Plastering operations — term for working a flat to receive the finishing coat In plasterwork, what is the operation called in which the undercoat is worked and made true, level, and keyed with a float so that it is ready to receive the finishing coat?

Introduction / Context:
Plastering is applied in stages: preparation of background, dubbing out (filling hollows), undercoat(s), floating, and finish coat. Proper terminology matters because each stage has specific workmanship requirements that affect durability and appearance of the final surface.

Given Data / Assumptions:

• The question refers to preparing the undercoat to receive the finishing coat.
• Tool used: float (wood or plastic) to level and key the surface.
• Conventional multi-coat plaster system.

Concept / Approach:
Floating is the process of working the undercoat with a float to produce an even, plane, and slightly keyed surface appropriate for the finish. Dubbing out fills localized depressions before floating. Knetting is not a standard plastering term; blistering is a defect where bubbles appear due to poor adhesion or rapid drying, not a planned operation.

Step-by-Step Solution:

Verification / Alternative check:
Trade specifications describe “float coat” and “floating” as essential steps prior to the finish, especially in cement-lime-sand systems.

Why Other Options Are Wrong:

• dubbing out: preliminary filling, not final preparation for the finish.
• knetting: not recognised as a plastering operation.
• blistering: a failure mode, not a process.

Common Pitfalls:
Skipping floating leads to uneven finish, poor key for the top coat, and increased cracking due to variable thickness.

Final Answer:
floating