Glossary of basic construction terms


Coarse material such as crushed stone, gravel, sand etc used to mix into concrete, laying beneath paving or foundations. 



Frame around a door or window. 


Refilling a hole in the ground with material that was previously dug out of it. For example: after stormwater drains are laid into trenches, previously excavated soil is placed on top of the pipes as backfill.


A railing (consisting of horizontal handrail and vertical balusters), for example surrounding a balcony or stairs.

Barge board

Wide board (usually timber) attached to ends of roofing elements to protect and conceal them from weather and view.


Horizontal structural element.

Brick veneer

Layer of bricks on the outside of the building which is for cladding purpose only - it does not support the weight of the building. (Most New Zealand houses with brick on the outside are brick veneer - the inside is held up by timber framing.)

CAD (computer-aided design)

Computer software used by architects, engineers and others to create precision drawings or technical illustrations.

Cavity (wall)

Gap left intentionally between exterior cladding (such as brick) and interior (such as timber framing) to reduce the amount of moisture moving from outside of the building to the inside.


Layer of material protecting elements beneath it, for example, corrugated iron sheets are cladding on roofs, bricks are cladding on walls.


Vertical structural element.


When company who provides design services is the same that will construct the building.

Dwangs (a.k.a nogs or blocking)

Horizontal pieces of timber framing used between vertical studs to provide the wall with rigidity.


Edges of roof overhanging the face of a wall.


Synonym for facade, side view of the building, as opposed to "plan" which is top view. "North elevation" therefore means "view of the building from the north". 

Expansion joint

Line of separation between two adjoining elements that provides with space to move in response to temperature, earthquake, wind etc without damaging the material itself. Very common in concrete.


Board (usually timber) attached to bottom of roof rafters - it provides a flat surface onto which drains for stormwater (ie spouting) can be attached.


Lower part of the building - it transfers the weight of the building onto ground below. Most commonly concrete slab or timber piles.


Mould into which concrete is poured.


Fitting together of pieces to give structure support and shape. Most commonly timber, but can also be steel.


Triangular part of wall at the end of (or under) a ridged roof.


Short for heating, ventilation & air conditioning.


Material that prevents heat (or sound, or electricity - depending on function) spreading from one building element onto another.


Building elements constructed by a joiner (rather than a carpenter/builder) such as cabinetry, doors, built-in shelving etc.


Horizontal element supporting floor or ceiling (usually made of timber or steel).

Load-bearing wall

Wall that supports the weight of other building elements above it and, therefore, cannot be removed without putting other support mechanisms in place (otherwise it would risk the collapse of building above it).


Stonework such as bricklaying.

Moisture barrier (a.k.a vapour barrier)

Material used to prevent moisture moving from one building element to another. For example: polythene sheet under concrete, or bitumen on roof.

Penetrometer testing

Method used to test ground conditions by dropping a specific weight onto it. (In soft soil, the weight penetrates the ground much easier than in hard ground.)


Type of foundation where series of long posts (timber, steel or concrete) are dug into the ground to support the weight of the building. (Random fact: Venice in Italy is built almost entirely on piles.)


Other word for (large) tools, equipment and machinery.


Board (commonly used on walls and ceilings) that is made of plaster and covered on both sides with heavy paper. Usually painted afterwards.


Board made of thin sheets of timber glued together. Each layer is called "ply": a 9-layer plywood is a "9-ply". Commonly used on walls, ceilings and beneath floors.

Precast concrete

Concrete (usually wall panel or floor) that's manufactured entirely in a factory and then transported to building site to lift in place (rather than pouring it on the building site itself).


A horizontal beam along the length of a roof, either below rafters (underpurlin) or on top of them.


Short for polyvinyl chloride - a type of plastic commonly used for pipes and windows.


Main support structure holding up a roof and giving it a common triangular shape.


Steel embedded inside concrete to give it strength, usually in the shape of rods, bars and mesh.


Timber panels attached to roof surface, so that roofing tiles can be nailed directly onto it. Can also mean waterproof building material under roof tiles; or a 19th century construction technique of attaching timber panels inside wall and ceilings, so that wall coverings had a flat surface to attach to.


Temporary structure on the outside of a building, made of wooden planks and metal poles, used by workmen while building, repairing or cleaning the building.


Other word for plumbing, electrical, heating etc - systems used to make a building comfortable, functional and safe.


Moulding in the bottom of a wall to cover the joint between floor and wall.


Under-surface of something: most commonly, soffit is used to refer to underside of roof eaves.


Filling of small blemishes (scratches, nail holes, gaps) in a surface that's about to be painted, for example plasterboard.


Vertical member in wall framing, between floor and ceiling.


Other word for measurement - counting and measuring of construction elements (floor area, doors, timber framing etc) from architectural plans so an accurate estimate can be put togethe.


In construction, truss is a common word for a partially pre-fabricated roof structure which can be assembled on site (rather than building the entire roof on site).


Small opening left in brickwork to allow moisture to drain out and ventilation to get in behind bricks.

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