Materials and building methods

41 terms in materials and building methods

Slab on ground

A slab on ground is a concrete floor cast directly on the prepared ground, the most common footing and floor system for single-storey homes on suitable sites. Its design, including the depth and reinforcement of its edge and internal beams, follows the site classification, so a reactive site drives a more substantial slab. General information, not engineering advice. See also: Waffle pod slab.

Waffle pod slab

A waffle pod slab is a slab on ground cast over a grid of void formers, usually polystyrene pods, so the concrete forms a waffle of beams above the ground rather than trenched into it. It is a common residential system whose suitability depends on the site classification and preparation. General information, not engineering advice. See also: Slab on ground.

Raft slab

A raft slab is a stiffened slab on ground with integral edge and internal beams that spread the load and resist the movement of a reactive site as a single raft. It is one of the standard footing systems for reactive sites, with the beam depths set by the site classification and the engineer. General information, not engineering advice. See also: Site classification.

Strip footing

A strip footing is a continuous concrete footing that runs beneath a load-bearing wall to spread its load into the ground. It is a traditional footing used under masonry walls and for subfloor construction, sized for the load and the ground it bears on. General information, not engineering advice. See also: Pad footing.

Pad footing

A pad footing is an isolated concrete footing that carries a concentrated load from a column or post into the ground. Pads are used under posts, piers and framed structures, sized to the load and the bearing capacity of the soil. General information, not engineering advice. See also: Strip footing.

Bored pier

A bored pier is a concrete column cast in a drilled hole to carry a building’s load down to stronger ground below the surface. Piers are used where the surface soil is unsuitable or highly reactive, founding the structure on deeper, more stable material. General information, not engineering advice. See also: Screw pile.

Screw pile

A screw pile is a steel shaft with a helical plate that is screwed into the ground to carry a building’s load to a firmer stratum, installed with equipment rather than concrete curing. It is used for difficult ground and offers a fast, low-disturbance alternative to bored piers where suitable. General information, not engineering advice. See also: Bored pier.

Suspended slab

A suspended slab is a concrete floor that spans between supports rather than bearing on the ground, used for upper floors and for ground floors on sloping or poor sites. It is designed to carry its loads across the span, and the system chosen affects both cost and program. General information, not engineering advice. See also: Subfloor ventilation.

Stumps

Stumps are the posts, timber, concrete or steel, that support a suspended timber floor above the ground in stumped construction, common in parts of Victoria and Queensland. Replacing deteriorated stumps to relevel an older home is known as restumping or reblocking. General information, not engineering advice. See also: Bearers and joists.

Bearers and joists

Bearers and joists are the horizontal members of a suspended timber floor, the bearers carried on stumps or piers and the joists spanning across them to support the flooring. Their sizes and spacings are set for the span and load, and together they form the subfloor framing. See also: Stumps.

Reinforcement

Reinforcement is the steel, in bar or mesh form, cast into concrete to give it the tensile strength concrete lacks on its own. The size, placement and cover of the reinforcement follow the engineering design, and getting them right is a hold point because they disappear the moment the concrete is poured. General information, not engineering advice. See also: Formwork.

Formwork

Formwork is the temporary mould that holds wet concrete in shape until it cures, then is stripped away. Its accuracy sets the finished dimensions and level of the concrete, and it must be strong enough to hold the pour without moving, which is why it is checked before the pour goes ahead. See also: Reinforcement.

Concrete slump

Slump is a measure of the wetness and workability of fresh concrete, taken on site before it is placed. Ordering and checking the specified slump matters because concrete that is too wet can lose strength and too stiff can be hard to place and compact. General information, not engineering advice. See also: Control joint.

Control joint

A control joint is a planned line of weakness in concrete or masonry that encourages any cracking from shrinkage or movement to occur along the joint rather than randomly across the surface. Placing control joints is part of detailing concrete and masonry so movement is directed rather than left to chance. See also: Articulation joint.

Timber frame

A timber frame is a structural framework of timber wall frames and roof members that carries the loads of a home, the most common frame type in Australian housing. Frames are commonly prefabricated to the design and delivered for erection, and their accuracy governs everything fixed to them afterwards. See also: Steel frame.

Steel frame

A steel frame is a structural framework of light-gauge steel used as an alternative to timber for wall frames and roof trusses. It offers dimensional stability and termite resistance, and it needs its own detailing, for example around thermal bridging and fixing, which is designed for rather than assumed. See also: Timber frame.

Wall frame

A wall frame is the framed skeleton of a wall, made up of vertical studs between top and bottom plates, with noggins, lintels over openings and bracing. It carries the loads above and provides the fixing for linings and cladding, and it is set out from the plans so openings and services land where they should. See also: Lintel.

Roof truss

A roof truss is a prefabricated triangulated frame that forms the structure of a roof, engineered to span between supports and carry the roof loads. Trusses are made to order from the design and are a common long-lead item, so they are ordered off the programme well before they are needed. See also: Rafter.

Lintel

A lintel is the structural member that spans over a door or window opening to carry the load above it. Its material and size are set for the span and the load, and a lintel that is missing or undersized shows up as cracking or sag over the opening. General information, not engineering advice. See also: Wall frame.

Brick veneer

Brick veneer is a construction where a single outer leaf of brickwork is tied to a load-bearing timber or steel frame behind it, with a cavity between. The frame carries the structure and the brick is the weather skin and finish, which is the common alternative to double brick in Australian housing. See also: Double brick.

Double brick

Double brick, or cavity brick, is a construction with two leaves of masonry separated by a cavity, both contributing to the structure. It offers mass and durability at higher cost than brick veneer, and the cavity and its ties, flashings and weep holes are what keep water out of the wall. See also: Brick veneer.

Blockwork

Blockwork is walling built from concrete masonry blocks, used for structural walls, retaining walls and feature walls. Blocks can be core-filled and reinforced where the design requires, and the finish, face, rendered or painted, is decided as part of the detailing. See also: Rendered finish.

Weatherboard

Weatherboard is horizontal board cladding, traditionally timber and now also fibre cement, fixed in overlapping courses to shed water. It is a lightweight cladding fixed to the frame, and its performance depends on the sarking, flashings and paint or coating behind and over it. See also: Fibre cement cladding.

Fibre cement cladding

Fibre cement cladding is sheet or board cladding made from cement reinforced with fibres, used as a lightweight external finish in sheet, weatherboard and plank forms. It is durable and non-combustible, and cutting it releases silica dust, so it is worked with the required dust controls. General information, not safety advice. See also: Weatherboard.

Autoclaved aerated concrete(AAC)

Autoclaved aerated concrete is a lightweight precast concrete containing fine air bubbles, used as panels or blocks for walls and flooring and known in Australia by the Hebel brand. It is light, workable and offers useful thermal and fire properties, and it is fixed and finished to its manufacturer’s system. See also: Blockwork.

Rendered finish

A rendered finish is a coating applied over masonry or a lightweight substrate to give a smooth or textured external surface. Render can go over brick, block or fibre cement, and the system, substrate, render and coating, is matched so it bonds and does not crack or debond over time. See also: Blockwork.

Roof tiles

Roof tiles are individual concrete or terracotta units laid in overlapping courses on battens to form a pitched roof covering. They give mass and a traditional appearance, need a minimum pitch to shed water, and rely on their flashings, sarking and pointing to keep the roof watertight. See also: Metal roofing.

Metal roofing

Metal roofing is sheet roofing, commonly profiled steel and widely known by the Colorbond brand, fixed over battens or purlins. It suits lower pitches than tiles, is lighter, and depends on correct fixing, flashing and fall to perform, with the sheets often a made-to-measure order. See also: Roof tiles.

Pitched roof

A pitched roof is a roof with sloping surfaces that shed water to the gutters, the common roof form in Australian housing. Its shape is described by terms such as hip, gable, ridge and valley, and the pitch has to suit the covering, because tiles and sheet metal each need a minimum slope to stay watertight. See also: Skillion roof.

Skillion roof

A skillion roof is a single sloping plane rather than the two or more planes of a traditional pitched roof, common in contemporary and low-cost designs. Its low pitch usually calls for sheet metal roofing, and its simplicity in framing is one reason it appears so often on modern homes. See also: Pitched roof.

Eaves and fascia

The eave is the part of the roof that overhangs the wall, and the fascia is the board along its edge that the gutter fixes to. Eaves shade windows and protect walls from rain, so trimming them to save cost has consequences for both weathering and thermal performance. See also: Gutter and downpipe.

Gutter and downpipe

Gutters collect the water running off the roof and downpipes carry it down to the stormwater system. Their size and number are set for the roof area and rainfall, and undersized or poorly fallen gutters overflow into the eaves and walls, which is why they are part of the roof design rather than an afterthought. See also: Flashing.

Flashing

Flashing is the sheet material used to seal and weatherproof the junctions of a roof or wall, such as where a roof meets a wall, a chimney or a penetration. Most roof leaks happen at junctions rather than in the middle of a sheet, which is why flashing detail is where waterproofing is won or lost. See also: Metal roofing.

Batten and purlin

Battens and purlins are the members fixed across the rafters or trusses that the roof covering fixes to, battens generally the lighter members under tiles or sheet and purlins the heavier members in some roofs. Their spacing suits the covering, and the roof covering fixes to them rather than directly to the trusses. See also: Rafter.

Rafter

A rafter is a sloping structural member that runs from the ridge down to the wall, forming the frame of a pitched roof in conventional cut construction. Rafters do the job trusses do in prefabricated roofs, and the choice between them affects both the roof space and the program. See also: Roof truss.

Glazing

Glazing is the glass in a building’s windows and doors, single or double, and a major influence on comfort, energy performance and cost. The energy provisions set performance requirements glazing must help meet, so the glass and frame are selected for their thermal performance, not just their look. General information, not compliance advice. See also: Insulated glazing unit.

Insulated glazing unit(IGU)

An insulated glazing unit is a sealed assembly of two or more panes of glass separated by a spacer and a gas or air gap, commonly called double glazing. It improves the thermal performance of a window over single glazing, and a low-emissivity coating can improve it further, which is why IGUs feature in meeting energy requirements. General information, not compliance advice. See also: Glazing.

Safety glass

Safety glass is glass treated to reduce the risk of injury if it breaks, either toughened glass that shatters into blunt pieces or laminated glass that holds together on an interlayer. It is required in locations where breakage would be dangerous, such as doors and low windows, to the relevant Australian standard. General information, not compliance advice. See also: Glazing.

Plasterboard

Plasterboard is the sheet lining, a gypsum core faced with paper, used for most internal walls and ceilings, fixed to the frame and set at the joints. Specific grades are used for wet areas, fire separation and acoustic performance, so the right board goes in the right place rather than one board everywhere. See also: Cornice.

Cornice

Cornice is the moulding that finishes the junction between wall and ceiling, covering the joint and giving the room its finished line. Its profile is a design choice, from a simple cove to an ornate moulding, and it is part of the fixing and setting stage of the internal fit-out. See also: Plasterboard.

Screed

A screed is a layer of mortar laid to level a surface or to set the falls on it, most commonly under tiles in wet areas and on balconies so water runs to the drain. The falls formed in the screed are what make the waterproofing work, so it is set out to drain rather than laid flat. See also: Waterproofing.