Hello everyone, I am Wald, the Head of the Production and Technical Department at Linyi Zhuozhu New Materials Co., Ltd. Recently, a new client asked us a question that deserves a proper answer—and I think many people in the industry can relate to it. The question was simple: “Why did your quotation include more panels than what I calculated from my floor area? My own math gave me a smaller number.”
It’s a fair question. And the answer is something every project owner should understand before placing an order: material loss is real, and failing to account for it can bring your project to a standstill.
The 5–10% Addition: Where Does It Go?
When we calculate the required quantity of sandwich panels, cold room panels, or any building envelope material based on your drawings, we typically add an additional 5% to 10% above the net area measurement. This is not a sales trick. It is an engineering necessity. Here is exactly where that extra material goes.
1. Cutting Loss During Installation
In actual on-site installation, panels must be cut to fit the real dimensions of the building. No matter how precise the drawings are, the physical structure always has slight variations—column positions, openings, corners, and equipment penetrations. Panels are cut to accommodate these, and once a panel is cut, the offcut piece is almost always unusable. You cannot simply join small scraps together to form a continuous wall with proper thermal and structural integrity. Those cut-off sections become waste, and that waste must be accounted for in the original order.
If you order the exact net area with no allowance for cutting, you will inevitably run short. And then you face a painful choice: halt the installation and wait weeks for a supplemental order, or compromise on quality by patching together unsuitable pieces.
2. Transportation and Handling Loss
Panels travel from our factory to your site, and along that journey, they are loaded, unloaded, and sometimes transshipped. Despite our strict packaging standards, edge dents, surface scratches, or corner damage can occasionally occur. A panel with damaged edges may not seal properly at the joints, creating thermal bridges and moisture entry points. Such panels cannot be used in critical areas. Having a 5–10% buffer means your installation team can set aside a few compromised panels and continue working without interruption.
3. Accessories Follow the Same Logic
This principle does not apply only to panels. Accessories such as flashings, eave boxes, external corner profiles, internal corner profiles, and screws all have their own practical loss rates. Flashings need to be lapped and trimmed. Screws can be dropped, lost, or stripped during installation. We calculate the exact count based on standard spacing, then add a corresponding margin for each accessory category. Receiving exactly the right number of screws with no extras is a guaranteed way to have workers searching the floor for dropped fasteners while the clock ticks.
Our Commitment: When the Fault Is Ours, We Take Responsibility
Now, there is an important distinction to make. The 5–10% we add is for normal, unavoidable site loss. But if damage happens because of our own packaging failure, ZHUOZHU has a clear and long-standing policy: we compensate.
If you receive panels that are damaged due to inadequate packaging, simply provide us with photos and videos of the damage. We will either issue a cash refund or supply the replacement panels free of charge in your next order. We do not hide behind fine print. We package our products to rigorous standards precisely to minimize such incidents. But when they do happen, we stand behind our work and make it right.
Why This Matters for Your Project
I have seen projects where the client insisted on ordering exactly the net area, and the result was always the same: a last-minute scramble for extra materials, express shipping costs that far exceeded the cost of a modest overage allowance, and in the worst cases, construction delays that disrupted the entire project schedule.
Adding 5–10% is not about selling more panels. It is about ensuring that your installation team has everything they need on day one to finish the job without interruption. It is the difference between a smooth, professional build and a stressful, piecemeal one.
Let Us Do the Math for You
If you send us your drawings, our engineering team will calculate the net area, apply the appropriate loss factors based on project complexity, and provide a transparent quotation that clearly shows both the net and gross quantities. You will understand exactly where every panel is going—and why.
I’m Wald. At ZHUOZHU, we believe that trust starts with explaining the numbers honestly. If you have a project coming up, reach out, and let’s talk about the real quantities you need to get the job done right.
