How to Verify a Roofer's License in California Before Reroofing

Why License Verification Matters Before Your Reroof

A reroofing project in Altadena can easily run five figures — but the legal line that determines whether your roofer is operating lawfully sits at just $500. Under California law, any roofing job where labor and materials exceed $500 requires a C-39 roofing license, a threshold virtually every reroofing project will cross. California is one of only a handful of states, alongside Florida, Arizona, and Alabama, that requires a statewide roofing license, so this isn't a technicality — it's the baseline for legal work on your home.

The consequences of skipping verification compound quickly. Industry research warns that an unlicensed roof can fail, void manufacturer warranties, trigger insurance disputes, and leave the homeowner with zero recourse. That matters because a new roof is one of the biggest warranty assets you'll own — manufacturer material warranties for asphalt shingles typically run 20 to 30 years, while contractor workmanship warranties range from 2 to 10 years, or up to 25 years through factory-certified installer programs. Improper installation can void all of it.

Then there's the lien risk, which catches homeowners off guard even when they've paid in full. Subcontractors, laborers, and material suppliers can file a mechanics lien against your property if they aren't paid — even if you paid the general contractor. Here's the critical detail: while anyone can record a lien, unlicensed contractors cannot foreclose on one for work valued above $500. But an invalid lien still sits on your title until you take action to remove it, and it can make it difficult or impossible to sell, refinance, or obtain a line of credit on your home.

Verification protects you on several fronts at once:

• Confirms the contractor holds an active C-39 classification through the CSLB's official lookup tool, which includes complaint disclosure
• Verifies the $25,000 contractor's bond and workers' compensation coverage are current
• Confirms the license number appears on all written proposals, as required by Business and Professions Code §7030.5
• Keeps your down payment within the legal cap of $1,000 or 10% of the contract, whichever is less

The whole check takes under two minutes, which is why roofing industry sources call it "the cheapest insurance you'll ever buy." At Altadena ADU Builder, we apply the same standard to every builder we work with — featured contractor JMB Builders LLC holds CSLB #1103479, a license number you can confirm yourself on the state's lookup tool in seconds. Whether you're reroofing a mid-century ranch or planning a garage conversion, that two-minute check is the single highest-leverage step you can take before signing anything.

The C-39 License and the B-License Nuance: What to Look For

Most homeowners assume any contractor with a truck and a ladder can legally replace a roof. In California, that's not the case — roofing is one of the few trades with its own dedicated statewide license classification, and knowing what to look for can save you from voided warranties, insurance disputes, and liens on your title.

The C-39 roofing classification, defined under California Code of Regulations, Title 16, covers contractors who install products and repair surfaces that seal, waterproof, and weatherproof structures — including shingles, shakes, roof tile, slate, metal roofing systems, tar, felt, and urethane foam. Any roofing job where labor and materials exceed $500 legally requires this license, a threshold virtually every reroofing project will exceed.

So what does a legitimate C-39 holder have behind them?

• At least four years of journeyman-level-or-higher roofing experience within the last 10 years, per licensing requirements
• A current $25,000 contractor's bond required to activate the license
• Workers' compensation coverage — notably, C-39 roofing contractors must carry it even if they have no employees
• Active status in the CSLB's free online license lookup, which also discloses complaints

That workers' compensation point matters more than it sounds. Roofing is dangerous work, and if a contractor's crew gets injured on your property without coverage, you could find yourself on the hook. When you check the CSLB profile, confirm the bond is current and workers' comp is on record — if it's missing, walk away.

Now the nuance: the B license. A general contractor holding a B (general building) license can legally perform roofing as part of a larger project, but C-39 is the standard for stand-alone roof work. This distinction comes up constantly in Altadena, where a garage-to-ADU conversion or an Eaton Fire rebuild includes new roofing as one component of a whole-project scope. In that scenario, a B-licensed general contractor is appropriate. If you're hiring someone solely to reroof your house, insist on a dedicated C-39 roofer.

One quick cross-check: California law requires licensed contractors to display their license number on all written advertising and proposals. If the bid on your kitchen table has no license number, that's your first red flag — and a two-minute CSLB lookup is the cheapest insurance you'll ever buy.

At Altadena ADU Builder, we tell homeowners vetting builders for ADU projects to verify classifications the same way — for example, JMB Builders LLC (CSLB #1103479), an Altadena-based general contractor featured in our guide, holds a B license suited to full ADU construction rather than stand-alone roofing. Match the license to the job, and you've eliminated the most common licensing trap before signing anything.

How to Run the CSLB License Check in Under Two Minutes

Two minutes on the CSLB's free lookup tool can save you from a voided roof warranty, an insurance dispute, or an unremovable lien on your home. It's, as one roofing guide puts it, the cheapest insurance you'll ever buy.

Start by getting the license number. California law (Business & Professions Code §7030.5) requires licensed contractors to display their number on all written advertising and proposals, so it should be on the estimate in your hand. If it isn't, that's already a red flag.

Next, run the number through the CSLB's official Check a License tool — the only authoritative source for license verification. Confirm three things on the profile:

• The status reads "Active" with a future expiration date — not Expired, Suspended, or Revoked.
• The classification is C-39 roofing (or a B general building license if roofing is part of a larger project like an ADU or rebuild).
• A current $25,000 contractor's bond and workers' compensation coverage are on record.

On workers' comp, note that C-39 roofing contractors must carry coverage even if they have no employees, per one 2026 guide — and if a crew shows up with no comp on record, walk away, since you could be liable for on-site injuries. For extra assurance, request a Certificate of Insurance directly from the contractor's insurance provider, not the contractor.

Finally, review the complaint disclosure on the profile. A single resolved citation isn't necessarily disqualifying, but multiple open complaints should be.

Then check the contract terms against California law. Down payments are legally capped at $1,000 or 10%, whichever is less — treat a request for more as a serious warning sign, along with same-day signing pressure or a PO box instead of a physical address.

The same diligence applies when roofing is folded into a bigger project. At Altadena ADU Builder, we encourage homeowners to run this check on any contractor they consider — including JMB Builders LLC (CSLB #1103479), an Altadena-based general contractor whose license is publicly verifiable through the same CSLB lookup. Doing so takes less time than reading the proposal itself, and it's the kind of verification that matters just as much for a reroof as for a backyard ADU.

Warranties, Mechanics Liens, and Your Legal Protection

A roof warranty is only as good as the contractor standing behind it — and if that contractor is unlicensed, your protection can evaporate before the first shingle goes on. An unlicensed roof installation can fail, void manufacturer warranties, trigger insurance disputes, and leave the homeowner with zero recourse.

Roofing warranties come in two distinct types, and it pays to know the difference before signing. Manufacturer's warranties cover materials, typically running 20–30 years for asphalt shingles, though many are prorated after a 10–15 year non-prorated period. Workmanship warranties come from the contractor, usually spanning 2–10 years, and can extend up to 25 years through manufacturer-backed certified installer programs, according to warranty industry guidance. Both can be voided by improper installation, unauthorized alterations, or lack of maintenance — which is why the installer matters as much as the shingle.

The lien side catches many homeowners off guard. Even if you pay your general contractor in full, subcontractors, laborers, and material suppliers who weren't paid can still file a mechanics lien against your property. And here's the trap: even an invalid lien stays on your title until you take action to remove it, and an invalid lien can make it difficult or impossible to sell, refinance, or obtain a line of credit on your property, per CSLB's consumer guide.

The good news is that lien validity depends on strict timelines — and homeowners can use them to challenge bad claims. CSLB notes that lien claims are often invalid because the claimant missed required filing deadlines. The three deadlines to check:

• 20 days — Subcontractors and suppliers must serve a Preliminary Notice within 20 days of starting work or delivering materials, or they forfeit lien rights for earlier work.
• 90 days — The lien must be recorded within 90 days of work completion or acceptance.
• 90 more days — Foreclosure must be filed within 90 days of recording, or the lien is invalidated.

There's one more protection built into California law: unlicensed contractors cannot foreclose on a mechanics lien for work valued above $500 — the same threshold that requires a C-39 license in the first place. If you're planning a larger project, like a reroof bundled with an ADU or rebuild, the team at Altadena ADU Builder recommends confirming warranty terms in writing before work begins and tracking who holds lien rights on your project from day one. Courts can also award reasonable attorney fees in lien disputes since the old $2,000 cap was removed in 2012, so challenging an invalid lien is often worth the fight.

Hiring a Licensed Roofer in Altadena: What to Do Next

Verification is only half the job — the other half is putting what you've confirmed into a contract that protects you. Once your roofer's license checks out as Active with the right classification, a few final steps lock in your protection before any shingles come off.

Start with insurance. Ask the contractor for their insurance provider's contact information and request a Certificate of Insurance directly from the insurer, not from the contractor — a paper certificate handed over by the contractor could be outdated or altered. Confirm the policy is active and will remain active for the entire project duration, since a crew without workers' compensation coverage can leave you liable for on-site injuries.

Next, make the contract do the heavy lifting. A complete roofing contract should include:

• The contractor's license number, matching what you verified on the CSLB lookup
• A detailed scope of work, including materials and total cost
• A payment schedule — California caps down payments at $1,000 or 10%, whichever is less
• Change-order procedures and cleanup terms
• Who is responsible for pulling permits

That last item matters more than most homeowners realize. Permits create an official record of the work, and unpermitted roofing can complicate insurance claims and home sales later. California law also requires contractors to display their license number on all written proposals and advertising, so a missing number on a bid is an early red flag.

If you're hiring a general contractor for a larger project — an ADU build, a rebuild, or a whole-home remodel that includes roofing — verify their license number the same way. A B (general building) license allows roofing as part of a larger project, while a standalone re-roof typically requires a C-39 classification. Either way, run the number through the CSLB's free online lookup tool and confirm the status reads Active with a future expiration date. Licensed Altadena builders like JMB Builders LLC (CSLB #1103479), a general contractor working on custom homes, ADUs, and Eaton Fire rebuilds, can be confirmed in seconds on the same lookup.

Finally, protect yourself on the payment side. Even if you pay your general contractor in full, subcontractors and material suppliers can file a mechanics lien against your property if they aren't paid — and an invalid lien can still sit on your title, making it difficult to sell or refinance. Ask for lien releases as payments progress.

If your roofing work is part of a larger project like a backyard ADU, the stakes compound: roofing, framing, and permits all interconnect. At Altadena ADU Builder, we offer a free ADU feasibility consultation with a cost-quiz concept render, so you can see what your project could look like before committing to any contractor.