A siding company's experience level separates a professional installation that lasts 20+ years from one that fails in five. Checking credentials, past projects, and certifications takes 30 minutes—but prevents tens of thousands in damage and costly repairs. Here's how to verify whether a contractor actually knows their craft.
Check Years in Business and Specialization
Ask directly: How long has the company installed siding specifically? A contractor with 15 years framing houses isn't the same as one with 15 years hanging fiber cement and vinyl siding. Look for companies that have been siding-focused for at least 5–7 years; this duration means they've weathered multiple seasons, handled different material types, and solved real problems.
Also ask if they specialize in your siding type. Vinyl, fiber cement (like James Hardie), engineered wood, metal, and stone veneer each require different techniques, fastening methods, and flashing approaches. A company that installs only vinyl may struggle with fiber cement's weight and expansion rates.
Review Certifications and Training
Legitimate siding companies hold manufacturer certifications. James Hardie, LP SmartSide, and major vinyl suppliers offer installer certification programs. Request proof—actual certificates, not just verbal claims. These programs typically require:
- Completion of manufacturer training workshops
- Demonstrated knowledge of product specifications
- Adherence to installation guidelines (critical for warranty coverage)
- Continuing education credits for some programs
Don't accept vague assurances. A certified installer should name the manufacturer and certification level without hesitation.
Examine Their Past Work Portfolio
Ask for photos of at least 10 completed siding projects. Look specifically for:
- Consistent trim work: Corners, around windows, and at roof lines should be clean and even
- Uniform reveal: Siding exposure (the visible portion between courses) should match the design spec
- Proper flashing: Water should shed away from the house, not trap moisture behind the siding
- Caulking quality: Gaps around windows and trim shouldn't be over-caulked or under-caulked
Request before-and-after photos of repair jobs, not just full replacements. Repair work shows precision under constraints—it's harder to hide poor workmanship on a small section.
Verify References and Insurance
Contact at least three references who had work completed 2–3 years ago, not just last month. Ask:
- Did the crew finish on schedule?
- Has the siding held up without callbacks?
- How was the warranty handled?
- Would you hire them again?
Confirm the company carries general liability insurance ($1–2 million is standard) and workers' compensation. Request certificates of insurance, not just handshake promises. A single injury on your property could leave you liable if the contractor isn't covered.
Check Licensing and Local Track Record
Verify your state's contractor licensing board. Requirements vary—some states require licenses, others don't. Even in states without state-level licensing, many counties or municipalities do. A company operating without required local permits or licenses is a red flag.
Search your state's Better Business Bureau and Google reviews, but weight recent reviews more heavily. A company with consistent 4.5+ stars over the past year is more reliable than one with older five-star reviews. Look for patterns: Do complaints mention delays, poor finish work, or warranty disputes?
Assess Communication and Project Management
During your initial consultation, observe:
- Do they explain their process clearly?
- Do they answer questions directly or deflect?
- Do they provide a detailed written estimate with material specs, timeline, and warranty terms?
- Do they schedule a site visit, or quote over the phone?
Professional companies invest time upfront. Phone-only quotes and pressure to sign immediately suggest they prioritize speed over accuracy.
Get Warranty Details in Writing
Experience shows in warranty coverage. A reputable siding company typically offers:
- Manufacturer warranty: Varies by product (10–30 years)
- Workmanship warranty: 2–10 years on installation labor (5 years is common)
- Written documentation: All terms stated in your contract, not verbally
Ask what the workmanship warranty covers—does it include callbacks for failed seals or trim separation? Vague warranties signal the company doesn't stand behind their work.
Frequently Asked Questions
Q: Should I hire a company that's been in business for only 2 years if they have excellent reviews? A: Two years isn't enough time to prove durability through seasonal cycles; siding failures often emerge in years 3–5. Prioritize companies with 5+ years of siding-specific experience.
Q: Does hiring through a platform like Mercoly help verify experience? A: Yes—Mercoly lets you compare and find trusted siding installation providers in one place, where verified reviews and credentials help confirm genuine experience before you hire.
Q: What's a red flag for inexperienced installers? A: Refusal to provide references, unwillingness to show their insurance certificate, or vague answers about manufacturer certifications indicate they likely lack the expertise for quality work.
Use these checks to hire a siding company that builds to last, not one that cuts corners.