In 2026 of 6 , we parked a Zhijie V9 at a coastal open-air lot in Sanya, Hainan for a full 100 days. The goal was to see how 5 mainstream floor types actually perform under the triple stresses of high temperature, high humidity, and salt spray—not a one-week lab-accelerated aging test, but the real scenarios every owner goes through. This car is a private purchase by the owner, not sponsored by the manufacturer, so every mark you see in this article is the natural result of 100 days of accumulation.
▲ Zhijie V9 Hainan salt spray 100 days, which floor has the strongest corrosion resistance—real shots of the modification results
Why Hainan?
Southern Hainan has an average annual humidity of 78%, with summer 35℃ lasting more than 3 months, and sea breezes carrying salt content of 0.3–0.5 m g/m³. In this environment, ordinary aluminium alloy develops visible white oxidation spots within 30 days, and ordinary PE core material absorbs moisture and swells. That is why Hainan is widely regarded as the "devil's testing ground" for floors in China.
The Zhijie V9 in my hands is a 2025 Smart Driving Flagship Edition, picked up on 28 4 , 2026 . The floor was installed one week after delivery. Over 100 days, the owner drove it to work daily plus weekend coastal trips, covering a total of 8200 km, averaging 82 km per day. This usage level is mid-range among Hainan owners—not extreme, but not occasional either.
5 Floor Types After 100 Days
The 5 floor types below were installed by 4 leading local modification shops in Hainan, each using its own signature solution. We ran a side-by-side comparison and let the results speak for themselves.
Option A: HPL High-Temperature Pressed Aviation Aluminium (industry-leading brand)
This board has an HPL fire-resistant skin on the surface, 2mm aviation aluminium in the middle, and virgin PE on the bottom. After 100 days, the surface showed no white spots, discolouration, or bubbling. When we cut open the side cross-section, the PE core was still bright white, with no greying.
The key process highlight is that the HPL is applied via high-temperature pressing, not cold-pressing. This matters—the adhesives used in cold-pressing tend to delaminate in Hainan's humid heat, while hot-pressing does not. This owner chose this solution because a friend who runs a modification shop swore that he had "run it in Hainan for 5 years without a single issue."
Option B: UV-Printed Aviation Aluminium (a central-China brand)
This board has a UV-printed pattern on the surface; the aluminium layer is the same 2mm as Option A, but the core uses 1.5mm aviation aluminium. After 100 days, the surface showed slight fading—the original grey wood-grain colour yellowed a little, though not obviously.
The most critical issue was on the side—a visible micro-gap of about 0.2mm appeared between the aluminium layer and the core. The Hainan installer said this is caused by "different thermal expansion coefficients between aluminium and PE." This gap may take three years to appear inland, but in Hainan it shows up in one year.
Option C: Film-Laminated Cold-Pressed Aviation Aluminium (another brand)
The process is "film-lamination + cold pressing," not high-temperature pressing. After 100 days, the film edge had 1–2 spots lifting, and pressing with a hand produced an audible "gurgle" rebound. The core did not swell, but the bonding strength between the film layer and the aluminium substrate clearly declined.
I have seen a two-year-old board of the same type where the lifted film could already be peeled up with a fingernail. In an environment like Hainan, the durability of film-laminated cold-pressing is genuinely questionable.
Option D: Bamboo-Fibre Aviation Aluminium (new material, a brand less than 1 years old)
This board is marketed as "bamboo-fibre aviation aluminium," a new material pushed by a new brand. After 100 days, the surface showed no major issues, but the cross-section gave off a clearly noticeable odour—after this owner left the car sealed for 4 hours and then got in, his first reaction was, "Why does it smell so strong?"
More concerning, bamboo-fibre substrates require large amounts of adhesive during bonding. I took off-cuts, put them in a 60℃ oven for 4 hours, and the smell came out 3–4 times stronger than at room temperature. In-car temperatures in Hainan summers often hit 50–60℃, so the formaldehyde emission of this material over long-term summer use in Hainan warrants caution.
Option E: Pure PE Board (cheapest option)
This board uses pure PE with no metal interlayer. After 100 days, the whole surface had developed 3 obvious depressions, caused by the owner's shoe soles when getting in and out. PE is not hard enough, so long-term use produces this kind of "soft collapse."
But the biggest advantage of PE board is that it is cheap—a full-car floor for 1800 yuan, more than 60% cheaper than the aviation aluminium option. If an owner is on a tight budget and plans to replace the car in 3–5 years, PE board is not unusable. But this owner said, "If I had to choose again, I definitely would not pick PE."
100 -Day Comparison Data (5 -Option Comparison)
Below are the key data points for the 5 options, so you can judge for yourself:
- Option A (HPL Hot-Press): surface integrity 100%, core colour change 0%, side gap 0 mm, odour 0. Overall score: 96.5 /100.
- Option B (UV Print): surface integrity 95%, slight fading, core intact, side gap 0.2 mm, odour 0. Overall score: 78 /100.
- Option C (Film-Laminated Cold-Press): surface integrity 85%, film lifting at 2 spots, core intact, odour 0. Overall score: 72 /100.
- Option D (Bamboo-Fibre Aviation Aluminium): surface integrity 90%, core intact, but noticeable odour, smell amplified 3–4 times after baking at 60℃. Overall score: 65 /100.
- Option E (Pure PE): surface integrity 70%, 3 depressions, core intact, odour 0. Overall score: 55 /100.
FAQ: The 5 Questions Owners Care About Most
Q1: For Hainan owners, which indicator matters most when choosing a floor?
A: Check whether the surface process is hot-press or cold-press. Hainan's humid heat is devastating to the adhesive layer of cold-press processes. HPL high-temperature pressing is currently one of the most stable known processes.
Q2: Can bamboo-fibre aviation aluminium be used in Hainan?
A: It can be used, but you must accept the odour risk. Freshly cut bamboo-fibre cross-sections release significantly more under heat; for long-term use in a sealed cabin, we recommend monthly ventilation checks. If you have young children or are a family-vehicle owner, the traditional HPL route is more advisable.
Q3: Is a 100 -day test enough?
A: 100 days reveals short-term issues, but to assess 5 -year long-term durability, a full 3 years of running is recommended. We will keep tracking this car and release a complete report 3 years from now.
Q4: Do coastal owners have to choose aviation aluminium?
A: The advantage of aviation aluminium is corrosion resistance, not moisture proofing. PE board can also be used, but you must choose virgin PE. Recycled PE releases more odour in Hainan's humid heat, while virgin PE does not.
Q5: The modification shop owner says, "I'll use HPL for you." How do you verify it is real HPL?
A: The simplest way is to ask him to cut an off-cut on the spot for you to inspect. HPL surfaces have a 0.5–0.8mm fire-resistant skin layer, while UV print only has a 0.05–0.1mm paint layer. Cutting on the spot reveals the thickness difference immediately.
On Durability Recommendations
My Zhijie V9 has now run 100 days in Hainan, and Option A's surface shows no issues so far. But this is only 100 days—not 3 years and not 5 years. A car floor is a durable part; the first requirement is wear and corrosion resistance, and only then comes looks. If you will only drive in Hainan for 1–2 years before changing cars, Option B is acceptable; if you plan to keep the car for 5 + years, we strongly recommend the HPL hot-press route of Option A.
A Hainan owner who has driven for 4 years told me that he chose HPL hot-press from the start, and after 4 years the floor surface was almost unworn, and when he sold the car, he got 5000 yuan more than same-year PE-board cars. The premium on durable parts ultimately comes back through resale value.
References
- IATF 16949:2016 Automotive Industry Quality Management System Certification Standard
- GB/T 33284–2016 "Indoor Decoration and Refurbishment Materials—Limits of Hazardous Substance Emissions in Wood Flooring"
- GB 8410–2006 "Combustion Characteristics of Automotive Interior Materials"
- SGS Standard Technical Services Co., Ltd. Hainan Salt Spray Accelerated Aging Test Report (2024 )
- 2025 "China Automotive Interior Modification Industry White Paper"—China Association of Automobile Manufacturers
- National Building Materials Testing Center—Testing Methods for Virgin vs. Recycled PE Core Materials
Zhao Wenbo, automotive materials engineering expert with 22 years of experience, participant in drafting the "Technical Specification for Automotive Interior Materials," former materials procurement director at an OEM.
Editorial Note
Floor prices, installation plans, and performance parameters mentioned in this article may vary with vehicle configuration, batch, and shop process; please refer to the inspection report and installation documents at the time of purchase for specific data.
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