Services

Road construction
Bridge building
Dam construction
Utility installation
Grading & earthwork
Paving
Pipeline installation
Sewer & water systems
Land clearing
Trenching
ASB services
ASB installation
ASB repair
ASB maintenance
ASB consultation
New home construction
Commercial building
Room additions
Remodeling
Structural repairs
Framing
Tenant improvements
Multi-unit construction
Garage construction
ADU construction
Blown-in insulation
Spray foam insulation
Acoustical ceiling installation
Soundproofing
Thermal barriers
Batt insulation
Radiant barrier installation
Fireproofing insulation
Pipe insulation
Energy efficiency upgrades
Boiler installation
Hot water heating systems
Steam fitting
Radiant floor heating
Boiler repair & maintenance
Hydronic heating
Steam pipe installation
Pressure vessel work
Heat exchanger service
Commercial heating systems
Wood framing
Metal framing
Structural framing
Truss installation
Sheathing
Subflooring
Wall framing
Roof framing
Header & beam installation
Seismic retrofitting
Custom cabinets
Cabinet refacing
Built-in shelving
Trim work
Crown molding
Wainscoting
Custom closets
Mantels & fireplace surrounds
Architectural millwork
Door & window casing
Foundations
Driveways
Patios
Sidewalks
Retaining walls
Stamped concrete
Concrete repair
Decorative concrete
Concrete flatwork
Pool decks
Drywall installation
Drywall repair
Texturing
Popcorn ceiling removal
Taping & finishing
Soundproof drywall
Moisture-resistant drywall
Level 5 finish
Drywall hanging
Patch & repair work
C10 services
C10 installation
C10 repair
C10 maintenance
C10 consultation
C12 services
C12 installation
C12 repair
C12 maintenance
C12 consultation
C21 services
C21 installation
C21 repair
C21 maintenance
C21 consultation
C29 services
C29 installation
C29 repair
C29 maintenance
C29 consultation
C33 services
C33 installation
C33 repair
C33 maintenance
C33 consultation
C35 services
C35 installation
C35 repair
C35 maintenance
C35 consultation
C39 services
C39 installation
C39 repair
C39 maintenance
C39 consultation
C50 services
C50 installation
C50 repair
C50 maintenance
C50 consultation
D28 services
D28 installation
D28 repair
D28 maintenance
D28 consultation

Services estimated based on license classification. Claimed businesses can customize their service list.

About the A — General Engineering License

A General Engineering (Class A) license in California authorizes contractors to perform work requiring specialized engineering knowledge and skill. This includes projects like roads, highways, bridges, dams, pipelines, irrigation systems, and utility infrastructure. General Engineering contractors typically work on large-scale civil projects that shape communities and infrastructure. California requires this license for any project where more than two unrelated building trades are used in a fixed work requiring specialized engineering. When hiring a Class A contractor, consumers should verify they have adequate insurance and bonding for the project scope, as these projects often involve significant investment and safety considerations. The CSLB oversees all Class A licensees to ensure public safety and professional standards.

About the ASB — ASB License

A ASB (ASB) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a ASB contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the B — General Building License

A General Building (Class B) license is one of the most common contractor licenses in California. It authorizes the holder to construct, alter, or repair buildings and structures. This includes residential homes, commercial buildings, and industrial facilities. A Class B contractor can use two or more unrelated building trades on a single project, making them ideal for comprehensive construction and renovation work. They often serve as the primary contractor who coordinates subcontractors for specialized trades. When hiring a General Building contractor, homeowners should verify the license is active and in CLEAR status, confirm adequate insurance coverage, and always get a detailed written contract before work begins. General Building contractors must maintain a $25,000 contractor bond and carry workers' compensation insurance if they have employees.

About the C-2 — Insulation & Acoustical License

The C-2 Insulation and Acoustical contractor license covers the installation of insulating and acoustical materials for thermal, sound, and fire protection purposes. This includes installing insulation in walls, attics, and crawl spaces, as well as acoustical ceiling tiles and soundproofing systems. With California's strict energy efficiency requirements (Title 24), C-2 contractors play a vital role in helping homes and businesses meet building codes and reduce energy costs. Proper insulation can significantly lower heating and cooling bills while improving indoor comfort. When hiring a C-2 contractor, ask about R-value recommendations for your climate zone, the types of insulation materials they use, and whether they perform energy audits. Quality insulation work is one of the best investments homeowners can make for long-term energy savings.

About the C-4 — Boiler, Hot Water Heating & Steam Fitting License

The C-4 Boiler, Hot Water Heating and Steam Fitting license authorizes contractors to install, maintain, and repair boilers, hot water heating systems, and steam fitting equipment. This specialized trade requires deep knowledge of pressure systems, safety protocols, and building codes. C-4 contractors work on both residential and commercial projects, from home radiant heating systems to large commercial boiler installations. Given the potential safety hazards of pressurized heating systems, it is critical to hire only licensed professionals for this type of work. California requires regular inspections of commercial boiler systems, making qualified C-4 contractors essential for building owners. When hiring, verify the contractor has experience with your specific type of system and ask about their emergency service availability.

About the C-5 — Framing & Rough Carpentry License

The C-5 Framing and Rough Carpentry license covers the structural skeleton of buildings — the framework that everything else is built upon. C-5 contractors install wood and metal framing, roof trusses, sheathing, subflooring, and other structural components. This is one of the most physically demanding and technically important trades in construction, as the quality of framing directly affects a building's structural integrity and safety. In earthquake-prone California, proper framing techniques and seismic considerations are especially critical. C-5 contractors must understand load calculations, building codes, and engineering specifications. When hiring a framing contractor, look for experience with your project type, verify they follow current seismic codes, and ensure they coordinate well with other trades that will follow their work.

About the C-6 — Cabinet, Millwork & Finish Carpentry License

The C-6 Cabinet, Millwork and Finish Carpentry license covers the fine woodworking and finishing touches that define a home's character. C-6 contractors build and install custom cabinetry, trim work, crown molding, wainscoting, built-in shelving, and other decorative and functional wood elements. This trade requires precision craftsmanship and an eye for detail, as finish carpentry is highly visible and must meet exacting standards. Whether you're renovating a kitchen with custom cabinets or adding architectural details throughout your home, a skilled C-6 contractor can dramatically improve both the appearance and value of your property. When selecting a C-6 contractor, ask to see examples of their previous work, discuss material options and wood species, and get a clear understanding of timelines since custom work often takes longer than standard installations.

About the C-8 — Concrete License

The C-8 Concrete license authorizes contractors to mix, pour, and finish concrete for a wide range of residential and commercial applications. This includes foundations, driveways, patios, sidewalks, retaining walls, and decorative concrete work like stamping and staining. Concrete is one of the most versatile and durable building materials, and proper installation requires significant skill and experience. Factors like mix design, reinforcement, curing conditions, and finishing techniques all affect the final product's strength and appearance. California's seismic requirements add another layer of complexity, particularly for foundation work. When hiring a C-8 contractor, ask about their experience with your specific project type, the concrete mix they recommend, and how they handle weather-related scheduling challenges.

About the C-9 — Drywall License

The C-9 Drywall license covers the installation, taping, texturing, and finishing of drywall (also known as sheetrock or gypsum board). Drywall is the standard interior wall and ceiling surface in modern construction, and the quality of its installation directly affects the appearance of a finished room. C-9 contractors handle everything from hanging sheets to applying final textures and finishes. Different projects require different finish levels, from basic garage walls (Level 1-2) to smooth, paint-ready surfaces (Level 4-5). Specialty applications include moisture-resistant board for bathrooms, fire-rated assemblies, and soundproof installations. When hiring a C-9 contractor, specify the finish level you expect, discuss texture options, and ask about their process for minimizing dust. Quality drywall work is essential for a professional-looking final result.

About the C10 — C10 License

A C10 (C10) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C10 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C12 — C12 License

A C12 (C12) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C12 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C21 — C21 License

A C21 (C21) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C21 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C29 — C29 License

A C29 (C29) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C29 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C33 — C33 License

A C33 (C33) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C33 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C35 — C35 License

A C35 (C35) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C35 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C39 — C39 License

A C39 (C39) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C39 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the C50 — C50 License

A C50 (C50) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a C50 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

About the D28 — D28 License

A D28 (D28) licensed contractor in California is authorized to perform specialized work in their trade area. California's Contractors State License Board (CSLB) requires contractors in this classification to meet education, experience, and examination requirements before receiving their license. When hiring a D28 contractor, always verify their license is active and in CLEAR status, confirm they carry adequate insurance, and get a detailed written contract before work begins. Licensed contractors must maintain a $25,000 contractor bond and comply with all applicable building codes and regulations.

💡 Tips for Hiring a General Engineering Contractor

  1. Get multiple bids for large engineering projects
  2. Verify the contractor carries adequate liability insurance for the project scope
  3. Ask for references from similar completed projects
  4. Ensure all necessary permits are pulled before work begins
  5. Get a detailed written contract with project milestones and payment schedule

✅ Verify This License

Always verify contractor licensing directly with the Contractors State License Board (CSLB) before hiring. You can look up license #92 to confirm it is active and check for any complaints or disciplinary actions.

Check on CSLB.ca.gov →

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Frequently Asked Questions

What does a Class A General Engineering license cover in California?

A Class A license covers projects requiring specialized engineering knowledge including roads, bridges, dams, pipelines, utilities, and other infrastructure work. It does not cover general building construction, which requires a Class B license.

Do I need a licensed General Engineering contractor?

Yes. California law requires any contractor performing engineering work valued at $500 or more to hold a valid CSLB license. Hiring an unlicensed contractor puts you at risk and may void your ability to file complaints with the CSLB.

Do I need a licensed ASB contractor in California?

Yes. California law requires a licensed contractor for any asb work valued at $500 or more. Licensed contractors must pass exams, maintain bonding, and carry insurance. Hiring unlicensed contractors puts you at risk.

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