Surface preparation before plastering: what is the process of roughening the background (e.g., brick or concrete) called to improve mechanical key and bond?

Introduction / Context:
Plaster adherence depends on a good mechanical key and clean surface. Site teams prepare masonry or concrete backgrounds appropriately to prevent debonding, hollow sounds, and delamination of plaster coats.

Given Data / Assumptions:

• Background is dense or smooth (e.g., concrete, RCC, or well-burnt bricks).
• The goal is to improve bond for the first plaster coat (scratch or rendering coat).
• Terminology reflects common site practice.

Concept / Approach:
Hacking involves chipping/roughening the surface to create indentations so that plaster can key into the background. Dubbing means leveling out major undulations before finishing coats. Peeling and blistering are defects in finished plaster, not preparation processes.

Step-by-Step Solution:
Identify the preparation step for roughening: hacking.Exclude defect terms (peeling/blistering) and leveling term (dubbing).

Verification / Alternative check:
Specifications often require a quantified hacking density (e.g., number of hacks per square meter) on RCC surfaces before plastering.

Why Other Options Are Wrong:

• Peeling/blistering: symptoms of failure, not preparatory steps.
• Dubbing: pre-leveling of hollows, not roughening for key.

Common Pitfalls:

• Skipping hacking on smooth RCC, leading to plaster debonding.

Final Answer:
hacking