Wood Flooring – Terminology Made Easy

Categories: Advice

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 – 10%, which conforms to BS8201


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.  Acclimatisation procedures vary according to individual products – guidance on this should be sought from your supplier


paste used for fixing flooring to its sub-floor.  Usually spread with a notched trowel – it is important to use a trowel with the correct sized notches to apply the correct quantity of adhesive


a wooden frame for doorways.  Usually requires undercutting to permit wood flooring to fit under it


a decorative feature whereby the sharp edge of the board is planed off.  The bevel more clearly defines the board’s 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 45o and between 0.5mm and 2mm deep

Blocks or Parquet Wood Blocks

pieces of flooring timber, varying in size, but usually in the region of 200 – 275mm x 65 – 75mm x 20mm.  Most blocks are tongued and grooved and adhered to a screeded sub-floor with adhesive or face nailed.  Can be laid in different patterns – basket weave, herringbone, half bond etc


a feature in a floor, whereby a contrasting timber is inset around the perimeter – sometimes called an “inset strip”


is designed to highlight natural richness and deep grain of white oak. In wire brushed flooring, a soft portion of the wood is removed to expose the grain and bring enhanced definition to each plank. Beautiful knots and dramatic oak character marks further emphasise depth and texture of wire brushed flooring

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


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 – 10% assumes a humidity level of 35 – 65%

Expansion Gap

a gap left at the perimeter of a wood floor to allow for seasonal expansion


fair and average moisture content.  Any moisture content is always an average of different readings across a batch of products, and therefore a spread of content is detailed – i.e. 8 – 10%. This figure is still only an average and therefore can still contain some boards with a higher or lower reading than 8 – 10%

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


Forest Stewardship Council

an independent, non-governmental, not-for-profit organisation established to promote the responsible management of the world’s forests


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

Header Joint

the joint between two ends of boards

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, even in timber that has originally dried in accordance with British Standards


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


gives the floor a refined, silky gloss finish and optimal protection against dirt and mechanical stress.  The lacquer finish is fully closed yet highlights the fine wood grain.

Matt Lacquered

combines the protective benefits of lacquer sealing with the natural look of a treatment with oil.  The colour and texture of the wood are emphasized, whilst it retains its natural matt radiance.  The lacquer finish is fully closed, but the fine wood grain is retained


movement is the swelling or shrinkage when wood is exposed to various humidity conditions


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

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 the exact quantity is applied, ensuring a perfect bond


a preparation for finishing wood floors.  There are many different types of oil on the market.  It is important to know the requirements of the floor and recommended maintenance procedure


the finish penetrates the wood fibers to harden them while not altering the natural beauty of the wood. With no visual film on the surface, oiled floors are distinguishable by their elegant patina. They are easy to care for and are repairable. An oiled floor never needs to be sanded, only regular applications of a Maintenance Oil are necessary to nourish the wood and bring back the luster

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 sub-floors, but today they can be laid over solid sub-floors 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, e.g. Versailles

Random Length

boards which vary in length within one floor

Scotia / Quadrant

a beading used to cover required expansion gap


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’ tongues 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.  There are companies who pump similar materials onto floors and this procedure will form a level base


the surface onto which the decorative wood flooring is laid

Sustainable Source

a source of wood flooring where new trees are continuously planted to replace those cut down

Tongue & Groove

a method of joining individual pieces of wood together.  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”


a material placed under a floor to smooth the sub-floor (e.g. ply), to protect against damp (e.g. polythene) or as a resilient layer under floating floors.  Can also help cut down airborne noise

Wear Layer

the layer of wood nearest the surface in a multi-layered board which receives the foot traffic.  Wear layers are normally quoted on a “nominal” thickness basis – this means the thickness before sanding