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Hardwood Floor Glossary

Hardwood Flooring Glossary Denver, CO

Compiled by the National Wood Flooring Association

Denver Colorado-based MacDonald Hardwoods would like to credit the National Wood Flooring Association for this comprehensive glossary of wood flooring terms.

ACRYLIC/WOOD – The generic name for wood-plastic-composites utilizing wood impregnated with acrylic monomers and polymerized within the wood cells by gamma irradiation. Some versions are cured by heat radiation. (In the case of acrylic/wood parquet, a semi-built-in finish is developed.)

AIR-DRIED – Dried by exposure to air in a yard or shed without artificial heat.

ANNUAL GROWTH RING – The layer of wood growth, including spring and summerwood formed on a tree during a single growing season.

BASE SHOE – A molding designed to be attached to base molding to cover expansion space. Similar to quarter round in profile.

BASTARD SAWN – Lumber (primarily hardwoods) in which the annual rings make angles of 30 Degrees to 60 Degrees with the surface of the piece. (Also known as Rift Sawn)

BEVELED EDGE – (See Eased Edge)

BOARD FOOT – A unit of measurement of lumber represented by a board I foot long, 12 inches wide, and 1 inch thick or its cubic equivalent. In practice, the board foot calculation for lumber 1 inch or more in thickness is based on its nominal thickness and width and the actual length. Lumber with a nominal thickness of less than 1 inch is calculated as 1 inch.

BOW – The distortion of lumber in which there is a deviation, in a direction perpendicular to the flat face, from a straight line from end to end of the piece.

BURL – A swirl or twist of the grain of the wood which usually occurs near a knot, but does not contain a knot.

CHECK – A lengthwise separation of the wood that usually extends across the rings of annual growth and commonly results from stress set up in wood during air drying or kiln-drying.

CHIPBOARD – A paperboard used for many purposes that may or may not have specifications for strength, color, or other characteristics. It is normally made from paper stock with a relatively low density in the thickness of 0.006 inch and up.

COMPRESSION SET – Caused when wood strips or parquet slats absorb excess moisture and expand so much that the cells along the edges of adjoining pieces in the floor are crushed. This causes them to loose resiliency and creates cracks when the floor returns to its normal moisture content.

CONIFEROUS – (See Softwoods)

CROOK – The distortion of a board in which there is a deviation, in a direction perpendicular to the edge, from a straight line from end to end of the piece.

CROSSPULL – A condition occurring at an end-joint with the ends of flooring strips pulled in opposite directions.

CROWNING – A “convex” or “crowned” condition or appearance of individual strips, with the center of the strip higher than the edges. (Opposite of cupping.)

CUPPING – A “concave” or “dished” appearance of individual strips, with the edges raised above the center. (Opposite of crowning)

CURE – To change the properties of an adhesive by chemical reaction (which may be condensation, polymerization, or vulcanization) and thereby develop maximum strength. Generally accomplished by the action of heat or a catalyst, with or without pressure.

CUSTOM FLOORS – Wood floors that are made to order. Complete flexibility is allowed for design, species, grade, etc.

DECAY – The decomposition of wood by fungi.
• Advanced Decay – The older stage of decay in which destruction is readily recognized by soft, pitted, or crumbly areas. Decided discoloration or bleaching of the rotted wood is often apparent.
• Incipient Decay – The early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. It is usually accompanied by a slight discoloration or bleaching of the wood.

DELAMINATION – The separation of layers in a laminate, through failure within the adhesive, or at the bond between adhesive and laminate.

DECIDUOUS – (See Hardwoods)

DIFFUSE – POROUS WOODS – Certain Hardwoods in which the pores tend to be uniform in size and distribution throughout each annual ring or which decrease in size slightly and gradually toward the outer border of the annual growth ring. (EXAMPLE: Hard Maple)

DIMENSIONAL STABILITY – The ability to maintain the original intended dimensions when influenced by a foreign substance. Wood is hygroscopic, and is not dimensional stable with changes in moisture content below the fibre saturation point.

DISTRESSED – A heavy artificial texture in which the floor has been scraped, scratched, or gouged to give it a time-worn antique look. (A common method of distressing is wirebrushing.)

DRY WALL – Interior covering material, such as gypsum board, hardboard, or plywood, which is applied in large sheets or panels.

EASED EDGE – The chamfered, or beveled edge, of strip flooring, plank, block, and parquet at approximately a 45 degree angle.

END – JOINT – The place where two pieces of flooring are joined together end to end.

END MATCHED – In strip and plank flooring the ends of individual pieces have a tongue milled on one end and a groove milled on the opposite end, so that when the individual strips or planks are butted together, the tongue of one piece engages the groove of the next piece.
OR (A male projection milled on one edge of a strip, plank, slat or unit to be engaged with a female counterpart on an adjoining unit.)

EOUILIBRIUM MOISTURE CONTENT – The moisture content at which wood neither gains nor loses moisture when surrounded by air at a given relative humidity and temperature.

FEATURE STRIP – A molding accessory for parquet floors utilized to separate squares into patterns larger than the individual parquet units. It is available in widths from 5/16″ to 2″, the same thickness as the parquet, and is available in various lengths. The strip is flat and may have grooves on both sides to match the tongues of adjacent plank or parquet.

FIBERBOARD – A broad generic term inclusive of sheet materials of widely varying densities manufactured of refined or partially refined wood (or other vegetable) fibers. Bonding agents and other materials may be added to increase strength, resistance to moisture, fire, or decay, or to improve some other property.

FIBER SATURATION POINT – The stage in drying or wetting wood at which the cell walls are saturated with water and the cell cavities are free from water. It is usually taken as approximately 30% moisture content, based on ovendry weight.

FIGURE – Inherent markings, designs, or configurations on the surface of the wood produced by the annual growth rings, rays, knots, and deviations from regular grain.

FILLER – In woodworking, any substance used to fill the holes and irregularities in planed or sanded surfaces to decrease the porosity of the surface before applying finish coatings.
Wood Filler – (for Cracks, Knot Holes, Worm Holes, Etc.) Usually a commercial wood putty, Plastic Wood, or other materials mixed to the consistency of putty. A wood filler may also be mixed on the job using sander dust from the final sanding, or other suitable material, mixed with a sealer or finish.

FIRE RESISTANCE – The property of a material or assembly, to withstand fire or give protection from it.

FIRE RETARDANT – A chemical or preparation of chemicals used to reduce flammability or to retard spread of a fire over the surface.

FLAG – A heavy, dark mineral streak shaped like a banner.

FLAG WORM HOLE – One or more worm holes surrounded by a mineral streak.

FLAME SPREAD – The propagation of a flame away from the source of ignition across the surface of a liquid or a solid, or through the volume of a gaseous mixture.

FLECKS – The wide irregular conspicuous figure in Quartersawn oak flooring. (Also, See Rays, Wood)

HARDWOOD – Generally, one of the botanical groups of deciduous trees that have broad leaves in contrast to the conifers or softwoods. The term has no reference to the actual hardness of the wood.

HEARTWOOD – The wood extending from the pith of the sapwood, the cells of which no longer participate in the life processes of the tree. It is usually darker than sapwood.

HEAVY STREAKS – Spots and streaks of sufficient size and density to severely mar the appearance of the wood.

HONEY COMBING – Checks often not visible at the surface, that occur in the interior of a piece of wood, usually along the wood rays.

HYGROSCOPIC – A substance that can absorb and retain moisture, or lose or throw off moisture. Wood and Wood Products are hygroscopic. They expand with absorption of moisture, and dimensions become smaller when moisture is lost or thrown off.

INTUMESCE – To expand with heat to provide a low density film; used in reference to certain fire retardant coatings.

JOINTED FLOORING – Strip flooring, generally Birch, Beech & Hard Maple, or Pecan, manufactured with Square Edges and no tongue or groove, usually endmatched. Used principally for factory floors where the square edges make replacement of strips easier.

JOIST – One of a series of parallel beams used to support floor or ceiling loads and supported in turn by larger beams, girders, or bearing walls.

KILN – (Pronounced “Kill”) A chamber having controlled air flow, temperature, and relative humidity for drying lumber, veneer, and other wood products.

KILN DRIED – Dried in a kiln with the use of artificial heat.

KNOT – That ponion of a branch or limb which has been surrounded by subsequent growth of the stem. The shape of the knot as it appears on a cut surface depends on the angle of the cut relative to the long axis of the knot.
• Small Knot – In hardwood strip flooring not over 1/2″ in diameter.
• Pin Knot – A knot that is not more than 1/2 inch in diameter.
• Sound Knot – A knot cut approximately parallel to its long axis so that the exposed section is definitely elongated.

LAMINATED WOOD – An assembly made by bonding layers of veneer or lumber with an adhesive. May also refer to edge-glued lumber items such as treads, etc.

MANUFACTURING DEFECTS – Includes all defects or blemishes that are produced in manufacturing, such as chipped grain, torn grain, skips in dressing, hit and miss (a series of surfaced areas with skips between them), variation in machining, machine burn, and mis-matching.

MEDULLARY RAYS – Strips of cells extending radially within a tree and varying in height from a few cells in some species to four or more inches in oak. The rays serve primarily to store food and transport it horizontally in the tree. On quartersawn oak, the rays form a conspicuous figure, sometimes referred to as Flecks.

MINERAL STREAK – Wood containing an accumulation of mineral matter introduced by sap flow, causing an un-natural color ranging from greenish brown to black.

MIXED MEDIA – A wood floor that is predominantly of wood but incorporates other materials such as slate, stone, ceramic, marble or metal.

MOISTURE CONTENT – The amount of moisture in wood expressed as a percentage of the weight of the oven dry wood.
NOFMA hardwood flooring is manufactured at 6% to 9% moisture content, with a 5% allowance for pieces up to 12% moisture content.
APA parquet flooring is to be 7% to 11 % moisture content at time of shipment. 5% of the flooring may be outside of this range.

MOSAIC PARQUET – A parquet flooring made up of small solid pieces of wood (slats) assembled in units that may consist of individual squares, units with slats arranged in single or double herringbone design units or squares bordered with slats of the same or contrasting species.

NOSING – A hardwood molding used to cover the outside corner of a step, milled to meet the hardwood floor in the horizontal plane, to meet the riser in the vertical plane. (Usually used on landings.)

NOMINAL SIZE – As applied to timber or lumber, the size by which it is known and sold in the market; often differs from the actual size.

PARQUET – A patterned floor.

PARQUET FLOOR SQUARE – Basically a “tile” composed of individual slats held in place by a mechanical fastening. A square mayor may not possess tongues and grooves to interlock, and is not necessarily “square” or regular in dimension.

PAROUET FLOOR UNITS – A unit consists of four (sometimes three) or more squares or “tiles” fastened together.

PARTICLEBOARD – A generic term for a material manufactured from wood particles or other ligno-cellulosic material and a synthetic resin or other suitable binder.
Flakeboard – A particle panel product composed of flakes.
Oriented Strand Board – A type of particle panel product composed of strand-type flakes which are purposefully aligned in directions which make a panel stronger, stiffer, and with improved dimensional properties in the alignment directions than a panel with random flake orientation.
Waferboard – A particle panel product made of wafer-type flakes. Usually manufactured to possess equal properties in all directions parallel to the plane of the panel.

PIN WORM HOLE – In hardwood flooring, a small round hole not over 1/16″ in diameter, made by a small wood-boring insect.

PITH – The small, soft core occurring near the center of a tree trunk, branch, twig, or log.

PLAINS A WED – The annual growth rings make an angle of less than 45 Degrees with the surface of the piece. This exposes the pores of the springwood and dense summerwood of the annual growth ring in ring-porous woods to produce a pleasing grain pattern.

PLANER BITE – A groove cut in the surface of the piece deeper than intended by the planer knives.

PLANK – Solid boards, usually 3/4″ thick and 3″ to 8″ wide designed to be installed in parallel rows. Edges may be beveled to simulate the appearance of Colonial American plank floors.

PLUGS – Dowels that simulate the Colonial American plugged or pegged plank look. Sometimes used to cover counter-sunk screws when installing plank.

PREFINISHED – A completely finished flooring that requires installation only.

QUARTERSAWED – The annual growth rings form an angle of 45 Degrees to 90 Degrees with the surface of the piece. In Quartersawed strips the medullary rays or pith rays in ring-porous woods are exposed as flecks which are reflective and produce a distinctive grain pattern.

RAISED GRAIN – A roughened or fuzzy condition on the face of the flooring in which the dense summerwood is raised above the softer springwood, but not torn or separated.

RAYS WOOD – Strips of cells extending radially within a tree and varying in height from a few cells in some species to 4 inches or more in oak. The rays serve primarily to store food and transport it horizontally in the tree. On Quartersawn oak flooring, the rays form a conspicuous figure, sometimes referred to as Flecks.

REDUCER STRIP – A teardrop shaped molding accessory for hardwood flooring, normally used at doorways, but sometimes at fireplaces and as a room divider. It is grooved on one edge and tapered, or feathered, on the other edge. Various lengths are available.

RELATIVE HUMIDITY – Ratio of the amount of water vapor present in the air to that which the air would hold at saturation at the same temperature. It is usually considered on the basis of the weight of the vapor but, for accuracy, should be considered on the basis of vapor pressures.

RIFT SAWN – Lumber (primarily hardwoods) in which the annual rings make angles of 30 Degrees to 60 Degrees with the surface of the piece. (Also known as Bastard Sawn.)

RING POROUS – A group of hardwoods in which the pores are comparatively large at the beginning of each annual growth ring and decrease in size, more or less abruptly, toward the outer portion of the annual growth ring. The large pores are springwood and the smaller pores are summerwood.

SAPWOOD – The wood near the outside of the tree. Usually lighter in color than heartwood.

SAWN – (See Plainsawed, Quartersawed, Bastardsawn)

SCREEDS – Usually a 2″ by 4″ laid flat-side down and attached to a concrete subfloor to provide a nailing surface for tongued and grooved strip flooring or a wood subfloor.

SLEEPER – Another name for SCREEDS.

SHAKE – A separation along the grain, the greater part of which occurs between the annual growth rings.

SHEATHING – The structural covering, usually boards or plywood, placed over the exterior studding or rafters of a structure.

SLATS – The small solid hardwood pieces which form Mosaic Parquet Squares.

SLIP-TONGUE – A spline or small strip of wood or metal used to reverse or change direction in installing standard tongue and groove strip flooring. Sometimes used in laying 3/4″ solid Tongue & Groove parquet.

SOFTWOOD – General term used to describe lumber produced from needle and/or cone bearing trees (Conifers).

SPLIT – Separations of wood fiber running parallel to the grain.

SQUARES – Usually composed of an equal number of Slats.

SQUARE EDGE – A flooring that is NOT Tongue & Grooved. Square-edged strip flooring is face nailed when installed. (Also See Jointed Flooring.)

SQUARE JOINT – Tongue & Grooved strip or plank flooring with edges that are not eased or beveled.

STAIN – A discoloration occurring in or on flooring of any color other than the natural color of the species. For instance, blue stain, brown stain.

STREAKS – (See Mineral Streaks)

STRIP FLOORING – Solid boards to be installed in parallel rows now produced in the thicknesses 1/2″, 3/4″, 33/32″ and the widths 1-1/2″, 2″, 2-1/4″, and occasionally 3-1/4″. The strips are Tongue & Grooved and end-matched. They are for nail down installation directly to wood or plywood subfloors, or over wood screeds on concrete slab construction.

STUD – One of a series of slender wood structural members used as supporting elements in walls and partitions.

TONGUE & GROOVE (T&G) – In suip, plank, and parquet flooring made from strip, and some mosaic parquet; a tongue is milled on one edge and a groove on the opposite edge. As the flooring is installed, the tongue of each strip, slat, or unit is engaged with the groove of the adjacent strip or unit.

TRIM – The finish materials in a building, such as moldings, applied around openings (window trim, door trim) or at the floor and ceiling of rooms (baseboard, shoemold, cornice, and other moldings).

UNFINISHED – A product which must be sanded and have stain and/or a finish applied after installation.

UNITS – Four or more basic Mosaic Parquet Squares; or four or more slats in 3/4″ parquet, usually made from T&G strip flooring combined into a parquet unit.

V-JOINT – A term used in plank flooring to indicate that edges are eased or beveled to simulate cracks in floors of early Colonial American homes.

VAPOR BARRIER – A material with a high resistance to vapor movement such as foil, plastic film, or specially coated paper, that is used to control condensation or prevent migration of moisture.

WARPING – Any distortion of a piece of flooring from its true plane that may occur in seasoning.

WIRE BRUSHING – A method for imparting an artificial texture or distressed appearance to the surface of hardwood flooring.

Contact MacDonald Hardwoods for more information at 800-639-3006.