Installation and Application Techniques
What the candidate must know
Installation covers placing, spreading, compacting, and finishing the mud floor to the specified thickness and level. Concepts: uniform placement in lifts, compaction method (ramming, tamping, or mechanical compaction), edge and joint detailing, and working to screed guides or formwork. Understand that the floor must be placed over an approved subgrade and that thickness must be maintained - thin spots are weak spots. Know how to handle construction joints and how to avoid segregation when placing.
Traps
Questions often test sequence: subgrade approval must precede placement, and leveling must happen while the mix is workable. A frequent trap is "troweling in" a low spot with a thin skim after the floor has begun to set - this creates a weak, delaminating patch. Another is overworking the surface, which draws fines and water to the top and produces a dusty, weak crust. Also watch for edge compaction being skipped because it is awkward.
Worked example / rule of thumb
Rule of thumb: place, spread, and compact each lift before it stiffens, and check thickness at several points against the specified value. Example: if a low spot appears after the surface has stiffened, the correct action is to remove and replace that area with fresh compatible mix, not to feather a thin patch over it. Keep screed guides set to the finished level so leveling is done by the guide, not by eye.