Timber & Trade Glossary (A–Z)

• ACQ – Alkaline Copper Quaternary, preservative treatment for timber, less toxic than CCA.
• A-frame – Temporary timber structure shaped like an “A,” often for bracing or support.
• Architrave – Moulded trim around doors or windows to cover joints and gaps.

B

• Back sawn – Timber cut tangential to growth rings, producing a cathedral grain.
• Barge board – External board fixed to gable ends to cover roof timbers.
• Batten – Narrow timber strips used for fixing roofing, cladding or ceilings.
• Bearer – Horizontal support timber that carries joists in decking or flooring.
• Bevel – An angled cut on timber edges, often for neat joins or finishes.
• Bird board – Narrow board fixed at eaves to close gaps and keep out birds and rodents.
• Blackbutt – Durable Australian hardwood, fire-resistant and popular for flooring and decking.
• Blue board– A cement-based fibre-reinforced sheet material commonly used as a substrate for external cladding and internal walls.
• Blue pine – Treated radiata pine, dyed blue, commonly used for termite- and decay-resistant framing.
• Bracing – Diagonal timber or steel that stiffens frames against sideways movement.
• Bullnose – Rounded timber edge, common in decking, stair treads, and trims.
• Bushfire Attack Level (BAL) – A rating to indicate the level of fire a material can withstand.
• Butt joint – Simple joint where two timber ends meet square.

C

• Cantilever – Beam or joist extending past its support to carry overhanging loads.
• CCA Treatment – Copper Chrome Arsenate preservative treatment for timber durability.
• Centres – Spacing between the centre point of framing members (e.g., studs, joists), usually in millimetres.
• Chamfer – 45° bevel cut along an edge to remove sharpness or for detail.
• Chalk line – Tool using chalked string to snap straight lines on surfaces.
• Chipboard – Engineered board made from compressed wood chips and resin.
• Chippy – Trade slang for carpenter.
• Cladding – Timber panels fixed to walls for weather protection and design.
• Cumaru – Dense South American hardwood, very durable for decking and external use.
• Cupping – Curving of board edges upwards or downwards due to uneven moisture.
• Cypress Pine – Australian pine with attractive grain and rich colour, used for external structural support (decks, posts, glulam beams) and interior joinery.

D

• Dado – Lower part of an internal wall, often finished with panelling or moulding.
• Decking – The material used in the construction of decks.
• Defects – Natural or machining flaws in timber (knots, splits, warp).
• Delamination – Separation of timber layers, common in plywood or laminated products.
• Dowel – Cylindrical timber used to join two pieces of wood.
• Dressed All Round (DAR) – Timber machined smooth on all sides.
• Dressed Timber – Timber planed smooth for a clean, finished look.
• Durability Class – Rating system showing timber’s natural resistance to decay.

E

• End Grain – Exposed timber surface cut across growth rings.
• End Matched – Boards with tongue and groove on ends for easier joining.
• Engineered Timber – Manufactured wood products like LVL or plywood for strength and consistency.
• Equilibrium Moisture Content (EMC) – Stable moisture level timber reaches in given conditions.

F

• Face – The visible or best-quality surface of timber.
• Fascia – Board fixed to roof edges to support gutters and cover rafters.
• Fiddleback – Wavy grain pattern prized for decorative finishes.
• Finger Jointed – Short timber pieces joined with interlocking “fingers” and glue for strength.
• Fire Retardant – Treated timber or coating designed to slow fire spread.
• Fixings – Screws, nails, bolts, and connectors that secure timber in place.
• FOHC (Free of Heart Centre) – Timber milled clear of the log’s core to reduce splitting.
• Forest Stewardship Council (FSC) – Certification for sustainably sourced timber.
• Formply – Plywood with a smooth, durable coating used for concrete formwork.

G

• Gable – Triangular wall section at the end of a pitched roof.
• Glue-Laminated Timber (Glulam) – Engineered beams made by bonding timber layers.
• Grade – Quality classification of timber based on strength or appearance.
• Green Timber – Recently cut, unseasoned timber with high moisture content.
• Grey Box – Extremely dense Australian hardwood decking with a fine, even texture and excellent durability.
• Grey Ironbark – One of the hardest, heaviest Australian hardwoods, suited to commercial and industrial decking.

H

• Hand Tools – Non-powered carpentry tools such as saws, chisels and hammers.
• Handrail – Timber or metal rail fixed along stairs, ramps, or balconies.
• Hardboard – Dense fibreboard made from compressed wood fibres.
• Hardwood – Timber from broadleaf trees; dense, strong, and durable.
• Hardwood Classes (H1–H6) – Treatment levels indicating timber’s suitability for various conditions.
• Header – Beam over an opening (door or window) transferring loads to studs.
• Heartwood – Mature inner timber, usually darker and more durable than sapwood.
• Hazard Classes (H1–H6) – Treatment levels indicating timber’s suitability for various conditions.

I

• I-Joist – Engineered joist with an “I” cross-section, strong and lightweight.
• Infill – Material used to fill gaps, such as between fence posts or panels.
• Ironbark – Extremely hard Australian hardwood, ideal for heavy-duty outdoor use.

J

• Janka Hardness – Scale measuring how resistant timber is to denting and wear.
• Jarrah – Western Australian hardwood decking with excellent weather and rot resistance. It is stable and easy to machine.
• Joint – Connection where two timber pieces meet.
• Joist – Horizontal timber supporting flooring or decking boards.
• Joist Hanger – Metal bracket securing joists to supporting beams.

K

• Karri – Durable Australian hardwood used in flooring and construction.
• Kiln-Dried (KD) – Timber dried in a kiln to reduce moisture and movement.

L

• Lattice – Criss-cross timber panels used for screening and fencing.
• Level – Tool or reference point ensuring timber is perfectly horizontal or vertical.
• Lintel – Horizontal beam across openings supporting loads above.
• Load Bearing – Wall, beam, or post designed to carry structural loads.
• LOSP Timber – Light Oil Surface Preservative–treated timber, ideal for exposed framing, trims, cladding, decking substrates.
• Lyctine Susceptible – Timber species prone to lyctine borer attack (mainly sapwood).
• LVL (Laminated Veneer Lumber) – Engineered laminated timber beams, highly stable, termite-resistant, ideal for headers, joists, lintels, offering a cost-effective alternative to steel.

• MDF (Medium Density Fibreboard) – Engineered board from wood fibres and resin.
• Merbau – Popular and durable imported hardwood for decking with rich reddish-brown colour.
• Mill Run – Mixed grade timber supplied directly from the mill.
• Mitre Joint – Angled join between two pieces, usually at 45°.
• Mixed Hardwood – Blend of various hardwood species, often used in framing or landscaping.
• Moisture Content (MC) – Percentage of water in timber affecting stability and performance.
• Mouldings – Decorative timber trims for finishing walls, doors, or windows.

N

• Nailplate – Metal plate with nails pressed into timber joints for connection.
• NCC (National Construction Code) – Australian building regulations and standards.
• Nogging – Short timber pieces bracing studs or joists for strength.
• Nominal Dimension/Size – Stated timber size before machining (actual size is smaller).
• Non-Load Bearing – Partition or wall that doesn’t support structural loads.
• Notch – Cut-out section in timber to fit around another member.

O

• Oregon Timber – A softwood, often referred to as Douglas fir, used in framing and general construction.
• OSB (Oriented Strand Board) – Engineered board made from compressed wood strands.
• Overlay Flooring – Thin timber flooring designed to be installed over a subfloor.

P

• Parquetry – Flooring made from small timber blocks arranged in patterns.
• Particleboard – Engineered sheet from compressed wood particles and resin.
• PEFC (Program for the Endorsement of Forest Certification) – Global timber sustainability certification.
• Pine – Common, versatile softwood used widely in construction.
• Pitch – Angle or slope of a roof.
• Plank – Long, flat piece of timber.
• Plinth – Base timber board protecting walls from damage or moisture.
• Plate (Top, Bottom, Wall Plate) – Horizontal members in wall framing supporting studs.
• Plumb – Perfectly vertical alignment.
• Plywood – Engineered sheets of thin timber veneers glued together.
• Posts – Vertical structural supports in fencing, decking, and pergolas.
• Porous – Timber that readily absorbs moisture.
• Prime – First coat of paint/sealer applied to timber surfaces.

Q

• Quad – Small, quarter-round timber moulding for covering gaps in trims.
• Quartersawn Timber – Timber cut at right angles to growth rings for stability.

R

• Radiata Pine – Widely used softwood, commonly treated for outdoor use.
• Rail – Horizontal timber member in framing, fencing, or balustrades.
• Random Length – Timber supplied in non-uniform lengths from the mill.
• Ridge Beam – Main horizontal beam at the roof peak.
• Riser – Vertical part of a step in a staircase.
• Roof Truss – Prefabricated triangular frame supporting the roof structure.
• Rough-Sawn Timber – Timber left unplaned, with a coarse, rustic finish.

S

• Sapwood – Outer, lighter timber in a log; less durable than heartwood.
• Scribe – Shaped cut to match irregular surfaces for a neat fit.
• Seasoned Timber – Timber dried for stability, reduced shrinkage, and strength.
• Secret Nailing – Fixing method where nails are hidden within joints.
• Select Grade – High-quality, visually appealing timber grade.
• Setback – Required distance between a building and property boundary.
• Silvertop Ash – Moderately durable, character-rich Australian hardwood that is prone to checking if not correctly handled.
• Skirting – Decorative product used for internal trim and detailing to cover gaps and joins.
• Softwood – Timber from coniferous trees, generally lighter and easier to work.
• Span – Distance a beam or joist can cover between supports.
• Span Table – Guide showing safe spans for structural timber sizes.
• Spotted Gum – Durable Australian hardwood with low tannin content. It offers an attractive fiddleback grain.
• Square – Tool ensuring right angles in cuts and layouts.
• Stud – Vertical framing member in walls.
• Structural Timber – Timber graded and used for load-bearing applications.
• Surface Check – Small crack along timber grain caused by drying.

T

• Tallowwood – Dense and hard coastal Australian hardwood with natural greasiness, high decay resistance, and well-suited to wet environments.
• Tannins – Natural compounds in some hardwoods that cause staining or leaching.
• Taper – Gradual reduction in timber thickness or width.
• Tempered Hardboard – Hardboard treated for higher strength and water resistance.
• Termite Resistant – Timber naturally resistant (e.g., ironbark, spotted gum) or chemically treated to resist termites.
• Timber Frame – Building structure made primarily from timber members.
• Tongue & Groove (T&G) – Interlocking jointing system for flooring and wall panels.
• Trim – Timber used for finishing edges around openings or walls.
• Truss – Engineered triangular frame for supporting roofs or floors.
• Treated Pine – Pine treated with preservatives to resist decay and pests, including H2, H3, H4, and H5 treatment.

U

• Underlay – Material laid under flooring for cushioning, levelling or insulation.
• Uniform Grain – Consistent timber grain pattern valued in furniture and finishes.
• Unseasoned Timber – Freshly cut timber with high moisture, prone to shrinkage.

V

• Veneer – Thin timber slices glued onto surfaces for appearance or strength.
• V-Joint – Tongue and groove profile with a V-shaped groove.
• Void – Empty space within a structure, often under floors or between studs.

W

• Wall Truss – Prefabricated timber wall frame.
• Warping – Distortion in timber caused by uneven drying or moisture changes.
• Water Resistant – Timber or board treated or manufactured to resist moisture.
• Weatherboards – Horizontal timber boards used as external wall cladding.
• Western Red Cedar – Lightweight, stable, and rot-resistant softwood often used in cladding.
• Wind Load – Pressure exerted by wind on structures, affecting timber design.
• Workability – How easily timber can be cut, shaped, or finished.

Z

• Zoning (Building) – Local building regulations affecting timber use in construction.