Glossary

A list of terms used in the oak flooring industry

Acclimatisation - Linked to the moisture content of solid oak flooring, acclimatisation is the process of matching the moisture content of the wood to the humidity of the room where the floor boards will be laid. The longer the floor boards can be left to acclimatise before fitting the better. We recommend at least 4 to 6 weeks for solid oak floor boards. If your space is going to be heated, try to run the heating at normal levels for the entire time the oak is acclimatising. If you are installing an oak floor in a room which has been newly plastered and is unheated, you should be absolutely sure the room is at normal humidity levels before you introduce the floor boards for acclimatisation.

Check - A crack along and across the grain usually caused by drying.

Crowning - The opposite of cupping, a condition where a floor board's edges are lower than its centre giving a convex appearance across the board.

Cupping - The opposite of crowning, a condition where the centre of a board is lower its edges giving a concave appearance across the board.

End matched - Refers to floor boards where a tongue is cut into one end of the board and a groove in the other end. This allows for a perfect join between two boards when placed end to end.

Figuring - The general term given to the patterns formed by wood grain. These often beautiful patterns occur as the result of stress during the tree's life or burrs and bulges on the trunk.

Growth ring - Each year, a tree grows a new layer of sapwood which manifests itself as a growth ring. The growth rings form the grain of the floor boards.

Hardwood - The wood from broad-leaved deciduous trees such as oak. Hardwood does not refer to the "hardness" of the wood - balsa is also a hardwood and yet is possibly the "softest" wood in existence.

Heartwood - Wood from the, often dead, central growth rings of the tree. This wood is usually darker than the sapwood.

Hearting - The term given to the beautiful grain patterns formed when heartwood is made into flooring and a feature of quarter-sawn boards.

Hygrometer - A tool for measuring the moisture content of wood. The hygrometer has two metal pin-like probes which are pressed into the wood. An electrical current is passed between the probes with the strength of the current dependent upon the moisture in the wood. This gives a moisture reading expressed as a percentage.

Kiln-dried - Oak flooring which has been heated in a kiln, essentially a large oven, to dry it down to a predetermined moisture content.

Knots - The circular, usually dark, and sometimes loose markings found in sawn timber. A knot is a section of branch which was attached to the main trunk or larger branch. Often, the lower branches of a tree will die as it grows but remain attached. The tree trunk continues to grow around the dead branch and once the tree is felled and sawn, the dead branches appear as knots.

Micro-bevel - The slight chamfer or angled cut applied to the top edges of some solid oak floor boards. When two boards are fitted together, the micro-bevels form a small groove between the boards which helps to give definition across the whole floor.

Moisture content - Most of the boards we supply have been kiln-dried to between 12% and 14% moisture when measured with a hygrometer. For applications where oak floor boards will be laid over heating pipes or underfloor heating, boards must be kiln-dried further down to around 8% moisture to avoid shrinking and cracking.

Parquet - Any floor where strips of wood are laid to create a geometric or coloured pattern.

Pinhole - A tiny hole in a floor board, caused by an insect, disease or genetic defect.

Plainsawn - Where the growth rings of the wood are cut at less than 45 degrees to the surface of the board. This gives the long, flowing grain as seen in our barn grade, character grade and select grade solid oak flooring.

Pre-finished - Floor boards which have been sanded, dyed and waxed ready for laying and requiring no further treatment.

Quartersawn - Where the growth rings of the wood are cut at between 45 and 90 degrees to the surface of the board. This gives a shorter, tighter looking grain with beautiful figuring. Quarter sawn oak boards are considerably more expensive than plainsawn as there is more labour and more waste in their production.

Sapwood - Wood from the outer growth rings of a tree which is usually lighter in colour than the heartwood.

Shake - A crack which opens up between two growth rings running along the grain.

Tongue and Groove - Floor boards which have one edge machined to form a protruding "tongue" and the opposite edge machined to form a groove. When two boards are joined side by side, the tongue from one board lots into the groove on the other.

Unfinished - Floor boards in their natural state which need to be sanded, stained and waxed before or after laying.