Contractor adding asbestos certification to an existing license

Become a Licensed ASB Asbestos Certification Contractor

The ASB Asbestos Certification is an endorsement you add to an existing contractor license, required whenever your work involves 100 square feet or more of asbestos-containing material.

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Requirements

Prerequisite: Existing CSLB license in good standing
Experience required: No separate experience requirement
Additional bond: None for the certification itself

About the Exam

Exam format: 1 ASB certification exam
School-observed score: 70%; not published as fixed by CSLB
Application fee: $125

License renews every 2 years. Governing code: B&P §7058.5

About this classification

What does a ASB Asbestos Certification contractor do?

The ASB Asbestos Certification is not a stand-alone license, it is a certification added to an existing contractor license. California requires it before any licensee performs asbestos-related work that involves 100 square feet or more of surface area of asbestos-containing material.

Under Business and Professions Code §7058.5 and Labor Code §6501.8, a licensee must hold the ASB certification to perform asbestos work at or above the 100-square-foot threshold. The certification is earned through a closed-book asbestos certification exam and attaches to whatever license you already hold; it does not authorize contracting on its own.

Official source: CSLB ASB classification · CSLB fee schedule Last reviewed: March 2026

Scope of work

Asbestos-related work involving 100 sq ft or more of ACM
Incidental asbestos removal during a larger licensed project
Asbestos work added to an existing C or general license
Compliance with Cal/OSHA asbestos requirements

Important notes

The ASB is an endorsement, not a license, it attaches to an existing contractor license and does not authorize contracting on its own.
The certification is required for asbestos work involving 100 square feet or more of asbestos-containing material (Labor Code §6501.8).
A C-22 (Asbestos Abatement) license holder does not also need the ASB, the full abatement license already covers asbestos work; ASB is for adding incidental asbestos work to other licenses.
Certain materials are exempt, including asbestos-cement pipe and sheets, vinyl-asbestos floor materials, and asbestos bituminous or resinous materials.
A general building contractor relying on the ASB path (rather than holding the full C-22) must also carry current DOSH registration under Labor Code §6501.5 before contracting asbestos abatement work; ASB certification alone is not sufficient (CCR §833(b)).

The CSLB exam

What's on the ASB Asbestos Certification exam?

The ASB is added to an existing CSLB license after the qualifying individual passes the ASB certification exam. It does not require a new Law & Business exam. CSLB does not publish a fixed question count in the official study guide.

ASB Certification Exam

Adds to your existing license

Multiple choice, closed book
CSLB's official study guide does not publish a fixed question count

How to Add Your ASB Certification

Step 1

Hold a license

Your existing CSLB license must be in good standing before you can add the ASB certification. No separate four-year experience requirement applies.

Step 2

Apply to CSLB

Submit the certification application and pay the $125 application fee. CSLB sends exam-scheduling instructions after accepting it.

Step 3

Study & Prepare

Prepare for the ASB certification exam using the current official CSLB study guide.

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Step 4

Pass the Exam

Pass the ASB certification exam. CSLS has observed a 70% score, but CSLB does not publish a fixed passing score and may vary it by exam version.

Step 5

Add certification

CSLB adds the ASB certification to your existing license. No new contractor bond or initial license fee applies to the certification itself.

Step 1

Hold a license

Your existing CSLB license must be in good standing before you can add the ASB certification. No separate four-year experience requirement applies.

Step 2

Apply to CSLB

Submit the certification application and pay the $125 application fee. CSLB sends exam-scheduling instructions after accepting it.

Step 3

Study & Prepare

Prepare for the ASB certification exam using the current official CSLB study guide.

Compare programs

Step 4

Pass the Exam

Pass the ASB certification exam. CSLS has observed a 70% score, but CSLB does not publish a fixed passing score and may vary it by exam version.

Step 5

Add certification

CSLB adds the ASB certification to your existing license. No new contractor bond or initial license fee applies to the certification itself.

Exam Prep Programs

Compare ASB Asbestos Certification Exam Prep Programs

Every program prepares you for the required CSLB exam for ASB Asbestos Certification. 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 ASB Asbestos Certification $1,195.00 Value: $2,500	Live Online ASB Asbestos Certification $695.00 Value: $995	Crash Course ASB Asbestos Certification $495.00 Value: $695	Home Study ASB Asbestos Certification $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
Exam 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
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
Certification 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

ASB Asbestos Certification license FAQ

No. The ASB Asbestos Certification is an endorsement added to an existing contractor license, not a stand-alone license. It lets a licensee perform asbestos work involving 100 square feet or more of asbestos-containing material, but it does not authorize contracting by itself, you must already hold a contractor license.

You need the ASB whenever your work involves 100 square feet or more of surface area of asbestos-containing material, under Labor Code §6501.8. Below that threshold, the certification is not required. The certification is earned through a closed-book asbestos certification exam and attaches to your existing license.

The C-22 is a full stand-alone contractor license for contractors whose principal business is asbestos abatement. The ASB is a certification added to another license for performing incidental asbestos work over 100 square feet. A C-22 holder does not also need the ASB, the abatement license already covers the work.

The ASB covers asbestos-containing materials in buildings. The HAZ (Hazardous Substance Removal) certification covers contaminated soil, underground storage tanks, and site remediation. ASB is for building asbestos; HAZ is for soil and hazardous-substance work.

The ASB certification exam is closed book and covers planning, containment preparation, abatement methods, documentation, and safety. It is separate from the open-book asbestos examination completed by initial contractor-license applicants. With CSLS exam prep, 99% of students pass their contractor exams on the first attempt, backed by our 100% Money-Back Guarantee.

Yes, all initial contractor license applicants in California take an open-book asbestos exam as part of licensing, regardless of trade. The ASB certification is the separate step you add when you actually plan to perform asbestos work involving 100 square feet or more.

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Become a Licensed ASB Asbestos Certification Contractor

What does a ASB Asbestos Certification contractor do?

Scope of work

Important notes

What's on the ASB Asbestos Certification exam?

ASB Certification Exam

How to Add Your ASB Certification

Hold a license

Apply to CSLB

Study & Prepare

Pass the Exam

Add certification

Hold a license

Apply to CSLB

Study & Prepare

Pass the Exam

Add certification

Compare ASB Asbestos Certification Exam Prep Programs

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What our Asbestos Certification students say

Try a free ASB Asbestos Certification practice exam

ASB Asbestos Certification license FAQ

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