I. How This Project Came About
In the second quarter of this year, we got an email from VdK Architekten, an architecture firm in the Netherlands. They were looking for a material for the façade of a hotel – right in the Rotterdam harbour area, just a few hundred metres from the sea.
Their initial plan was to stick with ThermoWood (heat-treated wood), because the owner loved that natural timber texture. But there was a catch – they'd used it before, and within five years it started showing problems: surface greying, localised cracking, and even mildew on the wall facing the sea. The owner's brief was very clear: "We want the look and feel of wood, but we don't want to repaint it every year."
To be honest, we see this kind of request a lot. Renovations of old buildings in European coastal cities – nine out of ten hit the same wall. We sent them a batch of our co-extruded WPC panel samples, along with our own accelerated ageing test report that simulated marine climate conditions.
Two weeks later, they came back: "We did a 72-hour saltwater immersion test on your samples, and the results were better than we expected. Can you do a custom colour?"
II. What the Real Challenges Were
On the surface, it looked like a simple "swap materials" job, but there were three hurdles.
First hurdle: colour. The designer sent us a colour reference – Pantone 17-4404, a greyish-brown tone they called "North Sea Grey Oak." We didn't have that in our standard colour chart. And they made it clear: if we couldn't match it, all the performance specs wouldn't matter.
Second hurdle: span. The façade required full-length panels of 4.2 metres with no intermediate horizontal support. At that length, ordinary WPC or PVC boards tend to do one thing – bow up in the middle under summer sun, then shrink back in winter, and over time the whole wall looks like a wave. Rotterdam's annual temperature range is roughly from -10°C to +35°C – not extreme, but enough to expose poor-quality boards.
Third hurdle: installation method. The architect insisted: no visible screws on the façade. The fixing had to be completely concealed, and they also wanted the ability to replace individual panels later – because it's a hotel, and you can't tear down the whole wall just to fix one damaged board.
III. Why We Won the Project (Straight-up Parameter Comparison)
At the time, the client had three options on the table: our co-extruded WPC, the originally planned ThermoWood, and a PVC foam board recommended by a local supplier. We put together a table of real test data and sent it to them – no polish, just numbers.
|
Comparison Item |
Our Co-extruded WPC |
ThermoWood |
PVC Foam Board |
|
Core structure |
Wood fibre + HDPE, fully encapsulated outer layer |
Solid wood, heat-treated |
Pure plastic foam |
|
24h water absorption |
≤0.5% |
>12% |
≤0.1% |
|
Flexural strength (MOR) |
≥28 MPa |
≈22 MPa |
≈10 MPa |
|
UV resistance (1500h) |
Grey scale 4-5, barely visible change to the naked eye |
2-3, greys within six months |
3-4, but uneven fading |
|
Fixing method |
Hidden clips, individual panel removable |
Exposed self-tapping screws |
Self-tapping screws, prone to stripping |
|
Maintenance |
None needed |
Annual oiling |
Attracts dust, needs frequent cleaning |
Once the data was laid out, the choice was clear. ThermoWood lost on water absorption and maintenance costs; PVC lost on rigidity and deformation resistance. We weren't the cheapest, but we were the most stable overall. The client's final question before signing off was: "How long does it take for an installer to get used to your hidden clip system?" We said: "Any regular carpenter can install it with a rubber mallet." They didn't hesitate after that.
IV. How We Handled Customisation and Installation
For the colour, our lab went through four rounds of sampling. The first batch was too yellow, the second too grey, the third didn't have natural enough grain depth, and on the fourth the client signed off on the master sample. The whole process took two weeks.
For the installation, we used a two-way pre-stressed clip system – the back of the panel has a dovetail groove, the clips are fixed to the sub-structure, and you just press the panel down until it locks in place. The expansion gaps between panels weren't guessed – we calculated them based on Rotterdam's local annual temperature and humidity data. We mentioned this detail in our proposal, and the architect later wrote to us: "Few suppliers bother to check our local climate data."
The finished façade has zero visible screws. And the added benefit is that if a panel gets damaged later, maintenance staff can remove just that one piece with a special tool, without touching the adjacent panels.
V. What the Client Said
The project was completed at the end of June this year. During installation, Rotterdam had two heavy downpours – we went to site and saw water beading up and rolling off the panels, and the joints were completely dry.
Mr. Dirk van der Meer (project lead, partner at VdK Architekten) sent us a message after the final inspection. I'll quote it directly:
"To be honest, our biggest worry during material selection was that it would 'look like plastic.' But once the panels were up, the whole team breathed a sigh of relief – the wood grain texture and depth were spot on. More importantly, you didn't oversell anything. The data you provided matched what we saw on site. We're already starting the next project in Amsterdam, and I'm specifying your panels directly."
It felt good to hear that, but what really reassured us was his line about "the data matched what we saw" – for an export building-material supplier, that means more than any flowery praise.
VI. Most Frequently Asked Questions About This Project
These aren't made-up questions – they're the ones the client kept coming back to during the project.
FAQ
Q1: Does this panel really need zero maintenance in a coastal environment?
A: Frankly, we don't like to use the word "absolutely." But the fact is, the co-extruded outer layer doesn't absorb water and doesn't provide nutrients for mould, so you don't need to paint or apply preservatives. Regular dust and salt residue wash off with rain. If there's any "maintenance," it's just checking the clips once a year to make sure they're still tight – but that's a very different thing from maintaining timber.
Q2: If I order that custom colour now, can you guarantee it'll match exactly the batch used in the Netherlands?
A: Yes. We keep a master sample on file, and the colour matching is done with a spectrophotometer – not by eye. As long as you specify that colour (close to Pantone 17-4404), we pull the formula from our database, and the batch-to-batch colour difference is kept below ΔE < 1.0 – which is imperceptible to the naked eye.
Q3: Will a 4-metre-long panel really not deform?
A: Under normal use, no. We added a coupling agent in the formulation to strengthen the interface between the wood fibre and HDPE. For the lengths used in this project, we calculated the linear coefficient of thermal expansion at about 1.2mm/m, and the clip system itself allows for expansion and contraction, so the movement is kept within acceptable limits. But we must be clear: if the sub-structure spacing isn't done according to our drawings, no panel – from any supplier – will hold up.
Q4: If I need to replace a panel later, is it a hassle with the hidden clips?
A: Not at all. We have a dedicated removal tool – one person can take a panel off in about five minutes. And the key point is that removal doesn't damage the adjacent panels or clips.
VII. What Backs Up Our Capability on Projects Like This
Here are a few supporting elements – the ones the client paid the most attention to during their qualification review:
VIII. About Us
Haining Longtime Industry Co., Ltd. – we've been in the WPC business for quite a while. We're not the kind of factory that says "we can do everything" but never goes deep. We'd rather spend time studying the climate characteristics of different regions and then fine-tune our formulations accordingly.
If you have a project on your hands and you're torn between wood and plastic, or you can't get the custom colour you want from other suppliers, just reach out. What we can do is put your local climate data alongside our formulation data and see if it's a good fit – if it works, we'll do it; if not, we'll tell you straight.
Technical enquiries and sample requests:
- Website: https://www.longyuanpanels.com/
- Email: ltfriend01@jxlongtime.com.cn
