California Contractor License — Class B (General Building) — Study Guide

California Contractor License — Class B (General Building) — Study Guide

Issuing body: California Contractors State License Board (CSLB), Department of Consumer Affairs Jurisdiction: California, United States Level: Professional license (license_to_practice: true — legally mandatory) Prerequisites: 18+ years old; SSN or ITIN; 4 years of journeyperson-level (or foreman/supervisor/contractor) experience in the classification within the last 10 years; pass the Law & Business exam, the Class B trade exam, and the open-book asbestos exam; $15,000 contractor bond (current statutory amount — verify at cslb.ca.gov, as the legislature adjusts it); workers' compensation insurance (or exemption filing if no employees). Renewal: Every 2 years with CSLB (fees; continuing education not generally required for renewal).

1. The legal reality (read this first)

In California, any person or entity that constructs or alters a structure for $500 or more in total (labor + materials) must hold a CSLB license — contracting without one is a misdemeanor carrying jail time and administrative fines, and unlicensed contractors face severe limits on collecting payment. Class B (General Building) covers framing/carpentry plus two or more unrelated trades — it is the license for ground-up buildings and major remodels. (A B-licensee doing only one trade, or a specialty trade alone, needs the matching C-classification.) You may self-perform framing/carpentry and subcontract the rest, or subcontract everything — but every subcontractor must hold the right classification.

2. How the license is earned

1. Document 4 years of journeyperson-level experience in general building within the last 10 years (certified by a qualifying individual — employer, union, or licensed contractor who observed the work).
2. Apply to CSLB with the $450 application fee (fee schedule changes — verify current amounts at cslb.ca.gov); get fingerprinted (background check).
3. Pass two closed-book exams at a PSI center (per CSLB's contracted vendor):
   • Law & Business: ~115 multiple-choice questions, ~3–3.5 hours. Contracts, licensing law, business management, safety, labor law.
   • Class B Trade: ~115 multiple-choice questions, ~3–3.5 hours. Construction methods, materials, estimating, blueprint reading, building codes.
   • Passing is by scaled cut score (roughly a 72% equivalent; CSLB does not publish a fixed raw percentage — prep providers cite ~70–72%). Confirm the current scoring on cslb.ca.gov; treat exact question counts as approximate since CSLB adjusts forms.
   • 18 months from application acceptance to pass both; 21-day wait to retake a failed exam; a passed exam stays valid 5 years.
4. Pass the open-book asbestos certification exam (mailed after passing — covers asbestos awareness/handling rules).
5. File the $15,000 contractor bond and workers' comp insurance; pay the initial license fee; the license issues.

Exam strategy: the Law & Business exam is identical across all classifications — master it first (it's the highest-leverage section). It's scenario-heavy: "a contractor does X — what violation, what remedy?" Memorize the numbers in section 6 cold (down-payment caps, lien deadlines, bond amounts) because the exam tests exact figures.

3. Knowledge domains

3.1 Licensing law and CSLB enforcement

License classifications (A = general engineering, B = general building, C = specialty trades — 40+ of them); qualifier rules (the Responsible Managing Employee/Officer who holds the experience); license renewal, inactive status, and disciplinary grounds (fraud, abandonment, willful code violations). Home improvement contracts (B&P Code §§ 7150+): strict form requirements — the exam tests the mandatory contract elements (license number, down-payment limits, notice of right to cancel, mechanics-lien warning).

3.2 Contract requirements and business practices

• Down payment: on home-improvement contracts, max the lesser of $1,000 or 10% of the contract price (excluding finance charges) — the single most-tested number on the exam.
• Progress payments: must reflect work performed/materials delivered; retention practices.
• Change orders: must be in writing, signed, priced before work (or with an agreed pricing method) — verbal change orders are the industry's #1 dispute source and the exam's #1 scenario.
• Mechanics liens (CA Civil Code §§ 8000+): the contractor's security. Chain: 20-day preliminary notice (serve within 20 days of first furnishing labor/materials — late notice only covers the 20 days before service + after); record the claim of lien within 90 days of completion (or 30 days after notice of completion/cessation, whichever shortens); foreclose (file suit) within 90 days of recording. Miss a deadline and the lien right evaporates — the exam builds entire scenarios around one missed date. Lien releases: conditional vs. unconditional, progress vs. final — know which to sign when.
• Stop notices on public works (the public-project analogue, since you can't lien public property); payment bonds under the Little Miller Act (CA Civil Code § 9550) for public works over $25,000.

3.3 Labor, safety, and employment law

Workers' comp mandatory with employees (exemption certificate only if truly no employees — misclassification is a CSLB disciplinary ground); prevailing wage on public works (CA Labor Code § 1720+, DIR determinations, certified payrolls, apprenticeship ratios); Cal/OSHA (Title 8) — Injury and Illness Prevention Program (IIPP, 8 CCR 3203) required of every employer; heat-illness prevention (8 CCR 3395); fall protection triggers. The exam tests employer duties, not trade technique.

3.4 Trade knowledge: estimating, scheduling, codes

• Estimating: quantity takeoffs (concrete in cubic yards with ~5–10% waste factor; lumber board-feet; roofing squares = 100 sq ft), labor productivity rates, overhead and profit markup math (markup on cost vs. margin on price — markup 20% on cost ≠ 20% margin), bid-day procedures.
• Scheduling: bar charts, CPM basics (the exam's trade-side scheduling is lighter than the CCM's — know ES/EF/float conceptually), submittal and procurement lead times.
• Codes: CBC/CRC fundamentals frequently tested — footing depths below frost/undisturbed soil, anchor-bolt spacing and embedment for seismic (1/2" bolts, 6' o.c. max, 7" embedment in the CRC's prescriptive path), shear-wall holdowns, Title 24 energy basics, egress and stair geometry (7-11 rule: 7" max riser, 11" min tread). The exam tests recognition of code requirements, not design.
• Safety math: excavation sloping/benching triggers (5' depth), scaffold and ladder rules, electrical clearances.

4. Key numbers (memorize — the exam tests exact figures)

5. Worked examples

Example 1 — Markup vs. margin. Job costs $80,000; you want a 20% margin on price. Price = 80,000 / (1 − 0.20) = $100,000. (Marking up 20% on cost gives $96,000 — a $4,000 error the exam loves.) Reverse: a $100,000 bid at 20% margin leaves $80,000 cost budget.

Example 2 — Lien deadline chain. Subcontractor first furnished materials March 10, project completed June 30, no notice of completion filed. Preliminary notice must be served by March 30 (20 days). Lien must be recorded by September 28 (90 days after completion). Suit to foreclose within 90 days of recording. If the sub served prelim notice April 15 (late), it covers only work from March 26 forward — the March 10–25 work is unsecured.

Example 3 — Down payment. Home-improvement contract price $48,000. Max down payment = lesser of $1,000 or $4,800 → $1,000. A contractor taking $4,800 "10%" violates the cap — the exam's standard trap (10% only governs when it's less than $1,000, i.e., contracts under $10,000).

Example 4 — Concrete takeoff. Footing: 120 linear feet, 24" wide × 12" deep. Volume = 120 × 2 × 1 = 240 cu ft = 8.89 CY; +7% waste → 9.5 CY → order 10 CY (ready-mix minimums and truck sizes govern the final call).

Example 5 — Experience qualification. Applicant has 3 years as a journeyman carpenter + 1 year as a foreman on ground-up residential, all within the last 6 years, certified by the licensed employer. Qualifies (4 years journeyperson-level within 10). An applicant with 4 years as a laborer does not — the level matters, not just the years.

6. Pitfalls and trap patterns

• The $1,000/10% rule. "Lesser of" — the exam always offers the 10% figure as a distractor on big contracts.
• Lien deadlines are jurisdictional. One missed date kills the lien; the exam chains them so a single error cascades.
• Class B ≠ do anything. B covers framing/carpentry + 2+ unrelated trades; fire sprinklers, electrical, plumbing, HVAC, and other specialty work need C-licensees (or the right classification) — the exam tests classification boundaries.
• Employees vs. independent contractors. Calling workers "1099" doesn't make them so (ABC test); misclassification risks CSLB discipline, EDD assessment, and comp violations.
• Verbal change orders. Always wrong on the exam. Written, signed, priced — no exceptions in the answer key.

7. Practice problems (answers at end)

1. Home-improvement contract $8,000. Maximum legal down payment?
2. A sub first works April 1, serves prelim notice April 25, job completes August 15 (no NOC). Which work is lien-secured, and by when must the lien be recorded?
3. Costs $120,000, target margin 25% on price. Bid price?
4. True/false: A Class B licensee may self-perform the electrical work on a ground-up duplex.
5. Slab 30' × 40' × 4" thick. Cubic yards before waste?
6. A contractor abandons a job after taking 50% upfront on a $60,000 home-improvement contract with 10% complete. Name two violations.
7. What's the difference between a conditional and an unconditional lien release, and when do you sign each?

Answers: 1. Lesser of $1,000 or $800 → $800. 2. Work from April 5 forward (20 days before April 25); record by November 13 (90 days after Aug 15). 3. 120,000/0.75 = $160,000. 4. False — electrical requires the C-10 classification (must subcontract to a C-10). 5. 30×40×(4/12) = 400 cu ft = 14.8 CY. 6. Excessive down payment (over $1,000/10%) and abandonment without legal excuse (disciplinary ground; also potential fraud). 7. Conditional releases upon expected payment (progress payments — effective only when paid); unconditional only when payment is confirmed in hand (final payment) — signing unconditional early forfeits lien rights for money you haven't received.

Exam-format note: question counts, timing, and the scaled cut score above are per CSLB-published materials and prep-provider summaries as of 2026; CSLB adjusts forms periodically — confirm current details at cslb.ca.gov before booking.

Original ETS reference writing, verified against public sources on 2026-09-30. Thin sourcing is flagged inline. Not legal advice — confirm current editions with the issuing body.