Commercial building jargon

COmmercial Building glossary

We’ve put together the most commonly used terms in the commercial building industry to help you have the best understanding when working on your next building project.


The highest point or tip of a building. Usually the ridgeline.

Apex braces

A horizontal member for bracing the angle between the two rafters where they join at the apex.

Due to the structural strength of the XL portals, no obtrusive knee or apex braces are usually required. This ensures a clean look and maximises internal clearance.

Bay size

The centre to centre distance between portal frames.


Bracing is used to increase the rigidity and structural performance of a building.

Typical bracing includes:

  • Reid or RB Bracing
    • ReidBrace™ is an off-the-shelf system that provides a solution for the tension bracing of structures. ReidBrace™ utilises ReidBar™, a continuously threaded reinforcing bar system, as tension members. 
  • Metal Strap bracing
  • Structural steel bracing
Chemset bolts

Chemset bolts are a type of chemical anchor. Chemical anchors are steel bolts that are bonded into holes drilled in the concrete using a resin-based adhesive.


Cladding is the material that covers the external walls and roof. Industrial buildings often use profiled coloursteel cladding but can include precast concrete for durability and fire rating, other claddings such as aluminium panel cladding, titan board, and glass curtain walls can be used to up-spec the ascetics.

Cladding, Coloursteel

Coloursteel is a common name used for profiled steel cladding in a coloured finish. It is a cost-effective and durable cladding solution for industrial and agricultural buildings.

COLORSTEEL® is a brand of profiled metal cladding that is commonly used throughout New Zealand.

Cladding, Zincalume

ZINCALUME® is a New Zealand Steel brand of profiled metal cladding. It is a Zinc/aluminium alloy coated steel. The ZINCALUME® steel coating combines the corrosion protection of aluminium with the sacrificial protection of zinc to create an alloy that's ideal for roofing and cladding in New Zealand's demanding environment.

Zincalume has a metallic finish and is used as a cost-effective cladding solution when a specific colour is not required.

Clear span

The clear distance that a rafter extends between columns without support columns between.


CLT stands for cross-laminated timber. It is a wood panel product made from glueing together layers of solid timber together. Each layer of boards is usually oriented perpendicular to adjacent layers. (Similar to plywood but with thicker laminations). CLT can be used in numerous structural applications including Midfloor construction for double level offices.


A column is the vertical structural member which makes up the portal frame also referred to as the leg.

Connections / Joints

As it sounds, this is where structural members are joined/connected.

The XL system uses simple bolted connections for the knee and apex joints. This gives you connections that are much stronger than using Tek screws and pressed steel brackets.

Due to the structural strength of the portals, usually, no obtrusive knee or apex braces are required. This ensures a clean look and maximises internal clearance.

Consultants, Accessibility consultant

A specialist consultant who is trained to provide practical advice to overcome disability access issues and advise regarding compliance requirements for accessibility.

Consultants, Acoustic engineer

Acoustics engineers can provide prediction, assessment, measurement, and management of noise. They provide advice on legislative aspects of the building code, district plan/resource consent requirements around noise and vibrations.

Consultants, Architectural designer

An architectural designer plans and designs the layouts for buildings and sites. They interact with clients to gather design requirements, specifications, and budgets for their building projects.

Consultants, Civil engineer

A civil engineer designs and oversees aspects such as stormwater management, sewage, and industrial waste management, retaining walls, roads, and hardstand design such as concrete yards and car parks.

Consultants, Fire engineer

Fire engineers plan and design safety features that detect, control or reduce fire and smoke in buildings and structures. They also analyse how fire behaves and how safety features perform in a fire. A fire engineer is a qualified professional that can provide both acceptable solutions fire reports and verified method fire reports to accompany building consent documentation. A fire design consultant is not as qualified as a fire engineer but can provide acceptable solution fire reports in accordance with the New Zealand building code.

Consultants, Geotech engineer

A geotechnical engineer analyses, plans, and monitors the construction of foundations and deals with rock, soil, and any part of the building structure that is placed underground. The principal objective of the geotechnical engineer is the protection of life and property against damage caused by various geological conditions by careful design of underground or ground supporting structures.

Consultants, Structural engineer

A structural engineer works alongside architectural designers and geotech engineers and focuses on the strength of the framework of structures. They design those structures to withstand the stresses and pressures of their environment to remain safe, stable and secure throughout their use. They provide calculations and producer statements to accompany the building consent documentation.

Doors, Roller door

A roller door consists of a single piece of curtain and is of lighter construction than a roller shutter door. Roller doors are often faster to open than a roller shutter door but they do not offer as large opening sizes as a roller shutter door.

Doors, Roller shutter door

A roller shutter door consists of many horizontal slats hinged together to create a heavy-duty door for industrial uses. Roller shutter doors provide a stronger construction than roller doors. They provide greater security and offer larger opening sizes.

Doors, Sectional door

Sectional doors are made of separate panels connected by hinges that lift upwards. Castors are fixed to the panel edges allowing the door to move up and down a curved track system. The door would usually sit parallel to the ceiling when open. They are commonly used in residential applications and are also used in commercial applications where there is limited headroom.


Fastbrace is a lock-in bracing system that is used in conjunction with c-section purlins. Fastbrace runs in continuous lines between purlins/girts to provide resistance to restrict lateral movement of the purlin system.


Flashing is typically a thin sheet metal component, folded in a way to direct the moisture to the outside of cladding.

Flashings, Barge flashing

Barge flashings are the flashings used at the ends of a roof to provide closure between roof cladding sheets and walls. They provide protection against high winds and ensure a professional and neat finish to any building.

Flashings, Closure flashing

Closure flashing is a folded metal flashing around the base of the wall cladding to allow moisture to escape while closing off gaps at the base of the cladding to help stop vermin from being able to get into the building.


Footings are part of the foundation typically made of a shallow concrete pad with reinforced steel bars. The footings sit below each steel column.


Foundation is the structure that transfers the loads from the building to the ground. Foundations for structural steel buildings are typically made with augured or pad footings, however, some ground types may require additional piling or tying of the concrete floor slab into the footings to form part of the foundation.

Gantry, Gantry corbel

A corbel is a structural steel member jutting from a column to carry the weight of the gantry crane.

Gantry, Gantry downshop solid section rail

The downshop solid section rail is the track supported by the runway beams, on which the gantry crane travels. They are also known as runway rails.

Gantry, Gantry runway beam

The runway beams are structural members on which the gantry crane travels.


A girt is a horizontal structural member in a framed wall. Girts provide lateral support to the wall panel, primarily to resist wind loads.

Girts are typically bolted between the portal legs, rather than bolted to the outside. This gives a cleaner design and more usable space in the building.


Glulam stand for glued laminated timber. Glulam is made from thicker sections of timber, generally 15-45mm thick, glued together to form a large variety of products such as beams, posts and rafters.

Hold-down bolts

Hold-down bolts are steel bolts usually fixed into the concrete foundations with their threaded portion projecting. They are used to secure the columns to the foundations. These are typically located within the footings prior to the concrete being poured.


Joists are the horizontal members used to create a floor skeleton. Joist can be thought of as several small beams that may rest on top of beams or be fastened to the sides of beams. A joist transfers load from flooring to structural beams or frames.


In construction, the knee is the point the column or legs join the rafter.

Knee brace

A diagonal member for bracing the angle between a column and rafter.

Knee height

The distance from the ground floor to the underside of roof cladding on the exterior wall.


LVL stands for laminated veneer lumber. It is an engineered wood product and is typically used as structural members for lintels, beams, mid-floors, and roofs across residential and commercial building projects.


A mezzanine is, strictly speaking, an intermediate floor in a building that is partly open to the double-height area of the floor below, or which does not extend over the whole floor space of the building.

Mezzanine beam

A mezzanine beam is a horizontal member spanning an area and carrying the load of the intermediate floor structure. A beam transfers the load to the vertical columns or frames.

Portals / Portal frames

Portal frames are the structural frame where the vertical columns are connected to the rafter with fixed joints. The joints between the rafters and columns are rigid.


A purlin is a horizontal framing member, usually spanning between rafters or portals, and provides support for the roof cladding.

Types of purlins include:

  • Steel Bone Purlin. This is an enclosed steel purlin that is birdproof, vermin proof and has no visible roof and wall fixings.
  • C section purlins
  • Boxed purlins
  • Timber
  • Structural steel purlins


Purlins, Nested purlins

Purlins are nested between the rafters to optimum clearance and a clean smart look. It also removes places for birds to perch on the rafters and nest.

Purlins, Purlin blocking

A purlin block is a member placed between purlins to help spread load evenly from the roof cladding across all purlins and reduces purlin roll.


A rafter is one of a series of sloped structural members that extend from the ridge to the external wall and form part of the internal framework of a roof.


Structural steel in a Rectangular Hollow Section shape. Not to be confused with a roll-formed beam in a rectangular shape.

RHS (rectangular hollow section) Portals. The XL portal system uses RHS structural steel sections. Depending on the span, these can be 300 - 600 deep and have a wall thickness of up to 12.5mm. Using these sections, clear-spans of 50m+ can be achieved.

Roll-formed beam

A Roll-formed beam refers to a beam that is produced from a thin, lightweight steel plate. The strength of the member is created from its shape. Roll-Formed members can lose their structural strength if dented or deformed.

Roof pitch

Roof pitch is the angle of the roof. This is usually measured in degrees.

Roof ridge

The ridge of a roof is the peak where two opposing roof planes meet.


The distance measured between the two sides of the building typically measured the same direction as the rafter.

Universal beam / I beam / RSJ

A structural steel beam that has a cross-section resembling the capital letter 'I'. Also known as a universal beam (UB) or rolled steel joist (RSJ).

Universal column / H beam

A universal column (UC) is similar to an I beam however the flanges are as wide as the beam height to form an 'H' shape hence it is also called an H beam.

Waler beam

A structural waler beam is a horizontal beam attached with bolts to an upright column/leg. Waler beams are often used when walls are constructed from precast concrete. A waler beam is used to support brace and support the columns and connect the precast concrete walls to the building structure.

Wind column

An intermediate column that supports the rafter between the two exterior legs.