AIR DRY
A Method of drying timber by atmospheric conditions between
its natural state as a tree and its use in building. Air-dried timber
is not usually sufficiently dry for hardwood flooring and kiln drying
is required to achieve a moisture content of 8 to 10%,
which conforms to BS8201.
ACCLIMATISATION
The procedure of placing wood flooring in the area where
it is to be installed to enable it to "acclimatise" or adjust its
moisture content to correspond with that of its surroundings.
When acclimatising wood flooring, the boards should be
separated in such a manner as to enable air to circulate
around them. Acclimatisation procedures vary according to
individual products - guidance on this should be sought from
your supplier.
ADHESIVE
Paste used for fixing flooring to its subfloor. Usually spread with
a notched trowel - it is important to use a trowel with the correct
sized notches so as to apply the correct quantity of adhesive.
ADHESION
The bonding of one material to another. This is affected by
the conditions of the surfaces to be coated, the closeness of
the contact, temperature and humidity. Ideally adhesives
should be solvent and water free.
APPLICATOR
An implement for applying adhesive, oil, seal or other dressing
ARCHITRAVE
A wooden frame for doorways. Usually requires
undercutting to permit wood flooring to fit under it.
BATTEN
A piece (usually) of softwood which supports the hardwood
flooring and to which it is often fixed by nailing.
BEVEL
A decorative feature whereby the sharp edge of the board is
planed off. The bevel more clearly defines the boards edge,
but this can add to the beauty of the floor. Sometimes also
called an “eased” edge. There is no industry standard for
bevel size, so it varies from producer to producer - however,
it is usually angled at 450 and between 0.5mmand 2mmdeep.
BIRD'S EYE
A distinctive figure in Maple wich is said to look like a bird's eye.
BLEACH
The process by which a chemical is applied to timber in order
to lighten it. Certain Hardwoods are bleached by sunlight – ie
Walnut, Cherry and Oak.
BROWN OAK
A distinctive type of Oak that is a deep, chocolate colour.
English Brown Oak is actually white oak that has turned
brown due to a fungal infection (Beef steak fungi) that causes
a chemical change in the tree. It is a rich honey brown colour.
BLOCKS OR PARQUET WOOD BLOCKS
Pieces of flooring timber, varying in size, but usually in the
region of 200-275mm x 65-75mm x 20 mm. Most blocks
are tongued and grooved (see below) and adhered to a
screeded subfloor with adhesive. Can be laid in different
patterns; Basket weave, Herringbone, half bond etc.
BOARDS (or PLANKS or STRIPS)
A form of wood flooring composed of elements from 60-
200mm wide (sometimes smaller or larger) and from
500mm to 2500 mm in length, often random lengths.
Boards can be secret nailed (see below) or glued. Solid
boards must never be fixed by the “floating floor” method.
BORDER
A feature in a floor, whereby a contrasting timber is inset
around the perimeter. Sometimes called an “inset strip”.
BRINELL SCALE OF HARDNESS
A scale that compares the hardness of various species of
timber. On the Brinell scale, oak has a value of 5 whereas
Jatoba has a value of 7 indicating Jatoba is harder than Oak.
CASE HARDENED
Case hardened is used to describe timber that has been improperly
dried. If dried too quickly,wood shrinks heavily on the surface
compressing its still damp interior.This results in unrelieved case hardened
wood which may warp considerably and potentially dangerously
when the stress is relieved by sawing. This is a commonly known
term, but case-hardened timber is not as common as people think.
CELLULOSE
The carbohydrate that is the principle constituent of wood.
It forms the frame work of wood cells.
CHECK
A lengthwise separation of the wood which extends across
the rings of annual growth, usually resulting from stress, set
up in wood during seasoning.
CHIPBOARD
A board made from particles of wood, mechanically
compressed with glue or other binders to produce a board.
Chipboard is a very common subfloor material today,
particularly in new construction. It should be avoided in damp
conditions although you can source flooring grade chipboard
that is damproof. Serrated nails are recommended when fixing,
as chipboard does not retain standard nails well.
Resin-bonded ply is an alternative.
CITES LIST
List of woods that are considered to be endangered.www.cites.com
CLICK JOINT
A method of joining the boards of floating floors together
without using glue. The tongue is made with a protrusion that
fits over a corresponding rebate in the groove, so called
because the elements often "click" when pushed together.
Not recommend for use with solid boards as the precise
jointing mechanism is susceptible to slight changes in
moisture – rendering the system useless.
CLOSE-PILING
Piling (stacking) of wet timber (not kiln-dried) without sticks,
even for a few days is a cause of staining and if prolonged,
may result in serious losses from fungal decay.
CLOUT NAIL
A type of galvanised nail with a large head, sometimes used
as a decorative/period feature when face fixing solid boards.
COEFFECIENT OF EXPANSION
Timber expands and contracts with changes in moisture.
The rate of this change varies according to a timbers porosity.
The rate of this change can be measured to produce a table
showing the varying coefficient of expansion - it is measured
by the change in the width of a board that happens when the
moisture content goes from 20% to 10%. Beech has a high
coefficient whereas Oak has a low one. In layman’s terms this
could be called a timbers “stability”.
COSHH SHEET
The manufacturer's guide to the safety aspects of the product,
produced in accordance with the Control of Substances
Hazardous to Health.
CONDITIONING
A process usually used at the end of the drying process used
to create an equilibrium moisture content.
CRACK
A wide gap in the timber, often caused by shrinkage of timber
containing a shake.
CROWN CUT
A method of slicing veneers whereby the average inclination for the growth rings to the wider face is tangential or less
than 45°. This method is also known as flat cut.
CROWNING
Distortion of boards or blocks so that the surface is convex.
Usually caused by very damp atmospheric conditions,whilst the
subfloor remains dry.
CUMULATIVE SHRINKAGE
Cumulative shrinkage or "rafting" is caused by a lacquer
applied to the surface of a floor, running down the edges of
the pieces and sticking them together like strong glue. When
the floor shrinks (with its natural seasonal movement) instead
of each piece shrinking a fraction so that there is a tiny gap
between each piece, the pieces are stuck together in "rafts"
and wide gaps open at weak spots. It is sometimes possible
to fill the gaps, but floors subject to bad cumulative shrinkage
may have to be completely replaced.
CUPPING
Cupping is the opposite of crowning and is infinitely more
common. It is almost always caused by moisture under the
floor, whereby the moisture content of the bottom of the
board is raised to a higher level than the surface, distorting
the board. Whilst minor cupping, less than 0.5% of the board
width, might be sanded out, there is a slight danger that, if the
board should return to a stable form, crowning might result.
DAMP PROOF MEMBRANE
A layer of impervious material, often polythene, built into the
subfloor to prevent moisture affecting the flooring. Liquid
DPMs are recommended when the existing moisture content
of the screed is too high to fit a timber floor. BS8201 advises a
slab moisture content of 4%or 75%RH. However, for flooring
with a moisture content of 8 to 10%a slab must not exceed a
moisture content of 2%or 40%RH. Residual moisture content
in a newly laid concrete slab can be sealed with a proprietary
product, but rising damp will need to be treated by a specialist.
DATA SHEET
The manufacturer's guide to the technical details of the product.
Db VALUE
The measurement of the floor's sound insulative properties.
Db = decibel – a unit of sound measurement. There are
various sound reduction underlays available that will enable
the use of a timber floor whilst meeting all of the current
sound reduction regulations.
DIFFERENTIAL SHRINKAGE
Different cuts of the same wood species can shrink at different
rates. The most stable section is the 1/4 sawn section, this is
far more stable than a plain sawn section. Different species of
timber expand and shrink at different rates.
DIMENSIONAL STABILITY
This refers to the varying propensity of different wood floors to
expand/contract. For example, wide engineered wood floors
are more dimensionally stable than wide solid boards. Installation
methods will/should reflect on a products dimensional stability.
ENDS MATCHED
The Tongue & Groove profile on the end of a board. This profile
on structural flooring enables individual planks to straddle a
joist, rather than being cut back to end on an individual joist
which is wasteful.
ENGINEERED (BOARDS)
When boards were introduced having a 3 mm or 4 mm
hardwood surface, a 7 mm softwood core at right-angles
to the hardwood and a 3 mm ply backing, they were called"Laminated Hardwood Boards" With the advent of plastic
Laminate Flooring, the word "Laminate" or "laminated" has
become synonymous with this cheaper imitation of wood
flooring. In order to avoid confusion, the original hardwood
variety became known as "Engineered" boards, because
they are manufactured. Subsequently, there was a move to
use the name "Multilayer" which we believe is a more
accurate description of the product. However, the term“Engineered” is still widely used. Engineered boards can be
laid as a floating floor, because they are very stable, due to
their cross-grained construction. The boards are far more
dimensionally stable than solid boards and as such can be
installed by the “floating floor” method of installation.
Structural engineered boards are now also available; they are
usually made with a plywood backing. These boards can
have a thicker wear layer and can also be laid over joist.
EXPANSION
Wood is a hygroscopic material. It expands only due to the
absorption of moisture, and shrinks when it loses moisture.
In the UK, the moisture content of wood flooring is at its highest
in summer, when windows and doors are open and the air
relatively moist; it is at its lowest in winter, when windows
and doors are closed and central heating is running on full,
creating very dry air. A moisture content of 8 to 10%
assumes a humidity level of 35 to 65%. So if during winter
you fail to “air” your rooms and the humidity drops to under
35% shrinkage will occur - at 20% major damage to all floors
is evident (even engineered).
EXPANSION GAP
A gap left at the perimeter of a wood floor to allow for seasonal
expansion. The gap is usually 15 mm or 3mm per line arm across the grain.
F.A.M.C
Fair and average moisture content. Any moisture content is
always an average of different readings across a batch of products,
and this is why a spread of content is detailed - ie 8 to 10%. This
figure is still only an average and therefore can still contain some
boards with a higher or lower reading than 8 to 10%.
FACE NAIL
Boards nailed through the surface. Nails are usually punched
and filled. Often necessary with boards exceeding 100 mm
in width in order to comply with the requirements of
BS8201:1987 which states that boards exceeding 100 mm
in width should not solely be secret nailed. This requirement
is now seen as being restrictive as widths up to 180mm are
successfully secret nailed. In this instance, the humidity levels
of both the sub-floor and air are crucial.
FIBRE SATURATION POINT
This is the theoretical point when the cell cavities are empty of free
water and the cell walls remain saturated. The average moisture
content of wood at moisture saturation point is between 23 to 30%.
FIGURE
The beautiful appearance of the timber created by the grain and
growth rings. Certain timbers have particular figures, eg the"bird’s eye" figure in Maple ormedullary rays in 1/4 sawn Oak.
FILLET
A fillet is a small batten (see above) often used on joists in
order to pack up the floor level.
FLOATING FLOOR
Wood flooring loose laid over a resilient underlay .Engineered or Multilayer boards are usually laid as floating
floors, but never solid hardwood boards. Floating floors laid
over concrete must include a vapour barrier. The boards that
constitute a floating floor must be fixed together, usually by
glueing the tongues and grooves.
FLOOR SEAL
A heavy-duty lacquer applied to the surface of wood flooring. Usually
maintained by sweeping and damp-mopping. Can be very hard wearing.
FSC
Forestry Stewardship Council: Independent membership
based organisation promoting responsible management of
the world's forests through developing standards and a
certification system.
GRADING
There are various grades of timber, variously called prime,
first, second, country, factory etc. There are no British
Standards or industry standards for wood floor grades – so
you need to check what the grades include/exclude. It is also
important to remember that grades are species specific – ie
Prime Oak might not contain either knots or sapwood but
Prime Walnut might allow for some of both.
GREEN
This is a general term for unseasoned timber. Green timber
cannot ever be used internally for wood floors.
GRIT
A term used to describe sandpaper, the lower the grit
number - (ie 40) - the more coarse the paper.
HARDWAX OIL
Oil finishes are an ideal alternative to floor seals or lacquers,
where a more natural appearance is desired. Oil finishes
usually require marginally more maintenance than floor seals,
but when properly maintained, can last longer. Hardwax oils
can be easily re-coated and ‘spot repaired’. Please note that
UV oil finishes are not compatible with hardwax oils. The
closed surface of the UV finish restricts the hardwax oil from
penetrating the wood – which results in drying difficulties
as well as heavy residues left on the surface of the floor.
HEADER JOINT
The joint between two ends of boards.
HEART
The core of the tree from which growth rings emanate.
HYDROSCOPIC
When wet wood is exposed to dry air it loses water to the air
and when dry wood is exposed to humid/damp conditions it
absorbs water and swells.
HYGROMETER
A device for measuring the moisture content of air.
Hygrometers are calibrated in % relative humidity or rh.
Hygrometers used in flooring consist of a polystyrene box
about 300 x 300 x 75 mm which traps air in a void under the
box. The humidity box, as it is called, is fixed to a subfloor
with an adhesive sealant strip and left for 12-60 hours.
Moisture from the subfloor exchanges with the air above it
until the two are in equilibrium, so that ascertaining the moisture
content of the air under the box is the same as testing the
screed itself. The British Standard code of practice for the
installation of hardwood flooring (BS8201:1987) specifies
that the rh should not exceed 75% when flooring is to be laid
on a screed. With the modern practice of glueing boards
directly to a screed, this is considered by many to be too high
and 70% is more realistic for this purpose. As an alternative
to humidity boxes, humidity sleeves are now in common use.
HONEYCOMBING
Interior checks caused when timber has been case hardened.
The outer zones of the wood set without shrinking and when
the centre core dries, it is restrained from shrinking and interior
checks may result.
INLAY
Feature of contrasting wood inset into a floor.
INSULATION
A layer of material, often built into the subfloor as a barrier for
heat or sound.
JOIST
A joist is a wooden strut, nowadays usually softwood, used
to support floorboards to which the boards are usually
nailed. The size of the joist will depend upon the expected
load and the span.
KILN
A chamber in which the temperature, humidity and
movement of air is controlled and is used to dry wood.
KILN DRIED
Timber for wood flooring is usually dried in a kiln to reduce its
moisture content to 8%-10%. This level is selected because
it is the moisture content wood flooring usually assumes in buildings in the UK. In excessively dry conditions wood flooring
will reduce to a moisture content of 5% - at this level
significant gaps will appear, even in timber that has originally
dried in accordance with British standards.
KNOT
A knot is a figure in the grain of wood where a branch once
grew, created during the growth of the tree. Small knots or
burrs can be quite attractive; Some timbers, like Cherry, contain
many knots; others. like Birch, very few. The knot content in
timber can vary depending on the specific tree variety and is
usually controlled in the grading process during production.
LACQUER
Another name for floor seal. Lacquers are often
polyurethane- based in a water-borne solution.
LAMINATE
This is a plastic imitation wood flooring which has become
popular in recent years, due mainly to its competitive pricing
structure. However, whilst its general appearance is good,
being produced photographically to look like wood, it lacks
the warmth and resilience of real wood and cannot, of
course, ever be sanded.
LAMINATED
See "Engineered Boards" above.
LATEX SCREED
When floor layers are faced with solid subfloors that are not
sufficiently flat, they use a smoothing compound. Smoothing
compounds, or as they are often incorrectly called, self-levelling
compounds, are latex-cement powders which are mixed,
either with water or latex paste, to form form a grey cement
which can be applied with a screeding trowel in thicknesses
of 3 mm, in some cases even less.
MICRO BEVEL
Very small bevel. See bevel above.
MEDULLARY RAY
Iridescent streaks found in quarter sawn material.
MULTILAYER
See "Engineered Boards" above.
MOISTURE CONTENT
The amount of moisture contained in a material. The moisture
content of most wood flooring is 8%- 10%. The moisture content
of a screeded subfloor when laying wood flooring ought not to
exceed 40% rh which is about 2%.
MOISTURE METER
A device used to measure the amount of water in a particular
material. Moisturemeters used in flooring are calibrated to a
scale called "wood moisture equivalent" (wme). This is because
wood is fairly consistent with regard to moisture content, even
within different species,whereas of the materials, like sand/cement
or plaster, vary according to their particular composition.
Consequently, they are measured on the wme scale which would
be equivalent to the moisture content a piece of wood would
assume if placed in contact with the material being tested.
MOISTURE GRADIENT
The variation in moisture content between the surface and
the core of a piece of wood.
MOVEMENT
Movement is the swelling or shrinkage when wood is
exposed to various humidity conditions. (See hydroscopic
moisture).
NAILER
There are various nailing machines on the market, perhaps
the best known of which is Portanailer which drives nails into
the flooring at exactly the correct angle. Machines can be
either manual or pneumatic.
NEWTON
A measurement of force. For the technically minded, it is the
amount of force that imparts the acceleration of 1 meter per
second to a mass of 1 kilogram.
NOTCHED TROWEL
The reason for applying adhesive (and other materials) with a
notched trowel, is that the manufacturer of the product will
have calculated the optimum quantity of adhesive required,
and applying it with the correct notched trowel will ensure
that exact quantity is applied, thus ensuring a perfect bond.
OIL
A preparation for finishing wood floors. (See also "Hardwax
Oil" above). There are many different types of oil on the
market. It is important to know the requirements of the floor
and recommended maintenance procedure. Different oils
have varying “high solid” content. The high solids are the wax
residues that are left once the “spirit” (or carrying agent), has
evaporated
PARQUET FLOORING
Parquet flooring is formed from battens, usually 200-300mm
x 60-100mm x 6mm or 10mm in thickness. Traditionally,
parquet battens were face pinned and glued to wood
subfloors, but today they can be laid over solid subfloors too.
Traditionally laid in a herringbone pattern, but can be laid in
many patterns and often with a border. Parquet flooring is
also made in many elaborate patterns, eg Versailles. Parquet
has also, incorrectly, become a generic term for wood flooring.
P.E.F.C
Certification system, providing assurance to consumers that
wood used comes from sustainably managed forests.
PENNY JOINTS
Often called "washer joints", these are gaps left between
every board, or every few boards, for additional expansion
provision within the body of a boarded floor. They are called"penny" or "washer" joints, because pennies or washers
were used in order to achieve an even gap. Can also be left for
decorative purposes to create a traditional/restoration look.
PIPPY
Small clusters of knots, that are collectively called Pips or
burrs. The very heavy concentrations are called Burrs. Usually
desired in Oak but also found in Elm and Sycamore. It is also
mainly found in the United Kingdom and is rarely found in
either Europe or North America. They can also be described
as cats paws – as they look like the paw prints of cats.
PLAIN SAWN
The way the raw log is sawn into planks. The two most
common formats are plain sawn and quarter sawn. Plain
sawn material is the cheaper cut. The log is sawn into slices
right across. Quarter sawing involves cutting each plank on
the line of a radius from the centre of the log.
PLY
A laminated board consisting of thin layers of board bonded
together. In flooring, 6 mm ply is the most common for
underlay purposes over, for example, a floorboard subfloor.
Ply can be resin-bonded or WBP (water & boil proof) which
means the ply should be unaffected by moisture.
PORTANAIL
See "nailer" above.
PROTIMETER
GE- Protimeter are one of the worlds leading manufacturers
of moisture-testing equipment. They manufacture hygrometers
(see hygrometer" above) as well as moisture meters (see"moisture meter" above).
QUADRANT
A quarter-round beading used in flooring installations to
cover the allowed expansion gap. It is usually the same
species of timber as the floor, or as near in shade as possible,
and is pinned to the skirting.
QUARTER SAWN
True Quarter Sawn oak boards are cut so that the end grain is
at an angle of 90O to the face board. This produces wonderfully
straight grained planks. Medullary rays (the iridescent streaks)
are then visible as swirls running across the width of the
board. The joinery in Cathedrals, Palaces and fine houses was
produced from the finest quality quarter sawn oak.
RANDOM LENGTH
Boards which vary in length within one floor.
RANDOM WIDTH
Boards which vary in width within one floor. Historically
through and through, cut planks produced lots of different
widths of boards.
RAFTING
See "Cumulative Shrinkage" above.
RELATIVE HUMIDITY
Humidity in the air is measured using an hydrometer. The
amount of moisture air can contain varies according to its
temperature. Warm air can hold more moisture than cool air.
Warm air gives up its moisture as it cools, so that if warm air
comes into contact with a cool surface, we get condensation.
The measurement of the quantity of moisture in air is
expressed relative to its maximum capacity to contain
moisture which would be 100% relative humidity.
RIFT SAWN
As per quarter sawn but with an angle of just under 90O -
producing straight grained boards without the medullary rays.
RESIDUAL DAMPNESS
Moisture remaining within a screed even though the surface
appears dry.
RIPPLE
A slight irregularity in the surface of a hardwood floor often
caused by inefficient sanding.
RIPPLED
An unusual type of figure that looks like a ripple across the width
of a plank. Highly prized and found in Maple and Sycamore.
RISING DAMP
Occurs in screeds that do not have an effective damp proof
membrane. Sub-floor Preparation products that pre-seal
damp screeds will not (in the long run), stop damp from
affecting a wood floor.
SAMPLE
A sample is one of a number of pieces set in a kiln or air
drying stack used to measure the loss of moisture.
SAND
To grind the surface of a wood floor with sandpaper so as to
smooth the surface ready for the application of a dressing.
Usually carried out using a sanding machine.
SAP
The liquid part of a tree. Visible as the light timber on the
outer edges of the planks.
SCOTIA
A beading, used for the same purpose as a quadrant bead
(see above) but concave shaped instead of convex shaped.
SCREED
Usually refers to the subfloor, which may be a sand and
cement screed. Must be dry (below 75% relative humidity)
before wood flooring is laid on it. Must be sound and flat too.
May also be a latex or other smoothing screed.
SCREEDING TROWEL
A trowel with a smooth surface and without notches for
applying sand and cement, latex or other smoothing screeds.
SCREEN
Similar to sanding, but usually done with a rotary disc using
very fine abrasives. Ideal for sanding old floors when you
want to carefully remove layers of Patina.
SEAL
Common name for polyurethane-type lacquers applied to
wood flooring.
SEASONING
The process of drying timber either naturally or in a kiln, to a
moisture content appropriate for the conditions and purposes
for which it is to be used. For hardwood flooring in the UK,
this usually means 8% - 10% moisture content. “Seasoned
timber” is also used as a description of timber that has been
air dried for a long time.
SECRET NAIL
The method of nailing tongued and grooved boards through
the tongue so that the nails cannot be seen in the finished
floor. See also "Portanail" above. Note that BS8201:1987
states that boards of less than 100 mm in width can be
secret nailed as their sole method of fixing.
SCREW & PLUG
The method of concealing screws used in face-fixing wood
flooring. The screw is countersunk below the surface of the
board and a plug of the same grain and shade as the board is
fitted over the screw.
SELF-LEVELLING COMPOUND
See "latex screed" above.
SERRATED TROWEL
See "notched trowel" as above.
SHAKE
A natural defect in a board, shakes are small cracks in the
material. They are unavoidable in many species and may
open when the board shrinks.
SHRINKAGE
When wood dries the removal of moisture causes the wood
to shrink. Shrinkage normally starts at Fibre saturation point
(25/30%). All timber shrinks more tangentially than it does
radially whereas shrinkage longitudinally is negligible. As a
result of the different shrinkage rates radial and tangential,
you get different shrinkage which will cause square timber to
diamond, but if wood shrank evenly in each section, this
would not happen. Every species of wood has a different
rate of shrinkage.
SKIRTING
The wooden board (usually) fixed to the bottom of walls.
If the skirting is removed before the laying of the floor, the
required expansion gap can be left underneath so that no
additional beading is required. Various moulded profiles are
available including – pencil round, torus, lambs tongue, etc.
SMOOTHING SCREED
A powder, often cementitious, mixed with either water or a
latex paste, depending upon its type, and used to prepare
uneven screeds to a smooth surface. Often called a levelling
or self-levelling screed, but this is incorrect as it is very
difficult to level floors with such a product. There are
companies who pump similar materials onto floors and
this procedure will actually form a level base.
SPALTED BEECH
Spalting is the result of fungi growing on the tree. The black
lines are the result of the roots of the fungi dissolving the
wood in order to feed on the nutrients released. It affects
both the colour of the wood and the hardness.
STEAMING, FUMING AND HEAT TREATING
Processes often used on timber, especially Oak. The
procedures both darken the timber and strengthen it.
STERLING BOARD
A type of particle board, used for subfloors.
STICK MARKS
When wood is stacked for drying, sticks are placed between
the boards to enable air to circulate all round. Sometimes
these sticks cause marks in the timber itself. This is usually
when the wrong species of stick has been used that causes
a reaction with the boards being dried.
SUBFLOOR
The surface onto which the decorative wood flooring is laid.
SURFACE DPM
If screed is tested with a hygrometer (in accordance with
BS8201) and found to be wet, a surface DPM might be used,
subject to circumstances. Such products may be liquids, eg
epoxy DPM's, or underlays, such as System Platon or Uzin
interlayers.
SUSTAINABLE SOURCE
A source of wood flooring where new trees are continuously
planted to replace those cut down.
TAR OR BITUMEN-CENTRE BUILDING PAPER
Used over wooden subfloor as a vapour barrier. Whilst nails
puncture polythene, the bitumen centre in this material clings
to the nails. It is now accepted that floors laid on joist that are
vented should be laid on building paper.
THRESHOLD STRIP
A piece of shaped wood, placed in a doorway so that a
higher level wood floor can be smoothly finished to a lower
adjoining floor.
TONGUE & GROOVE
A method of joining individual pieces of wood together in a
floor to form a homogeneous unit. The tongue is cut from the
edge of the block or strip to project outwards. The groove, in
the opposite side is made to fit the tongue snugly, but not too
tight. Tongues and grooves are always on the long edges; if
they are on the ends as well, the material is said to be "ends
matched". In floating floors, where tongues and grooves are
glued together, the groove has a void at the inside to
accommodate the glue and prevent it from being squeezed
to the surface. The tightness of the tongue and groove is
called the tolerance. There is no industry standard for the
amount of tolerance in a tongue and groove joint.
T-STRIP
A strip placed in a doorway between two adjoining wood
floors of the same level. Permits the inclusion of an expansion
gap in the doorway.
UNDERLAY
A Material placed under a wood floor to smooth the subfloor (eg
ply), to protect against damp (eg polythene) or as a resilient layer
under floating floors. Can also help to cut down airborne noise.
UV DRIED
A Method of rapid-drying lacquer in the factory which produces
a harder wearing surface. Modified Oils can also be UV dried.
WAX
A paste applied to the floor surface which protects the wood
from traffic wear. Superseded in the 1980s by polyurethane
and other lacquers and due to the latter needing less maintenance,
it is now rarely used but substituted by Hardwax Oil.
Waxes improve the luster of a floor and are used to create a
period, restored feel. Several coats are applied to build up the
finish, which is then polished either mechanically or by hand
to create a warm, shiny floor.
WEAR LAYER
The layer of wood nearest the surface in a multilayered board
which receives the foot traffic. Wear layers are normally
quoted on a “nominal” thickness basis– this means the
thickness before sanding. A wear layer can also be measured on
a solid board as being the thickness of wood above the tongue.
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