CPC31020 Solid Plastering flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hierarchy of control

A ranked order for managing risk: eliminate the hazard first, then substitute, isolate, use engineering controls, apply administrative controls, and use personal protective equipment last.

Respirable crystalline silica

Fine dust particles from cutting, sanding or mixing plaster that can reach the deep lung. Controls include wet methods, on-tool extraction and fit-tested respiratory protection.

Safety data sheet sections

A safety data sheet has sixteen sections, covering identification, hazards, composition, first aid, firefighting, accidental release, handling, exposure controls, physical properties, stability, toxicology, ecology and disposal.

Scaffold working platform

A platform at least 450 millimetres wide, fully decked, with guardrails, mid-rails and toe boards, and planks secured so they cannot move or tip.

Washout containment

A lined or bunded area where plaster and render residue and tool wash water are collected and settled, preventing discharge to stormwater drains or waterways.

Drawing scale 1:50

One unit on the drawing represents fifty of the same units on site, so a 25 millimetre line on the sheet represents 1250 millimetres of real building.

Reduced level

A height expressed in metres relative to a survey datum, usually to three decimal places. Positive values sit above the datum and negative values below it.

Drawing precedence

The order used to resolve conflicts, normally specification first, then large-scale details, then general drawings. Written dimensions override measurements scaled from the sheet.

Floor-to-floor height

The vertical distance from one finished floor level to the finished floor level above. It differs from ceiling height, which is measured to the ceiling lining.

Detail callout bubble

A reference symbol on a drawing giving the detail number and the sheet where the enlarged view appears. The arrow shows the direction of view.

Stainless steel trowel

A finishing trowel used to compact and polish the plaster surface. It produces a denser face than a steel trowel and reduces the risk of overworking moisture to the surface.

Wood float purpose

A timber float textures and compacts a coat, leaving an open, keyed surface that gives mechanical grip for the next coat of plaster or render.

Mixing paddle speed

Plaster is mixed at low speed, roughly 400 to 600 revolutions per minute, to blend the powder without entraining air that weakens the set.

Rotor-stator cleaning

The pump chamber of a render spray machine is flushed and cleaned daily, and the hose is depressurised before any coupling is loosened.

Screed straightness check

Before use, rules and screeds are sighted or checked against a known straight edge, because a warped screed transfers its error into the finished plane.

Background suction control

Porous masonry draws water from fresh plaster. Dampening or priming the background slows suction so the mix retains enough water to set and gain strength.

Dot and screed method

Dots are fixed plumb and level at intervals, screeds are run between them, and the plane is checked with a straight edge before plastering begins.

Bonding agent function

A primer or slurry applied to a background to control suction or provide adhesion. In wet areas the film must not remain water-soluble and weak.

Angle bead

A prefabricated profile fixed to an external corner to form a straight, protected arris. It is set plumb and true before the plaster or render coat is applied.

Mechanical key

A scored, spattered or meshed surface that gives plaster something to grip. Smooth concrete and dense backgrounds need a key to prevent shelling.

Gypsum finish coat

The final thin coat of gypsum plaster, commonly about two to three millimetres, applied over a set and keyed backing coat and trowelled to a smooth face.

Retempering prohibition

Adding water to plaster that has begun to stiffen is not permitted, because it breaks the set structure and produces a weak, dusty surface.

Internal angle sequence

In an internal corner the first wall is finished, then the adjoining wall is worked and the angle closed with an internal corner trowel before the first wall sets.

Crazing cause

A network of fine surface cracks caused by shrinkage as the plaster dries too quickly. Controlled drying and correct mix reduce the risk.

Cement lime sand render

A common external render mix of one part cement, one part lime and six parts sand by volume. Richer mixes shrink more and crack more readily.

Scratch coat

The first render coat, typically eight to ten millimetres thick, scored with a comb or scratched to form a key for the following coat.

Render control joint

A deliberate break in the render, formed with a bead at changes of substrate or at set spacings, that allows movement without random cracking.

Efflorescence

A white salt deposit left on the surface as moisture evaporates from masonry or render. It is brushed off dry and the moisture source is corrected.

Polished plaster sheen

The sheen comes from trowel pressure applied at the right stage of set, which compacts the material. Timing and pressure must be consistent across the wall.

Approved sample panel

A small area finished on site and accepted by the client as the benchmark for colour, texture and sheen. It is retained for comparison during the works.

Pigment batching

Coloured oxides are weighed, not measured by volume, and one pigment batch is used for a whole elevation so the colour stays consistent.

Drummy plaster repair

Hollow, unbonded plaster is cut back to sound material, the background is keyed and primed, and the patch is filled and blended into the surrounding finish.