Chapter 4 of 521% of exam

Structure Demolition

CSLB weights Structure Demolition at about 21% of the C-21 exam: pre-demolition site preparation, demolishing single- and multi-story structures, separating materials, transporting debris, and cleaning and backfilling. This page is a short survey; the PrepPass C-21 study guide teaches the section with worked examples and a full practice exam at CSLB's weights.

Prepare the site

Control utilities, remove hazardous material, correct survey deficiencies and protect people at entrances.

Entrance canopy
Protection extends at least 8 feet from the building face, at least 2 feet wider than the entrance, and carries 150 pounds per square foot.
Cal. Code Regs. tit. 8 §1735(j)

Take it down

Top down, one story at a time, with limits on openings and free-standing walls.

Top-down sequence
Exterior walls and floors are demolished from the top of the structure downward, a story at a time.
Cal. Code Regs. tit. 8 §1735(f)(1)
Walls
A wall more than one story or 12 feet high may not stand alone without lateral bracing.
Cal. Code Regs. tit. 8 §1735(m)
Debris openings
A floor opening for debris may be no larger than 25 percent of the floor area unless lateral supports remain.
Cal. Code Regs. tit. 8 §1735(f)(2)

Debris and backfill

Enclosed chutes, protected drop zones and clean, compacted fill.

Drop zones
Without chutes, the landing area is enclosed by barricades at least 42 inches high and 6 feet back.
Cal. Code Regs. tit. 8 §1736(f)
Backfill
Backfill is free of organic material, construction debris, cobbles and boulders, placed in compacted lifts.
2025 CBC §1804.3

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