Glossary

A unit of timber units that have been grouped together for storage, handling, transport, or sale. It's a standard unit used in sawmills, warehouses, and construction supply to manage and move timber efficiently.

A strip of wood or another material that is placed between rows of timber or other wood products in a rack. Rack sticks are placed at right angles to the long axis of the timber to permit air to circulate between the layers. Also referred to as "sticker" or "stripper".

A parabolic arch is an arch in which the intrados (the inner curve) follows the shape of a parabola, typically opening downward and symmetric around its central axis. 

Why use a parabolic arch? It provides excellent structural efficiency, material efficiency, and visual elegance.

Flooring made up of small, matching pieces of timber laid on a substrate in a geometric patterns.

Particle board is an engineered wood product made from wood chips, sawmill shavings, or sawdust (ligno-cellulosic material bonded) that are mixed with a synthetic resin or binder and pressed into flat sheets under heat and pressure.

A party wall is a wall that sits on the boundary between two properties and is used by both as part of the structure of their buildings. Typically found in terrace houses, townhouses, duplexes, or row housing, it can be either part of both buildings (a shared wall), or entirely on one property, but supports or divides both.

A surface change due to age or use, such as the fine oxidation of copper or the weathering of wood.

Peeling is a mechanical process in which a debarked log (called a bolt) is rotated against a stationary knife, shaving off a continuous thin sheet of wood — like unrolling a roll of paper.

Common Applications: Plywood, LVL (Laminated Veneer Lumber), decorative veneers, panel products and formwork boards.

Alternative compliance pathways that demonstrate a building meets the requirements of the National Construction Code (NCC) without strictly following the Deemed-to-Satisfy (DTS) provisions. Performance Solutions allow for flexibility and innovation in design, including the use of timber in complex or non-standard applications. They must be supported by evidence—such as expert judgment, modelling, or testing—to prove they achieve the relevant Performance Requirements of the NCC.

A performance-based approach sets measurable performance criteria (e.g., fire resistance, structural strength, thermal efficiency) and allows flexibility in how those criteria are met, encouraging innovation and alternative solutions.

A change in the properties of wood which can occur during drying when stressing exceeds the elastic limit. Permanent set prevents normal shrinkage of the timber and can lead to more obvious defects such as casehardening and honeycombing. Permanent set is the amount of permanent deformation left in timber after a load is removed, meaning the timber does not return to its original shape or dimension.

The ease with which a fluid flows through a porous material (wood) in response to pressure.

A pier is a column-like support, often made of concrete, masonry, steel, or timber, that bears vertical loads and helps support a structure above it.

PEC is a water-based wood preservative used primarily for heavy-duty timber applications, such as utility poles, railway sleepers, and marine structures. It is a modified form of traditional creosote, designed to improve handling, appearance, and environmental performance.

A pile is a deep foundation element used to carry structural loads from a building or bridge down through weak surface soils to firmer ground or rock layers below.

A pin joint is a movable connection between two structural elements that allows them to rotate relative to each other, while transferring axial forces (tension or compression) and blocking sideways or vertical movement.

The small soft core occurring in the centre of a tree trunk, branch, twig, or log.

Plain-sawn timber (also called flat-sawn timber) is wood that has been sawn tangentially to the growth rings of a log, producing boards where the grain runs in wide, wavy patterns. It’s the most common and cost-effective sawing method used in the timber industry.

An intensively managed stand of trees of either native or introduced species, created by the regular placement of seedlings or seed.

The term plate generally refers to a horizontal structural element, often used in framing, load transfer, or connection roles. Its specific meaning can vary depending on context — particularly in timber construction, steelwork, or general building structures.

Common types: 

• Top Plate - Sits at the top of a timber wall frame; supports roof framing like trusses or rafters
• Bottom Plate (or Sole Plate) - Sits at the base of a wall frame; anchored to the floor or slab
• Wall Plate - Generic term for timber elements that distribute loads across a wall
• Sill Plate - Horizontal member fixed to a foundation, supporting vertical studs

In the timber and construction industry, plumb refers to something being perfectly vertical — that is, aligned with the direction of gravity or a true upright line.

A ply is one of the individual layers of veneer in a panel product like plywood, bonded with adhesive so that adjacent layers are oriented with alternating grain directions for strength and stability.

Plywood is a panel product composed of three or more layers of wood veneer, bonded under heat and pressure with strong adhesives, with each layer's grain direction alternating.

A pocket is a cut-out, slot, or cavity formed in timber, concrete, or masonry to receive another element—such as a beam end, sliding door, bracket, or connection hardware.

A pole is a straight, round timber member, typically derived from small-diameter logs, used in structural or utility applications for support, suspension, or framing.

Polyethylene Glycol (PEG) is a water-soluble polymer that can be absorbed into timber to help control shrinkage and distortion as the wood dries.

A portal frame is a planar structural frame in which lateral loads (like wind or seismic forces) and vertical loads (like roof weight) are resisted and transferred through rigid, moment-resisting connections between rafters (horizontal members) and columns (vertical members).

A post is a vertical timber or structural element that carries and transfers compressive loads from the structure above to the support below.

A post and beam structure is a framing system where vertical posts (columns) support horizontal beams, which in turn support the roof or upper floors. The load is carried through these key structural elements to the foundation.

A predryer is a climate-controlled chamber used to gently remove excess moisture from green (unseasoned) timber before it enters a conventional dry kiln. It helps reduce the moisture content gradually, typically from above fibre saturation point (~25–30%) down to a level more suitable for final kiln drying (around 20–30%).

A preservative is a chemical substance applied to timber to protect it from biological threats such as:

• Fungi (rot and decay)
• Insects (like termites and borers)
• Mould
• Marine borers (in coastal or underwater applications)

They extend the life of timber by making it more resistant to deterioration, especially in outdoor, damp, or ground-contact conditions where untreated wood would decay.

Presurfacing is the initial, light machining of green rough sawn timber to create a more uniform surface, making it easier to inspect, grade, or prepare for final finishing. It is intended to permit drying by a schedule more severe than the prescribed schedule for rough sawn timber, achieving faster drying and fewer drying defects.

Pretreatment - steaming refers to a pre-processing step where timber is exposed to steam (moist heat) before further treatment or processing. It is typically done in a controlled environment like a steaming chamber or kiln. It is often done to fix or enhance colour.

A psychrometric chart or psychrometric table is a graphical tool used in engineering and building design to illustrate the physical and thermal properties of moist air. It helps assess risk of condensation or mould growth in timber or other materials.

The psychrometric chart plots the relationships between several properties of air such as dry bulb temperature, humidity ratio, relative humidity, wet bulb temperature, dew point temperature, enthalpy, specific volume. 

In a mass timber building, a psychrometric chart might be used to:

• Predict moisture accumulation in building envelopes
• Design ventilation systems that maintain healthy humidity levels to protect wood
• Evaluate indoor air comfort in naturally ventilated or passive buildings

A purlin is a horizontal structural member used in roof framing. It runs parallel to the ridge of the roof and supports the roof covering (such as roofing sheets or tiles) by transferring loads to the primary structural elements like rafters or trusses. Purlins usually span at right angles to the slope of the roof

Push-pull racking refers to storage systems designed to handle and organise long, heavy timber products (like beams, planks, or panels) using mechanical or manual force to push in or pull out the items from racks. A method for building racks where alternative boards in alternative layers are kept flush with alternate ends. This gives a checkerboard arrangement at the ends of the rack. It is also called topping & tailing.