The Concrete (C-8) Exam: Format, Topics, and Passing Score
The Concrete (C-8) exam is a closed-book, computer-based multiple-choice test with four choices per question. CSLB gives 3.5 hours for each exam, but it does not publish a universal question count or fixed public passing percentage. The official guide for exams scheduled on or after March 1, 2026 gives you the current topic weights; that blueprint is more useful for planning than a guessed score.
The C-8 exam at a glance
| Detail | What you can verify |
|---|---|
| Format | Closed-book, multiple choice, four choices per question (CSLB C-8 study guide) |
| Time | 3-1/2 hours for each examination (CSLB exam FAQ) |
| Location | In person at a PSI test center; trade exams are completed in California or Oregon (CSLB exam FAQ) |
| Question count | CSLB does not publish a universal count in the sources above |
| Passing score | CSLB tells you the percentage needed at the test site; it does not publish one fixed public percentage (CSLB studying) |
| Retake timing | Wait 21 calendar days after an attempt; a fee is required for each registration (PSI bulletin) |
| Exam fee | $51.43 per registration in the current PSI bulletin (PSI) |
The exam is not open-book, and the calculator is provided when a question requires computation. CSLB also says there is no penalty for guessing. Use the official rules to manage time, but do not turn “no penalty” into permission to rush through calculations.
Where the C-8 content is concentrated
The official guide divides the Concrete exam into five approximate sections:
| Section | Approximate weight | What to study |
|---|---|---|
| Planning and Estimating | 28% | Planning concrete projects; estimating concrete projects |
| Pre-placement Preparation | 27% | Demolition, grading, excavation, layout, forming, drains, moisture barriers, reinforcement, embedded items |
| Placing and Finishing | 17% | Placement, finishes, curing, testing |
| Post-placement Tasks | 7% | Stains, sealers, stripping forms, repair, grouting, caulking |
| Safety | 21% | Employee safety and job-site safety |
The best study order follows the weights, but it should not ignore the 7% section. A small section can still contain questions you either know or miss. The planning insight is to spend the first block on planning, pre-placement, and safety, then use the smaller sections to close gaps.
A practical two-week study plan
- Days 1–2: map the exam. Read the official CSLB study guide and the C-8 guide. Mark each topic as familiar, rusty, or unknown.
- Days 3–6: build the core. Study planning and estimating, then pre-placement preparation. Work calculation and sequence questions on paper before checking your answer.
- Days 7–9: cover placement and safety. Review finishing, curing, testing, employee safety, and job-site controls. Explain each missed idea in your own words.
- Days 10–11: close the small section. Review post-placement tasks, then return to the two sections where your mistakes are most consistent.
- Days 12–14: simulate and repair. Take timed practice sets, review every miss, and repeat the weak topic until you are consistently scoring 85% or better in practice.
This sequence uses the official weights as a triage tool, not as a promise about the next exam form. The exam board can update guides, so check the version date before you begin.
Worked example: convert a slab volume before you practice
A rectangular slab is 12 feet wide, 25 feet long, and 4 inches thick. Approximately how many cubic yards of concrete does it contain before any project-specific allowance?
- A. 1.85 cubic yards
- B. 3.70 cubic yards
- C. 7.41 cubic yards
- D. 12.00 cubic yards
Correct answer: B. 3.70 cubic yards. Convert 4 inches to one-third of a foot, multiply 12 × 25 × 1/3 to get 100 cubic feet, then divide by 27 cubic feet per cubic yard. The point is the sequence: convert units first, then calculate volume, then apply any job-specific ordering allowance separately.
This is an original study example, not a CSLB exam question. CSLB questions are confidential.
How to practice for the C-8 exam
Start with the free CSLB guide, then use the Peerless Concrete (C-8) Study Guide Book to learn the terms and work sequences. Use the Concrete (C-8) Online Practice Exam to measure recall and timing. If you also need Law and Business, the C-8 Silver bundle combines the trade book and trade practice exam; the Gold option adds Law and Business practice when listed.
Do not count a question as “known” because the explanation looks familiar. Mark it known only when you can identify the tested idea, reject the distractors, and explain the answer without looking back. That review loop is where the practice becomes useful.
FAQ
How many questions are on the C-8 exam?
CSLB does not publish a universal question count in the current C-8 study guide or its exam FAQ. What CSLB does publish is the format: closed book, multiple choice with four choices, and a calculator provided when needed. Prepare from the official topic weights rather than a number copied from an unverified site.
What is the C-8 passing score?
CSLB does not publish one fixed public percentage for the C-8 exam. Its studying guidance says candidates are informed at the test site about the percentage needed to pass, and a passing report does not show the overall score. Treat practice performance as a readiness signal, not a state-issued cutoff.
Can I take the C-8 exam online?
No. CSLB says qualifying examinations must be taken in person at a PSI location. Trade exams must be completed in California or Oregon. Schedule only after CSLB refers your accepted application for testing, then confirm the current site and appointment details with PSI.
How soon can I retake the C-8 exam?
The PSI examination bulletin says a candidate who fails may retake after 21 calendar days, as long as the application remains valid, and must pay the examination fee for each registration. Use the waiting period to repair the topic that caused the miss instead of repeating the same study session.
Sources
- CSLB: Concrete (C-8) study guide
- CSLB: Examination FAQ
- CSLB: Studying for the Examination
- PSI: California contractor examination bulletin
Peerless Institute has helped California contractors prepare for CSLB exams since 1953. Use the Concrete (C-8) Study Guide Book, the Concrete Online Practice Exam, or the C-8 study and practice bundle to build a focused study loop.