig 8).
Fig. 8 – Snapping Scored Board
Sever the board’s backing paper by snapping the board in the reverse direction or by cutting the
backing paper with a scoring knife. Gypsum board may also be cut using a hand saw. Smooth all
cut edges and ends of the gypsum board to form neat, tight-fitting joints when installed. Smooth

12. ragged ends or broken edges with a rasp or sandpaper, or trim them with a sharp knife. If burrs
on the cut ends are not removed, they will form visible ridges in the finished surface.
Single-Ply and Multi-Ply Application
In light commercial and residential construction, single-ply gypsum board systems (Fig. 9) are
the most commonly used wall and ceiling systems. Usually such systems meet fire resistance and
sound control requirements2
. Multi-ply systems (Fig. 10) have two or more layers of gypsum
board that will typically increase sound isolation and fire resistive performance.Multi-ply
systems also provide better surface quality because face layers are often laminated over base
layers, so fewer fasteners are needed to attach the face layer. As a result, surface joints of the
face layer are reinforced by the continuous base layers of gypsum board. Nail popping and joint
ridging problems are less frequent, and imperfectly aligned supports have less effect on the
finished
surface.
Fig. 9 – Single-Ply Application

13. Fig. 10 – Multi-Ply Application
Ensure satisfactory results with either single-ply or multi-ply assemblies by requiring proper:
·framing details (straight, correctly spaced, properly cured lumber)
·job conditions (controlled temperature and adequate ventilation during application)
·application of the board (measuring, cutting, aligning, fastening)
·joint and fastener treatment
·special requirements for proper sound isolation, fire resistance, thermal properties, or moisture
resistance.
Control Joints
Ceilings exceeding 2500 sq. ft. in area, and partition-, wall-, and wall-furring runs exceeding 30
ft. all require control joints. Do not exceed 50 ft. between ceiling control joints in either
direction. Install a control joint wherever ceiling framing or furring changes direction. Do not
exceed 30 ft. between control joints in walls or wall furring. Be sure to install a control joint
where an expansion joint occurs in the base of an exterior wall. Wall- or partition-height door

14. frames may serve as control joints. Whenever possible, ensure that control joints coincide with
any building control joints. NOTE: Where a control joint occurs in an acoustically rated
assembly, provision may be necessary to block the sound at the joint opening by using backing
material, such as gypsum board, mineral fiber or equivalent, or filling the void created with
resilient insulating material.