What CSLB License Classifications Mean: A Complete Guide to All License Types | Expert Guide

When you look up a contractor's license on the California CSLB website, you'll see one or more classification codes. These codes define exactly what type of work the contractor is legally authorized to perform. Understanding classifications helps you hire the right contractor for your specific project.

The Three Main License Categories

California contractor licenses fall into three categories: Class A (General Engineering), Class B (General Building), and Class C (Specialty). Many contractors hold licenses in multiple classifications, giving them authority to perform a broader range of work.

Class A — General Engineering Contractor

A Class A license authorizes contractors to perform projects requiring specialized engineering knowledge and skill. This includes:

Streets, highways, and bridges
Airports and railroads
Dams and reservoirs
Power plants and pipelines
Sewers and water systems
Land leveling and earthmoving
Well drilling

Most residential homeowners won't encounter Class A contractors unless they're dealing with major infrastructure, grading, or utility work. However, if you're building on rural property or dealing with significant site work, you may need a Class A contractor.

Class B — General Building Contractor

The Class B license is the most common license for residential construction and remodeling. A General Building contractor can:

Build or remodel residential and commercial structures
Manage projects involving **two or more unrelated building trades**
Coordinate subcontractors for specialty work
Perform framing, carpentry, and general construction

Important distinction: A B-licensed contractor can self-perform work in two or more trades but must subcontract to properly licensed specialty contractors for certain regulated work (electrical, plumbing, HVAC, etc.). The B license authorizes project management and general construction, not specialty trade work.

If you're doing a room addition, whole-house remodel, or new construction, you'll likely need a B-licensed general contractor to manage the project.

Class C — Specialty Contractors

There are over 40 specialty classifications. Here's every major one explained:

C-2 — Insulation and Acoustical Contractor Installs all types of insulation — thermal, acoustical, and firestopping. This includes blown-in insulation, batt insulation, spray foam, acoustical ceilings, and sound-deadening materials.

When you need this: Attic insulation upgrades, soundproofing, acoustical ceiling installation.

C-4 — Boiler, Hot Water Heating and Steam Fitting Installs, maintains, and repairs boilers, hot water heating systems, and steam fitting. This includes radiant floor heating and hydronic systems.

When you need this: Boiler installation or repair, radiant heating systems.

C-5 — Framing and Rough Carpentry Constructs wood framing for buildings including walls, floors, roofs, and structural components.

When you need this: New construction framing, structural wall modifications, roof framing.

C-6 — Cabinet, Millwork and Finish Carpentry Installs cabinets, built-in furniture, trim, molding, and finish carpentry work.

When you need this: Kitchen cabinet installation, custom built-ins, crown molding, wainscoting.

C-7 — Low Voltage Systems Installs low-voltage systems including fire alarms, security systems, communications wiring, and network cabling.

When you need this: Security system installation, home networking, intercom systems, structured wiring.

C-8 — Concrete Pours and finishes concrete for foundations, slabs, driveways, walkways, retaining walls, and decorative concrete work.

When you need this: Foundation work, driveway replacement, patios, stamped concrete.

C-9 — Drywall Installs, tapes, textures, and finishes drywall (sheetrock/gypsum board).

When you need this: New drywall installation, drywall repair, texturing, popcorn ceiling removal.

C-10 — Electrical Installs, maintains, and repairs electrical systems including wiring, panels, outlets, switches, and lighting. This is one of the most critical specialty licenses — electrical work is dangerous and must be done by licensed professionals.

When you need this: Any electrical work — panel upgrades, rewiring, new circuits, lighting installation, EV charger installation.

C-11 — Elevator Installs, modernizes, and maintains elevators, escalators, and similar conveyance systems.

When you need this: Home elevator installation (increasingly common for aging-in-place).

C-12 — Earthwork and Paving Performs grading, excavation, paving, and earth-moving operations.

When you need this: Driveway paving, grading, excavation for foundations or pools.

C-13 — Fencing Installs all types of fencing including wood, chain-link, vinyl, ornamental iron, and automated gates.

When you need this: New fence installation, fence replacement, automated gate systems.

C-15 — Flooring and Floor Covering Installs all types of flooring including hardwood, laminate, vinyl, carpet, and cork.

When you need this: New flooring installation, hardwood refinishing, carpet replacement.

C-16 — Fire Protection Installs fire sprinkler systems, fire suppression systems, and related fire protection equipment.

When you need this: Fire sprinkler installation (often required in new construction and major remodels).

C-17 — Glazing Installs glass, mirrors, windows (the glass component), shower doors, and glass curtain walls.

When you need this: Window glass replacement, shower door installation, mirror installation.

C-20 — Warm-Air Heating, Ventilating and Air-Conditioning (HVAC) Installs, maintains, and repairs HVAC systems including furnaces, air conditioners, heat pumps, and ventilation systems. One of the most commonly needed specialty licenses in Sacramento.

When you need this: AC replacement, furnace installation, duct work, heat pump installation, ventilation.

C-21 — Building Moving/Demolition Moves structures and performs demolition work.

When you need this: Demolition of structures, building relocation.

C-23 — Ornamental Metal Fabricates and installs ornamental metalwork including railings, gates, and decorative ironwork.

When you need this: Iron railings, decorative gates, metal art installations.

C-27 — Landscaping Designs and installs landscaping including plants, irrigation, hardscape, and outdoor lighting.

When you need this: Landscape design and installation, irrigation systems, outdoor lighting, hardscaping, drainage.

C-29 — Masonry Installs brick, block, stone, and other masonry materials.

When you need this: Brick or stone veneer, block walls, masonry fireplaces, outdoor kitchens.

C-33 — Painting and Decorating Performs interior and exterior painting, staining, wallpapering, and decorative finishes.

When you need this: Interior/exterior painting, wallpaper installation, specialty finishes.

C-34 — Pipeline Installs pipelines for water, gas, sewage, and other fluids (primarily commercial/industrial).

C-35 — Lathing and Plastering Installs lath and plaster, stucco, and EIFS (exterior insulation and finish systems).

When you need this: Stucco repair or installation, plaster work, EIFS installation.

C-36 — Plumbing Installs, maintains, and repairs plumbing systems including water supply, drainage, fixtures, water heaters, and gas piping. Another critical specialty license.

When you need this: Any plumbing work — repiping, fixture installation, water heater replacement, sewer repair, gas lines.

C-38 — Refrigeration Installs and services commercial refrigeration systems.

C-39 — Roofing Installs, repairs, and maintains all types of roofing systems including shingle, tile, metal, flat/low-slope, and coatings.

When you need this: Roof replacement, roof repair, gutter installation (in some cases).

C-42 — Sanitation System Installs septic tanks and alternative sewage disposal systems.

When you need this: Septic system installation or repair (primarily rural properties).

C-43 — Sheet Metal Fabricates and installs sheet metal for HVAC ductwork, gutters, flashing, and architectural elements.

When you need this: Custom ductwork, gutter installation, metal flashing.

C-45 — Electrical Sign Installs electric signs and related wiring.

C-46 — Solar Installs solar energy systems including photovoltaic panels, solar thermal systems, and related electrical work.

When you need this: Solar panel installation, solar water heating.

C-47 — General Manufactured Housing Installs and sets up manufactured homes.

C-50 — Reinforcing Steel Installs reinforcing steel (rebar) for concrete structures.

C-51 — Structural Steel Erects structural steel for buildings and other structures.

C-53 — Swimming Pool Constructs, maintains, and repairs swimming pools, spas, and water features.

When you need this: Pool construction, pool renovation, spa installation.

C-54 — Ceramic and Mosaic Tile Installs ceramic, porcelain, mosaic, and natural stone tile.

When you need this: Bathroom tile, kitchen backsplash, floor tile, shower tile.

C-55 — Water Conditioning Installs water treatment and conditioning equipment.

When you need this: Whole-house water filtration, water softeners.

C-57 — Well Drilling (Water) Drills water wells and installs well pumps.

C-60 — Welding Performs structural and miscellaneous welding.

C-61 — Limited Specialty A catch-all classification with over 30 sub-specialties (D classifications). These cover niche trades like awnings, burial vaults, house moving, tree service, and more.

How to Know Which License You Need

Here's a quick guide:

**General remodel or addition:** B (General Building)
**Electrical work only:** C-10
**Plumbing work only:** C-36
**HVAC work only:** C-20
**Roofing work only:** C-39
**Painting only:** C-33
**Flooring only:** C-15
**Multiple trades:** B (General Building) managing C-licensed subs

Contractors With Multiple Classifications

Many contractors hold licenses in multiple classifications. For example, a general building contractor (B) might also hold a C-33 (Painting) and C-9 (Drywall) license, authorizing them to self-perform that work without subcontracting. More classifications generally means more versatility.

Verify at Sacramento Valley Contractors

Every contractor profile on our site displays their CSLB license classifications so you can quickly confirm they're qualified for your project. Search for contractors by trade on our search page or browse by trade category.