Insulation contractor installing batt insulation in a wall

Become a Licensed C-2 Insulation & Acoustical Contractor

The C-2 Insulation and Acoustical license covers thermal and sound control, batt, blown-in, and spray-foam insulation, plus acoustical ceiling systems.

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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 / 68% Trade; not published as fixed by CSLB
Application fee: $450

License renews every 2 years. Governing code: CCR §832.02

About this classification

What does a C-2 Insulation & Acoustical contractor do?

Under California Code of Regulations Title 16, §832.02, a C-2 Insulation and Acoustical Contractor "installs any insulating media and preformed architectural acoustical materials for the purpose of temperature and/or sound control." It is the trade dedicated to keeping buildings warm, cool, and quiet.

The C-2 is the insulation and acoustical specialist's license. C-2 contractors install thermal insulation in all its forms, batt, blown-in, spray-foam, and rigid, along with acoustic ceiling tile and the duct-insulation wraps that control temperature and sound.

The scope spans both energy efficiency and sound control, covering preformed architectural acoustical materials as well as the full range of insulating media used in residential, commercial, and industrial buildings.

Official source: CSLB C-2 classification · CSLB fee schedule Last reviewed: March 2026

Scope of work

Batt and roll insulation
Blown-in and loose-fill insulation
Spray-foam insulation
Rigid board insulation
Acoustic ceiling tile and panels
Duct-insulation wraps
Sound-control acoustical materials
Thermal insulation for walls, attics, and floors

High-demand specialties

Energy Efficiency & Weatherization, Title 24 energy-code work and retrofits across California
Spray Foam, High-performance air-sealing insulation in growing demand
Acoustical Ceilings, Sound control for offices, schools, and commercial space

Important notes

C-2 vs. C-20: the C-2 installs insulating media and acoustical materials for temperature and sound control; the C-20 (HVAC) covers the heating and air-conditioning equipment and ductwork. Insulation and acoustic tile are C-2; the HVAC system is C-20.
A C-2 contractor can install duct-insulation wraps, but cannot fabricate or install the ductwork or HVAC equipment itself, that requires the C-20 or C-43.
A C-2 contractor cannot install drywall (C-9) or apply wet plaster (C-35); acoustical tile and insulation are its distinct scope.
Projects over $1,000 (labor and materials combined) require a license. Workers' compensation coverage is required once you have employees; sole owners with no employees may file a no-employee exemption (BPC §7125(b)).
The former D-17 Industrial Insulation classification was absorbed into the C-2, which now covers both building and industrial insulation.

The CSLB exam

What's on the C-2 Insulation & Acoustical exam?

California requires you to pass a two-part CSLB exam: the Law & Business exam (the same for every classification) and the C-2 Insulation & Acoustical trade exam. CSLS has observed scores of 65% for Law & Business and 68% for the C-2 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-2 Trade Exam

Insulation & Acoustical-specific

about 115 questions, multiple choice, computer-based
3.5 hours allotted
Topics: insulation materials and R-values, batt and blown-in and spray-foam installation, acoustical ceiling systems, duct insulation, energy codes (Title 24), blueprint reading

How to Get Your C-2 Insulation & Acoustical 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 insulation and acoustical installation 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-2 Trade. Multiple choice, computer-based. CSLS has observed scores of 65% Law & Business / 68% C-2 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-2 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-2 license. You're officially in business.

Exam Prep Programs

Compare C-2 Insulation & Acoustical Exam Prep Programs

Every program prepares you for the required CSLB exam for C-2 Insulation & Acoustical. 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-2 Insulation & Acoustical $1,195.00 Value: $2,500	Live Online C-2 Insulation & Acoustical $695.00 Value: $995	Crash Course C-2 Insulation & Acoustical $495.00 Value: $695	Home Study C-2 Insulation & Acoustical $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-2 Insulation & Acoustical license FAQ

The C-2 (Insulation and Acoustical) installs insulating media and acoustical materials for temperature and sound control, batt, blown-in, spray-foam, and rigid insulation, plus acoustic ceiling tile and duct-insulation wraps. The C-20 (HVAC) installs the heating, ventilating, and air-conditioning equipment and ductwork. Insulation and acoustic tile are C-2; the HVAC system itself is C-20.

A C-2 contractor installs thermal insulation, batt, blown-in, spray-foam, and rigid board, in walls, attics, and floors, along with acoustic ceiling tile, sound-control materials, and duct-insulation wraps. The trade covers both temperature control (energy efficiency) and sound control.

Yes. Spray-foam insulation is within the C-2 scope, along with batt, blown-in, and rigid board insulation. Spray foam is one of the higher-demand niches under the C-2 because of its air-sealing and energy-efficiency performance under California's Title 24 energy code.

A C-2 contractor can install duct-insulation wraps, but not the ductwork or HVAC equipment itself. Fabricating and installing ductwork falls under the C-43 (Sheet Metal) or C-20 (HVAC) classification. The C-2 covers the insulation around ducts, not the ducts themselves.

4 full-time-equivalent years of journey-level insulation and acoustical installation 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 three years can be satisfied with approved technical training, apprenticeship, or education. CSLB requires you to document and verify this experience.

From application to license-in-hand, the path usually runs 2–4 months, CSLB application processing (typically 2–4 weeks), exam scheduling, passing both exams, and posting your $25,000 bond. With CSLS exam prep, most insulation pros are exam-ready in 4–6 weeks.

The C-2 trade exam covers insulation materials and R-values, batt, blown-in, and spray-foam installation, acoustical ceiling systems, duct insulation, and energy codes. 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.

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Become a Licensed C-2 Insulation & Acoustical Contractor

What does a C-2 Insulation & Acoustical contractor do?

Scope of work

High-demand specialties

Important notes

What's on the C-2 Insulation & Acoustical exam?

Law & Business

C-2 Trade Exam

How to Get Your C-2 Insulation & Acoustical 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-2 Insulation & Acoustical Exam Prep Programs

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What our Insulation & Acoustical students say

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C-2 Insulation & Acoustical license FAQ

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