C-21 Building Moving/Demolition exam questions, with answers
10 practice questions for the CSLB Building Moving/Demolition trade exam, each with the answer, a plain explanation and the source it rests on.
These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-21 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.
The C-21 exam has 5 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-21 test.
Planning and Estimating · 25% of the exam
Evaluating plans and specifications; evaluating hazardous materials surveys; evaluating job site readiness; determining job methods and equipment; estimating project costs.
1. On a Caltrans contract to remove an old maintenance yard building, the project plans show one requirement for breaking out the floor slab, and a standard specifications section sets a different one. The special provisions are silent. Under Caltrans Standard Specifications (2025) 5-1.02, which contract part governs?
- The standard plans
- The revised standard plans
- The project plans
- The standard specifications
Show the answer
Answer: C. Section 5-1.02 ranks the contract parts in descending order: special provisions, project plans, standard specifications, revised standard plans, standard plans, and supplemental project information. With the special provisions silent, the project plans outrank the standard specifications. If a discrepancy or confusion remains, submit an RFI.
Source: Caltrans Standard Specifications 2025, 5-1.02 Contract Components
2. The pre-demolition asbestos survey of a commercial building subject to the federal EPA asbestos NESHAP measures the regulated asbestos-containing material (RACM) on its pipes. Under 40 CFR 61.145(a)(1), the full notification and emission control requirements apply when the RACM on pipes alone totals at least how many linear feet?
- 35 linear ft
- 100 linear ft
- 160 linear ft
- 260 linear ft
Show the answer
Answer: D. 40 CFR 61.145(a)(1) applies all of paragraphs (b) and (c) to a demolition when the combined RACM is at least 260 linear feet on pipes, at least 160 square feet on other facility components, or at least 35 cubic feet off facility components where it could not be measured before. The 160 and 35 figures are the area and volume triggers, not the pipe trigger, and 100 is not a NESHAP trigger.
Source: 40 CFR 61.145(a)(1), 40 CFR Part 61 Subpart M, National Emission Standard for Asbestos (2025 CFR)
Project Preparation · 20% of the exam
Permitting and notification; mobilizing labor, equipment and materials; developing recycling plans; removing hazardous materials.
3. At lunch break on a demolition job, your operator leaves a diesel wheel loader running in the staging yard with nobody using it. The loader is covered by CARB's off-road diesel fleet regulation. Under 13 CCR 2449, it may idle for no more than how many consecutive minutes?
- 5 minutes
- 10 minutes
- 15 minutes
- 30 minutes
Show the answer
Answer: A. 13 CCR 2449, CARB's In-Use Off-Road Diesel-Fueled Fleets regulation, says that no vehicle or engine subject to it may idle for more than five consecutive minutes, apart from the exceptions the rule lists. A loader left running at lunch is plain idling, so the 10-, 15- and 30-minute figures are all too long.
4. An old office building will be torn down so a new retail center can be built under a city building permit, and the city has no stricter ordinance. Under 2025 CALGreen 5.408.1 (nonresidential), at least what share of the nonhazardous construction and demolition waste must be recycled or salvaged?
- 50%
- 60%
- 65%
- 75%
Show the answer
Answer: C. 2025 CALGreen 5.408.1 for nonresidential projects (4.408.1 is the residential twin) requires recycling or salvage of at least 65 percent of the nonhazardous construction and demolition waste, or compliance with a stricter local ordinance. Excavated soil and land-clearing debris are not counted. 50% and 60% are too low, and 75% would only apply if a local ordinance demanded it.
Source: 2025 CALGreen 5.408.1, 2025 California Green Building Standards Code (CALGreen), Title 24, Part 11
Building Moving · 13% of the exam
Moving preparation; determining weight and structural integrity; building raising and lowering; building support and transportation.
5. The route you planned for relocating a two-story house to its new lot crosses a short-line railroad's main line. Which written notice does California Vehicle Code 35789 require before the house goes over the rails?
- To the railroad's division or district superintendent, at least 12 hours ahead
- To the railroad's division or district superintendent, at least 36 hours ahead
- To the California Public Utilities Commission, at least 72 hours ahead
- To the county sheriff and to the railroad company, at least 24 hours ahead
Show the answer
Answer: B. Vehicle Code 35789 requires a house mover who moves a building across railroad tracks to give the division or district superintendent of the railroad operating them written notice at least 36 hours before. The notice names the street or road of the crossing and the approximate time of day. The other recipients and time limits are not in the section.
Source: California Vehicle Code 35789
6. Your crew has jacked a house 10 inches off its old foundation, and the foreman wants everyone to break for lunch with the house resting on the jacks alone. Under federal OSHA 29 CFR 1910.244(a)(2), what is required once a load has been raised?
- Crib, block or otherwise secure the load at once
- Lock the jack handles and post one person to watch the jacks
- Secure the load with cribbing before the end of the shift
- Crib the load only if it will stay raised over an hour
Show the answer
Answer: A. Federal OSHA 29 CFR 1910.244(a)(2)(iii) says that after the load has been raised, it shall be cribbed, blocked or otherwise secured at once. A jack is for lifting, not for holding a house; a watchman, a deadline at shift end, or a one-hour rule do not meet the at-once requirement.
Source: 29 CFR 1910.244(a)(2)(iii) (federal OSHA), 29 CFR 1910.244(a) Jacks (federal OSHA)
Structure Demolition · 21% of the exam
Pre-demolition site preparation; demolition of single- and multi-story structures; separating demolished materials; transporting materials and debris; cleaning and backfilling job sites.
7. Before your laborers may begin wrecking a three-story apartment building, what does 8 CCR 1734(b) require?
- A written survey by a registered civil engineer of the foundation and soil conditions
- A written survey by the building official of the roof, chimneys and parapet walls
- A spoken check by the foreman of the exits, stairs and fire extinguishers on each floor
- A written survey by a qualified person of the framing, floors, walls and collapse risk
Show the answer
Answer: D. 8 CCR 1734(b)(1) requires a qualified person, before employees start demolition, to survey the structure for the condition of the framing, floors and walls and the possibility of an unplanned collapse, and to check exposed adjacent structures. Under 1734(b)(2) the survey is written, kept on the job site and kept for the whole project.
8. Your crew will hand-wreck the exterior walls and floors of a four-story brick building. Apart from preparatory work such as cutting holes for chutes, in what order does 8 CCR 1735(f)(1) require this work to go?
- From the ground floor up, so debris can be stored on the upper floors
- From the top down, removing each story before starting the one below
- In any order that the qualified person approves in the written survey
- Exterior walls of every story first, then the floors from the top down
Show the answer
Answer: B. 8 CCR 1735(f)(1) requires demolition of exterior walls and floor construction to begin at the top of the structure and proceed downward, with each story of wall and floor removed and dropped into the storage space before work starts on the story below. Stripping all walls first, working bottom-up or leaving the order to the survey do not meet it.
Safety · 21% of the exam
Job site safety; personnel safety; implementing traffic controls; personal protective equipment (PPE).
9. A laborer suffers an injury that meets the Title 8 definition of a serious injury when a ceiling collapses during an interior strip-out. No exigent circumstances exist. Under 8 CCR 342(a), what is the latest time after you know of it to report the injury to Cal/OSHA?
- 8 hours
- 24 hours
- 48 hours
- 72 hours
Show the answer
Answer: A. 8 CCR 342(a) requires the employer to report a serious injury, illness or death immediately, by telephone or the Division's online mechanism; immediately means as soon as practically possible but not longer than 8 hours after the employer knows or should have known. Only if the employer can show exigent circumstances may the report come up to 24 hours after the incident.
10. A crane will block one lane of a street while it lifts a rooftop unit off a building being demolished, and your carpenter volunteers to flag traffic although he has never done it. Under 8 CCR 1599(g), when must he be trained in the fundamentals of flagging moving traffic?
- Within 10 working days after he begins to work as a flagger
- Within 30 days, while he works next to a trained flagger
- Before he is assigned to flag, including a demonstration
- Before his first night shift, since daytime work needs none
Show the answer
Answer: C. 8 CCR 1599(g) says flaggers shall be trained in the proper fundamentals of flagging moving traffic before being assigned as flaggers. The training follows the California MUTCD and site conditions and includes a trainee demonstration of proper flagging. Training later, on the job or only for night work does not meet the rule.
Source: 8 CCR §1599(g), Cal. Code Regs. Title 8, §1599. Flaggers (Construction Safety Orders)
Where to go from here
How the license works, from experience to fees: how to get a C-21 license. Everything about the course: the C-21 exam page.
Questions from our free C-21 test, written from CSLB License Examination Study Guide, Building Moving and Demolition (C-21), form 13E-21 (03-2026), for examinations scheduled on or after July 1, 2024. CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.