C-2 Insulation and Acoustical Contractor license in California

Updated November 1, 2026 · Official name from CSLB's classification list

• 1,210licenses hold C-2
• 97.2%Clear (CA addresses)
• 22.4%workers' comp exempt (all: 49.6%)
• 100%contractor's bond on file
• 17.7 yrsmedian time licensed
• 75%businesses, not sole owners

A C-2 contractor installs insulating materials and preformed acoustical products, for temperature control, sound control or both. That covers blown-in attic insulation, batts in walls and floors, and acoustical ceiling panels in offices and schools.

CSLB folded two old subcategories into this class: D-2 Asbestos Fabrication and D-17 Industrial Insulation. So a C-2 can also insulate pipes, tanks and equipment in industrial settings. Homeowners mostly hire C-2 contractors when an attic is under-insulated or a home theater needs quieter walls.

Typical work under C-2

• Blown cellulose or fiberglass in attics
• Batt insulation in walls, crawlspaces and floors
• Spray foam insulation
• Acoustical ceiling panels and sound-control wall materials
• Insulation on pipes, ducts and industrial equipment

Work that needs a different license

• Removing old insulation that may contain asbestos: C-22 Asbestos Abatement
• Replacing ductwork in the attic: C-20 HVAC or C-43 Sheet Metal
• Hanging drywall over new wall insulation: C-9 Drywall

Tips before hiring

• Ask the bid to state the R-value and depth for each area, so you can compare quotes on the same terms.
• In an older home, ask whether the existing material will be tested before anyone disturbs it.
• For an attic job, ask how the crew will keep insulation clear of recessed lights, vents and the furnace flue.
• If the business is an LLC, check that its liability insurance and worker bond appear on the license record.

Where C-2 contractors are

The cities with the most C-2 license holders in CSLB's current file:

1. Insulation Contractors in Fresno: 35
2. Insulation Contractors in San Diego: 30
3. Insulation Contractors in Anaheim: 26
4. Insulation Contractors in Sacramento: 26
5. Insulation Contractors in Riverside: 25
6. Insulation Contractors in Bakersfield: 24
7. Insulation Contractors in San Jose: 23
8. Santa Rosa: 19
9. Hayward: 17
10. Concord: 15

All insulation contractors lists

Cities with at least 20 C-2 license holders, largest first:

• Fresno (35)
• San Diego (30)
• Anaheim (26)
• Sacramento (26)
• Riverside (25)
• Bakersfield (24)
• San Jose (23)

How to verify a C-2 license

1. Search the business or license number here and confirm C-2 is listed on the profile.
2. Check the same number on CSLB's Instant License Check.
3. Read our full guide to checking a contractor license.

Related license types

• C-9 Drywall Contractor
• C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor
• C-22 Asbestos Abatement Contractor
• C-61 Limited Specialty

Source: CSLB public data · Updated November 1, 2026 Status can change at any time. Verify on CSLB's Instant License Check.

More license types: ← B-2 Residential Remodeling Contractor · C-4 Boiler, Hot Water Heating and Steam Fitting Contractor →