Licensed sheet metal contractor fabricating HVAC ductwork

Become a Licensed C-43 Sheet Metal Contractor

The C-43 Sheet Metal classification covers fabricated metal that protects and ventilates buildings, ductwork, gutters, flashing, metal roofing, and commercial kitchen exhaust.

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Requirements

Minimum age: 18+ is CSLB's normal applicant path. A minor may qualify only after a court appoints a guardian (BPC §7065.5)
Experience required: 4 full-time-equivalent years of journey-level experience within the past 10 years; CSLB prorates part-time work
Contractor bond: $25,000

About the Exam

Exam format: 2 parts (Law & Business + Trade)
Law & Business exam: 115 questions
School-observed scores: 65% Law / 65% Trade; not published as fixed by CSLB
Application fee: $450

License renews every 2 years. Governing code: CCR §832.43

About this classification

What does a C-43 Sheet Metal contractor do?

A C-43 Sheet Metal Contractor selects, cuts, shapes, fabricates, and installs sheet metal such as cornices, flashings, gutters, leaders, pans, kitchen equipment, ductwork (including insulation), patented chimneys, metal flues, metal roofing systems, and other installations requiring sheet metal. (Per California Code of Regulations, Title 16, §832.43.)

The C-43 is a fabrication-and-installation license. California requires a C-43 contractor for sheet-metal ductwork, gutters and downspouts, flashing, custom cornices and trim, commercial kitchen hood exhaust, and standing-seam metal roofing. The license centers on functional sheet metal, distinct from ornamental metalwork (C-23) and complete HVAC systems (C-20).

Official source: CSLB C-43 classification · CSLB fee schedule Last reviewed: March 2026

Scope of work

HVAC ductwork systems and duct insulation
Gutters, downspouts, and leaders
Flashing and pans
Commercial kitchen hood and exhaust equipment
Custom cornices, trim, and architectural sheet metal
Standing-seam and other metal roofing systems
Patented chimneys and metal flues
Dryer, bath, and make-up-air venting
Sheet-metal fabrication for specialized installations

High-demand specialties

Commercial Ductwork, Fabricating and installing HVAC duct for large buildings
Kitchen Exhaust, Restaurant hood and exhaust systems are a specialized niche
Architectural Metal, Custom cornices, panels, and standing-seam roofing
Gutters & Flashing, Steady weatherproofing work on new and existing buildings

Important notes

A C-43 contractor can fabricate and install standalone ductwork, but installing a complete HVAC system, furnaces, AC, and controls, requires a C-20 (HVAC) license.
The C-43 covers functional sheet metal. Decorative and architectural-treatment metalwork in brass, bronze, copper, or wrought iron falls under the C-23 (Ornamental Metal).
Custom sheet-metal roofing is within C-43 scope; the broader range of roofing materials (composition, tile, membrane) requires a C-39 (Roofing) license.
Any sheet-metal project over $1,000 requires a licensed contractor. California also requires workers' compensation coverage for licensees.

The CSLB exam

What's on the C-43 Sheet Metal exam?

California requires you to pass a two-part CSLB exam: the Law & Business exam (the same for every classification) and the C-43 Sheet Metal trade exam. CSLS has observed scores of 65% for Law & Business and 65% for the C-43 trade exam. CSLB does not publish fixed passing scores and may vary them by exam version.

Law & Business

Same for all classifications

115 questions, multiple choice, computer-based
3.5 hours allotted
Topics: California contractor law, business management, safety, estimating, project management

C-43 Trade Exam

Sheet Metal-specific

about 100 questions, multiple choice, computer-based
3.5 hours allotted
Topics: sheet-metal layout and fabrication, duct design and installation, gutters and flashing, metal roofing, kitchen exhaust, joining methods, blueprints and shop drawings

How to Get Your C-43 Sheet Metal License

Step 1

Qualify

18+ is CSLB's normal applicant path. A minor may qualify only after a court appoints a guardian (BPC §7065.5). You also need a valid SSN/ITIN and 4 full-time-equivalent years of journey-level sheet metal experience within the past 10 years; CSLB prorates part-time work. Up to 3 years may be substituted with approved education or apprenticeship.

Step 2

Apply to CSLB

Submit your application, get fingerprinted, and pay the $450 application fee. Processing times vary; check the CSLB's current processing times.

Step 3

Study & Prepare

Prepare for both exam parts, on your own or with a CSLS exam prep program. 99% of CSLS students pass on their first try, backed by our 100% Money-Back Guarantee.

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Step 4

Pass the Exam

Two parts: Law & Business (115q, 3.5 hrs) + C-43 Trade. Multiple choice, computer-based. CSLS has observed scores of 65% Law & Business / 65% C-43 Trade; CSLB does not publish fixed passing scores and may vary them by exam version.

Step 5

Get Licensed

Post your $25,000 contractor bond, pay the $200 license fee, and receive your C-43 license. You're officially in business.

Step 1

Qualify

Step 2

Apply to CSLB

Submit your application, get fingerprinted, and pay the $450 application fee. Processing times vary; check the CSLB's current processing times.

Step 3

Study & Prepare

Prepare for both exam parts, on your own or with a CSLS exam prep program. 99% of CSLS students pass on their first try, backed by our 100% Money-Back Guarantee.

Compare programs

Step 4

Pass the Exam

Step 5

Get Licensed

Post your $25,000 contractor bond, pay the $200 license fee, and receive your C-43 license. You're officially in business.

Exam Prep Programs

Compare C-43 Sheet Metal Exam Prep Programs

Every program prepares you for the required CSLB exam for C-43 Sheet Metal. Our 99% first-time pass rate is backed by the 100% Money-Back Guarantee on eligible programs.

Feature-by-feature comparison of all four CSLS exam prep programs
Features	Most Popular All-Inclusive C-43 Sheet Metal $1,195.00 Value: $2,500	Live Online C-43 Sheet Metal $695.00 Value: $995	Crash Course C-43 Sheet Metal $495.00 Value: $695	Home Study C-43 Sheet Metal $295.00 Value: $395
Best For	Comprehensive prep with maximum support	Remote learners wanting live instruction	Experienced pros with an exam date soon	Self-directed independent learners
Law & Business Classes	4 Classes + Full-Day Review	4 Live Online + Review	Full-Day Review Only	Not included
Trade Math Training	30-Day Interactive + Review	Online Video Review	14-Day Crash Course	Not included
Test-Taking Skills Seminar	1-Day In-Person	1-Day Online	Not included	Not included
Law & Business Materials	Online; binder add-on available	Online; binder add-on available	Online; binder add-on available	Online; binder add-on available
Trade-Specific Materials	Online; binder add-on available	Online; binder add-on available	Online; binder add-on available	Online; binder add-on available
Study Materials	Full Online Suite	Online Materials + Audio/Video	Online + Audio/Video	Online + Audio
Online Videos	Full Suite: L&B, Trade, H&S, Math	Audio + H&S + Math Videos	Audio + H&S + Math Videos	L&B Audio + H&S Video
Law & Business Practice Exams	6 Months	2 Months	30 Days	30 Days
Trade Practice Exams	6 Months	2 Months	30 Days	30 Days
School Location Access	25+ Locations	25+ Locations	25+ Locations	Self-Study Only
Application Assistance	Preparation & Review	Review Only	Review Only	Not included
Money-Back Guarantee	Included	Included	Included	Not included
Bond Fee Discount	50% off first-year bond, up to $120	Not included	Not included	Not included
Retail Value	$2,500	$995	$695	$395
Choose a program	Get All-Inclusive	Get Live Online	Get Crash Course	Get Home Study

Not sure which fits? Call 800-809-6463. Prices and inclusions are subject to change.

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Common Questions

C-43 Sheet Metal license FAQ

Plan on 2–4 months from application to license-in-hand. That covers CSLB processing (typically 2–4 weeks), scheduling and passing both exams, and posting your $25,000 bond. With CSLS exam prep, most students are exam-ready in 4–6 weeks.

4 full-time-equivalent years of journey-level sheet metal experience within the past 10 years; CSLB prorates part-time work. Qualifying work may be as a journeyperson, foreperson, supervising employee, contractor, or owner-builder. Up to 3 years can be satisfied with approved apprenticeship or technical training. CSLB verifies the experience you claim.

A C-43 (Sheet Metal) contractor fabricates and installs ductwork as a standalone trade, but cannot install the complete HVAC system. A C-20 (HVAC) contractor installs the entire system: furnace, air conditioning, ducts, registers, and controls. Sheet-metal shops often fabricate and hang duct for HVAC contractors; if you want to install whole heating-and-cooling systems, you need the C-20.

The C-43 covers functional sheet metal, duct, gutters, flashing, and metal roofing. The C-23 (Ornamental Metal) covers decorative metalwork in brass, bronze, copper, cast and wrought iron for architectural treatment and ornamentation. If the metal's job is to ventilate or weatherproof, that's C-43; if its job is to decorate, that's C-23.

Budget about $885 minimum before exam prep: $450 for the application (both exams), $200 for initial license issuance, roughly $150 for your first year of $25,000 bond premium, and about $85 for fingerprinting. The bond is a premium you pay, not cash you post.

The C-43 trade exam is computer-based and covers sheet-metal layout and fabrication, duct design, gutters and flashing, metal roofing, kitchen exhaust, and joining methods. You need the current version-specific CSLB passing score to pass. With CSLS exam prep, 99% of students pass on their first attempt, backed by our 100% Money-Back Guarantee.

Yes. Metal roofing systems are explicitly named in both the C-43 and C-39 regulations (CCR §832.43, §832.39), which overlap for this material; CSLB doesn't draw a pre-formed-vs-custom line in the regulation text itself. Custom standing-seam metal roofing is a strong niche for sheet-metal contractors. For the broader range of roofing materials, composition shingle, tile, and membrane, a C-39 (Roofing) license is required.

CSLB evaluates reciprocity case-by-case (BPC §7065.4) and may waive the trade exam if your out-of-state license has been in good standing for the past five years; CSLB names no fixed list of reciprocal states. If you hold an equivalent active sheet-metal license in one of those states, your C-43 trade exam may be waived, but you still must pass the California Law and Business exam and meet all other requirements.

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Become a Licensed C-43 Sheet Metal Contractor

What does a C-43 Sheet Metal contractor do?

Scope of work

High-demand specialties

Important notes

What's on the C-43 Sheet Metal exam?

Law & Business

C-43 Trade Exam

How to Get Your C-43 Sheet Metal License

Qualify

Apply to CSLB

Study & Prepare

Pass the Exam

Get Licensed

Qualify

Apply to CSLB

Study & Prepare

Pass the Exam

Get Licensed

Compare C-43 Sheet Metal Exam Prep Programs

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What our Sheet Metal students say

Try a free C-43 Sheet Metal practice exam

C-43 Sheet Metal license FAQ

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