1. The tough, fibrous cellular substance that
makes up most of the stems and
branches of trees beneath the bark.
WOOD
2. • Tongue and groove
A method of fitting similar objects together, edge
to edge, used mainly with wood,
in flooring, parquetry, panelling, and similar
constructions. Tongue and groove joints allow
two flat pieces to be joined strongly together to
make a single flat surface. Before
plywood became common, tongue and groove
boards were also used for sheathing buildings
and to construct concrete formwork.
• click system
A method of joining boards together without the
use of glue. The tongue is made with a
protrusion that fits over a corresponding rebate
in the groove.
WOOD INSTALLATION
3. • plywood
A wood panel product made by bonding veneers together under heat
and pressure, usually with the grain at right angles to each other and
symmetrical about the center ply.
WOOD FABRICATION
• group number
A number identifying one of five
groups of species used for the
face and back veneers of a
plywood panel, the species being
classified on the basis of bending
strength and stiffness, with Group
1 containing the stiffest species
and Group 5 the least stiff.
• exterior plywood
A plywood panel consisting of C-
grade veneers or better, bonded with
a fully waterproof glueline for
permanent exposure to weather or
moisture
• interior plywood
A plywood panel made with D-
grade veneers or better, bonded
with an exterior, intermediate, or
interior glueline.
4. VENEER GRADE
A grade defining the appearance of a veneer in
terms of growth characteristics and the number
and size of repairs that may be made during
manufacture.
• N-grade
A smooth softwood
veneer of all
heartwood or all
sapwood, free from
open defects with
only a few well-
matched repairs.
• A-grade
A smooth, paintable softwood veneer with
a limited number of neatly made repairs
parallel to the grain.
• B-grade
A softwood veneer having a solid surface
with circular repair plugs, tight knots, and
minor splits permitted.
• C-grade
A softwood veneer having tight knots and knotholes of limited
size, synthetic or wood repairs, and discoloration and sanding
defects that do not impair the strength of the panel.
• C-plugged grade
An improved C-grade softwood veneer having smaller knots and
knotholes, some broken grain, and synthetic repairs.
• D-grade
A softwood veneer having large knots and knotholes, pitch
pockets, and tapering splits.
5. • decorative plywood
Hardwood-faced plywood manufactured for use as
paneling or in cabinetry and furniture.
• veneer
A thin sheet of wood rotary cut, sliced, or sawn
from a log or flitch and used as a superior facing
to inferior wood or bonded together to form
plywood.
• crossband
A layer of veneer immediately adjacent to and at
right angles to the face plies in a plywood panel.
• core
The center of a plywood panel, consisting of
veneers, saw lumber, or composition board.
• banding
The solid wood stock extending around the sides
of a veneered panel, concealing the core and
facilitating the shaping of the panel edges.
6. • matching
Arranging sheets of veneers
so as to emphasize the color
and figure of the wood.
• book matching
Arranging veneers from the same flitch
alternately face up and face down to
produce symmetrical mirror images about
the joints between adjacent sheets.
• herringbone matching
Book matching in which the figures in
adjacent sheets slope in opposite
directions.
• slip matching
Arranging adjacent sheets of veneer from
the same flitch side by side without turning
so as to repeat the figure.
• diamond matching
Arranging four diagonally cut sheets of a
veneer to form a diamond pattern about a
center.
• random matching
Arranging veneers to intentionally create a
casual, unmatched appearance.
• figure
The natural pattern on a
sawed wood surface
produced by the intersection
of annual rings, knots, burls,
rays, and other growth
characteristics.
7. • treated wood
Wood that has been coated or impregnated with chemicals to improve its
resistance to decay, insect infestation, or fire.
• pressure-treated wood
Wood impregnated with chemicals applied under pressure to reduce its
resistance to decay and insect infestation.
• non-pressure-treated wood
Wood coated, dipped, or impregnated with a preservative under atmospheric
pressure.
• Fire-retardant wood
Wood treated with minerals salts impregnated under pressure to reduce
flammability or combustibility. The salts react chemically at temperatures
below the ignition point of the wood to break down into water and carbon
dioxide.
WOOD MAINTENANCE METHODS
AND TECHNIQUES
8. • full-cell process
A process for pressure-treating wood in which a vacuum is first drawn to
remove air from the wood firers and allow the preservative to be absorbed
by the cell walls, after which pressure Is applied to force additional
preservative into the cell cavities. The full-cell process leaves the maximum
amount of preservative in the wood.
• empty-cell process
A process for pressure-treating wood in which the pressure of the entering
preservative entraps air in the wood fibers, which expands when the
pressure is released to expel excess preservative from the cell cavities. The
empty-cell process yields a drier product while ensuring deep, uniform
penetration of the preservative.
• vacuum process
A non-pressure treatment in which a vacuum or partial vacuum exhausts air
from the cells and pores of the wood while atmospheric pressure forces
preservative into the wood.
WOOD MAINTENANCE METHODS
AND TECHNIQUES CONT.
9. • preservative
Any various
substances for coating
or impregnating wood
in order to protect it
against wood-
destroying fungi and
insects
• water-borne preservative
An inorganic, water-soluble
compound, as ammoniacal copper
arsenite (CCA), used as a wood
preservative. ACA and CCA affix
chemically to the wood cell walls
and is resistant to leaching. The
copper acts as a fungicide while the
arsenate is toxic to wood-destroying
insects. Wood treated with ACA and
CCA is odorless and paintable.
• oil-borne preservative
An organic chemical dissolved in a
petroleum oil carrier, such as
pentachlorophenol or copper
naphthenate,used as a wood
preservative. Pentachlorophenol,
the most commonly used oil-borne
preservative, has a persistent odor,
is Insoluble in water, and is highly
toxic not only to fungi and insects
but also to humans and plants.
• creosote
An oily liquid of aromatic
hydrocarbons obtained by distillation
of cool tar, used as a wood
preservative for marine installations
or odor severe exposures to wood-
destroying fungi and insects.
Creosote and creosote solutions
have a penetrating odor and render