How to Vet a Window Installer in Los Angeles (12 Questions to Ask Before You Sign)
LA has hundreds of window contractors. The CSLB licenses them under C-17 (glazing) or B (general building) — both legal for replacement work, but with different knowledge bases on Title 24, seismic anchoring, and historic review. Verify at cslb.ca.gov: active status, $15K bond, workers comp, clean disciplinary record. Then ask the 12 questions below. Any contractor who fumbles more than two of them is not the right hire.
Los Angeles has hundreds of window contractors — licensed general builders, specialty glazing firms, big-box referral networks, and unlicensed crews who show up on Nextdoor with a price that seems too good to be true. Many of them quote similar prices for what looks like similar work. They are not doing similar work.
The CSLB licenses window installers under two classifications: C-17 (glazing) and B (general building). A C-17 license means the contractor passed an exam specifically covering glazing — fenestration products, flashing systems, Title 24 energy compliance, seismic anchorage, and water intrusion. A B-license is a general contractor classification that's legal for standard replacement but carries no glazing-specific training. Most LA window companies are B-licensed. That's not automatically disqualifying — plenty of B-licensed firms run excellent window operations — but it matters when something unusual comes up: an HPOZ review, a Chapter 7A wildfire opening, a seismic anchor failure in a pre-1978 wall, or a Title 24 dispute with the inspector.
The bigger problem isn't the license class — it's contractors operating with an expired license, lapsed workers comp, or an open disciplinary case. In a market where homeowners rarely verify credentials before signing, the exposure is real. This guide gives you the tools to separate the field.
The 12 questions to ask every contractor.
- 11. What's your CSLB license number and class?Any licensed contractor knows their number cold. Write it down, verify at cslb.ca.gov before you go further. The class (B or C-17) tells you how they were trained; the record tells you whether they're current, bonded, and clean.
- 22. Who pulls the permit — you or me?The contractor should pull the permit. If they suggest you pull it as an owner-builder, that shifts all liability to you and means they're avoiding the paper trail. If they say no permit is needed, they're wrong — every LA jurisdiction requires one for window replacement.
- 33. Are your installers W-2 employees or 1099 subs?1099 subs have no loyalty to a contractor's warranty. If a sub botches a flashing and moves on, the contractor can't compel them back. W-2 employees can be recalled to the same job by the same foreman years later. Ask specifically — 'our guys' is not an answer.
- 44. What flashing system do you use on the sill?This question separates experienced window installers from GCs who do windows occasionally. The right answer references self-adhering flashing membrane, back-dam detail, drainage plane integration, and sealant type. A vague answer ('we use flashing tape') or a blank look tells you something important.
- 55. Do you anchor to framing or just foam-and-screw?CRC R613.4 requires mechanical anchors at code-specified spacing for seismic compliance. Foam-and-screw is a common shortcut that passes a visual inspection but fails in seismic loading. About 40% of pre-2010 LA installs are out of code on anchors. Your replacement should bring you current, not perpetuate the problem.
- 66. What's included in the Title 24 compliance package?California requires CF1R/CF2R documentation filed with the permit for replacements that exceed the prescriptive threshold. A blank look means they either don't pull permits or don't understand the compliance chain — both are red flags.
- 77. What's your written change-order policy for rot found on tear-out?Rough-opening rot is found on roughly 20% of our full-frame tear-outs. The only acceptable answer is: we stop work, photograph it, give you a written change order with a price, and wait for your signature before we proceed. Any contractor who says 'we just handle it' or bills it after the fact is a problem.
- 88. Can I see your insurance certificate naming me as additional insured?General liability and workers comp are not optional. Ask for the certificate with your name as additional insured — not a photocopy of the policy page, the actual certificate. If their workers comp is lapsed, their crew is working uninsured on your property. An injury becomes your liability exposure.
- 99. Who is the specific foreman on my job?You want a name, not 'our lead guy.' The foreman owns the flashing, the anchor spacing, and any code call on-site. If they can't name the foreman before you sign, your job goes to whoever's available that morning.
- 1010. Do you have an active CSLB license with no disciplinary history?Ask directly, then verify at cslb.ca.gov. Citations, accusations, and disciplinary actions are all public record. A single old citation isn't necessarily disqualifying if it was resolved — a pattern of accusations or an open complaint is. The CSLB site shows full history, not just current status.
- 1111. What's your warranty — install vs manufacturer?Manufacturer warranty covers the unit — seal failure, hardware, finish. Install warranty covers the labor: flashing, anchors, caulk, water intrusion. These come from different parties and need to be in writing separately. 'Lifetime warranty' with no documentation is a sales line.
- 1212. Have you worked in my specific city or district before?Beverly Hills, Pasadena, Santa Monica, West Hollywood, and Culver City each have their own plan-check process and timeline. HPOZ districts and HOA architectural review add more layers still. A contractor who's never pulled a permit in your city learns on your schedule.
How to verify a CSLB license in five minutes.
Go to cslb.ca.gov, use the 'Check a License' tool, and enter the number the contractor gave you. The record shows: license class (B or C-17), status (active, inactive, expired, suspended), bond amount, workers comp status, and any disciplinary history.
Active status is the baseline. Expired licenses are more common than you'd think — the CSLB renewal cycle is biennial and some contractors let theirs lapse between jobs.
Bond amount. California requires a $15,000 surety bond minimum. The bond lets the Contractors License Fund pay a claim if the contractor defaults or does defective work. If it shows lapsed or below minimum, walk away.
Workers compensation status. If a contractor's workers comp is lapsed, their crew is working uninsured on your property. An injury becomes your liability exposure. The CSLB record shows the current carrier and policy expiration.
Disciplinary history. Scroll all the way down. Citations, accusations, and formal actions are all public. A resolved administrative citation from five years ago isn't necessarily a dealbreaker. An open accusation of fraud or a pattern of complaints within the last three years is. The CSLB complaint process is homeowner-accessible, so the record carries real signal.
Red flags in a quote.
- 1No permit mentionedEvery window replacement in LA requires a permit. If the quote doesn't include permit fees or the contractor says a permit isn't needed, they are either wrong or they're planning to skip it. No-permit installs create a title-transfer problem at sale and leave you with no inspection record if something fails later.
- 2Cash-only discountThe cash-only discount exists because it lets the contractor avoid a paper trail — which is useful if they're unlicensed, uninsured, or planning to skip the permit. A legitimate contractor accepts checks, ACH, or cards. The 'discount' you're being offered is exposure, not savings.
- 3Vague 'energy efficient' language without NFRC numbersTitle 24 compliance is specific: U-factor 0.30 and SHGC 0.23 minimum in LA's climate zones. Any legitimate window quote includes the NFRC-certified U-factor and SHGC for the specified unit. 'Energy efficient double-pane' with no numbers means they haven't specified a window yet, or they're quoting a unit that doesn't meet code.
- 4No written flashing specificationFlashing is how water intrusion is prevented at the window-to-wall interface. It's also the thing most likely to fail quietly over 3–5 years if done incorrectly, causing interior damage that doesn't show up until it's serious. If the quote doesn't specify the flashing system — membrane type, sill detail, drainage plane connection — the spec doesn't exist yet and you have no recourse if it leaks.
- 5No written change-order policy'We'll figure it out if we find rot' is not a policy. The contract should specify in writing that unforeseen conditions found on tear-out are priced as written change orders with a homeowner signature required before work proceeds. Without this, you have no protection against a verbal 'oh by the way, that's going to be another $1,200' at the end of day one.
- 6No named foremanIf you can't get a foreman's name before you sign, you're in a scheduling queue, not a specific crew assignment. The foreman is responsible for the quality of your install. Knowing who they are — and being able to call them back on a warranty claim — is the difference between a real warranty and a phone number that goes to voicemail.
Why W-2 employees matter for a window job.
Most homeowners don't think about the employment status of the crew installing their windows. It matters exactly once — when there's a warranty call.
A 1099 subcontractor is an independent business. They took the job, got paid, and moved on. If they botched the sill flashing and it fails 18 months later, the contractor who sent them cannot legally compel them back. The contractor's only option is to send a different crew to fix work they didn't do — more expensive, and less likely to get it right the first time.
A W-2 employee can be recalled by the company to any job, any time. When we get a warranty call, we send the same person who installed the window. They know the job, the wall, and what they did. The repair is faster and more definitive.
Our entire install crew is W-2. We carry the overhead — payroll taxes, workers comp, benefits — that 1099 operations don't. That shows up in our pricing, and it shows up in our warranty performance. A sub-based operation's lower price reflects a real difference in what happens when something goes wrong.
Understanding who is quoting you — the four models and what each means for your project.
The five things to confirm before you let anyone start demo.
The 12 questions above are for the quote stage. By the time a crew shows up at your door, there are five things to verify before you let them start tearing out a single frame. We've had homeowners call us on install day after a different contractor's crew failed one of these checks — at that point your window of easy exit is closing.
One: check the permit. The permit should be posted or available on-site. The contractor's license number should appear on the permit face. If no permit has been pulled, do not allow demolition to begin — demo without a permit puts you in violation, not them.
Two: confirm the crew lead's name. It should match the foreman named in your contract. If it doesn't, call the company before work begins. Crew assignments can change legitimately, but you should be notified, not surprised.
Three: ask to see the flashing materials. A prepared crew arrives with the self-adhering membrane and the sill cap material pre-staged, not a can of foam and a tube of caulk. The flashing materials tell you immediately whether the spec you were quoted is what's actually going on your house.
Four: verify the window units match the order. Before the old frames come out, check that the replacement units on the truck match the NFRC labels and model numbers in your quote. A field substitution — 'we got these instead, they're basically the same' — is a compliance and quality issue. You ordered specific units with specific NFRC ratings for a reason.
Five: confirm the change-order process before anything starts. Remind the foreman explicitly: 'If you find rot or any unforeseen condition, I need a written quote before you continue.' Get a nod and a name. This one conversation prevents 80% of the mid-job billing disputes we've heard about from homeowners who switched to us for warranty repairs.