Pre-placement Preparation
Pre-placement Preparation is about 27% of the exam: demolition, grading and excavating; layout and forming; drains and moisture barriers; and reinforcement and embedded items. All of it must be right, and inspected, before the first truck arrives. For worked examples, traps and full explanations, see the PrepPass CSLB C-8 Concrete Study Guide.
Subgrade and excavation
A slab needs a uniform subgrade more than a strong one — no hard or soft spots. Proof-roll with a loaded rubber-tired vehicle to find soft areas. Inside the 24-inch tolerance zone of a marked utility, expose it with hand tools before power equipment. Excavations 5 ft or deeper need a protective system; soil is classified by a competent person, and maximum slopes under 20 ft are 3/4:1 (Type A), 1:1 (Type B) and 1½:1 (Type C).
Layout and forms
Check the control stakes, carry lines on offsets or batter boards, and square corners with 3-4-5 or equal diagonals. Forms are sheathing backed by studs and walers, held by ties and braced by kickers. Fluid pressure is about 150 pcf times the depth; fast pours, cold concrete and heavy vibration raise it. Oil forms before the steel goes in, never on the steel, and never with straight diesel.
Drains, moisture barriers, steel and embeds
Drain rock wrapped in filter fabric around perforated pipe, with continuous fall to an outlet. Vapor retarders go down in the widest practical sheets with the specified laps, and torn material is replaced. Reinforcement must be clean enough to bond, supported on chairs or precast blocks, tied rather than tack-welded, and covered as specified. Anchor bolts, sleeves and waterstops are set and secured before the pour.
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