The CSLB B – General Building exam, explained
The trade exam for the B license: five sections, four answer choices, a calculator on the screen and no code book in the room. Here is what CSLB publishes about it, and what it does not.
If you apply for a B – General Building license, you sit two exams: the Law and Business exam, which almost every applicant takes, and the B trade exam. The B exam is the one about building. It reaches from reading plans and pricing a job to footings, framing, the trades a general contractor coordinates, the finishes, and jobsite safety.
Most people who apply for a B already know the work. The exam still catches them in two places: numbers they have never needed on site because the plans or the inspector supplied them, and trades they have always subcontracted.
The format
| Delivery | On a computer at a PSI test center, in person |
|---|---|
| Question type | Multiple choice, four choices, one BEST answer |
| Books | Closed book. No reference materials in the room |
| Math | Some questions need calculation. A calculator is provided |
| Guessing | No penalty. Answer every question |
| Time | 3½ hours for each exam |
| Languages | English or Spanish |
| Where | PSI centers in California, or Wilsonville, Oregon |
Sources: CSLB License Examination Study Guide, General Building (B), 13E-B (03-2026); CSLB Examinations FAQ.
Two things CSLB does not publish: the number of questions on the B exam and the passing score. The study guide says “plenty of time is provided,” and CSLB's licensing booklet says the percentage needed to pass varies for each exam. Any site that quotes you a question count or a pass mark for B is guessing.
The five sections and what they weigh
The study guide splits the exam into five sections and gives each an approximate share. Each section name opens a page on what it covers, where people lose points and how to study it.
| Section | Weight |
|---|---|
| Planning and Estimating Scope of work and code compliance, catching design and construction errors, shop drawings, plans and specifications, field inspections, coordinating the job, estimating materials, equipment and labor | 15% |
| Framing and Structural Components Subfloor and wall framing, roof framing, seismic hardware, siding and stucco, decks and stairs | 20% |
| Core Trades Plumbing, electrical, HVAC, concrete, earthwork and surveying, insulation, acoustical and weatherproofing, roofing | 30% |
| Finish Trades Painting, staining, coatings and wall covering, tile and stone, floor covering, cabinets and millwork, plaster, drywall and ceilings, windows, skylights and doors, landscaping | 20% |
| Safety Personnel safety, transportation and traffic control, environmental safety | 15% |
Weights from the CSLB General Building (B) study guide, 13E-B (03-2026), for exams scheduled on or after 1 January 2025. CSLB notes the percentages are approximate.
Core Trades is 30% on its own, and seven trades share it. Framing and Finish Trades add another 40%. A framer who never touched a panel or a drain line has the most to gain in Core Trades; a remodeler who lives in finish work often has the most to gain in framing and structural. Our study plan turns the weights into hours.
Which codes the questions come from
The study guide lists the reference material behind the exam. The code books are the 2025 California editions (Title 24): the Building, Residential, Electrical, Energy, Fire, Green Building (CALGreen), Mechanical and Plumbing Codes. Alongside them: the North American Architectural Woodwork Standards, the California Manual on Uniform Traffic Control Devices, the California Vehicle Code, Cal/OSHA's Construction and Electrical Safety Orders (Title 8), and three textbooks: Fundamentals of Building Construction, Modern Carpentry and Olin's Construction Principles, Materials, and Methods.
California edits the model codes. The California Residential Code is based on the national model code but is not identical to it, and a number you learned from a national book or another state can be wrong here. A guard on a California deck, for example, has to be at least 42 inches high (City of San Ramon deck and stair handout, 2025 code cycle). When a number from a national book, another state or an older edition disagrees with a current California handout, go with California.
CSLB's licensing booklet adds that trade exams are written with licensed contractors in the classification, are updated every five to seven years, and that most include questions that refer to accompanying blueprints or drawings. The B study guide itself does not say whether the B exam includes a plan set, so be ready to read one.
Who has to take it
The person who qualifies the license, the qualifier, takes the exams. You apply for the classification your experience is in, and for a B license the trade exam is B. A general building contractor, under Business and Professions Code §7057, is one whose main business is structures that need at least two unrelated building trades or crafts. In practice that means:
- A B contractor may take a framing or carpentry job on its own, as prime or sub.
- Any other prime contract has to involve at least two unrelated trades besides framing and carpentry, unless you also hold that trade's license or subcontract it to a licensed contractor. Framing and carpentry do not count toward the two.
- Fire protection (C-16) and well drilling (C-57) always need their own license or a licensed sub.
B-2 Residential Remodeling is a separate classification: existing wood-frame homes, at least three unrelated trades per contract, and no structural work on load-bearing parts. If that is your work, check which exam your application is referred to.
CSLB can waive the trade exam in limited cases: if you are the qualifier on a license in good standing in the same classification, have been one within the last five years, or passed both exams in that classification within the last five years. Even then you document four years of journey-level experience on the application.
Sources: CSLB Description of Classifications (B&P Code §§7057, 7057.5); CSLB Get Licensed to Build, Licensing Examinations Q3–Q4.
How it pairs with Law and Business
The two exams are separate appointments with separate PSI fees, and you can sit them on the same day or on different days. Each gets its own 3½ hours. You have 18 months from the day CSLB accepts your application to pass both, and a failed exam can be retaken after 21 calendar days. The Law and Business exam is about running the business; B is about the building. There is a little overlap in Safety: Law and Business asks about the employer's programs and reporting duties, B asks about the work on site.
Booking, ID, what stays outside the room and how results work are the same PSI process for both: see exam day at PSI. If one of them goes wrong, what happens after a fail applies to B as well.
Taking it in Spanish
B – General Building is one of the ten CSLB exams offered in Spanish. If you ask for a translator for one of those ten, CSLB requires you to take the Spanish version instead. The code books the exam is built from are in English, so learn the English name of each material and rule as well as the Spanish one. Details: taking the exam in Spanish.
How to prepare
- Start with a scored test. Find your weakest of the five sections before you open a book. Our free B test has 25 questions and scores each section.
- Spend by weight. Core Trades first, then Framing and Finish Trades.
- Drill the math. Areas, volumes, board feet, roof slopes, piece counts. See estimating math on the B exam.
- Learn California numbers as numbers. Riser heights, bolt spacing, clearances, slopes. Closed book means recall.
- Sit a full timed practice exam. Three and a half hours in one sitting is its own skill.
Common questions
How many questions are on the B exam?
CSLB does not publish it. It publishes the five sections and their approximate weights, and gives 3½ hours for each exam. Plan around the weights.
What score do you need to pass the B exam?
CSLB does not publish one. Its licensing booklet says the percentage needed to pass varies for each exam. A passing report only says you passed; a failing report shows your score and a breakdown by section.
Is the B exam open book?
No. Closed book, four choices, one BEST answer. A calculator is provided for the math; you cannot bring your own.
Can I take the B exam in Spanish?
Yes. It is one of the ten CSLB exams offered in Spanish. Esta página en español.
Do I also need the Law and Business exam?
Almost always. Both exams are required unless you qualify for a waiver, and you have 18 months from the day your application is accepted to pass them.
Last reviewed 29 September 2026 against the CSLB License Examination Study Guide for General Building (B), 13E-B (03-2026), the CSLB Examinations FAQ, Get Licensed to Build and CSLB's Description of Classifications. Rules change; check cslb.ca.gov before acting on anything here. Study guidance, not legal advice. We are not affiliated with CSLB or PSI.