Almost every insulated aluminum Great Wall roof uses one of two joint systems, and contractors will argue about which is better until the cows come home. The honest answer is that they solve slightly different problems — and picking the wrong one shows up as leaks or extra cost, not on day one, but after the first heavy storm.
Here is the difference in plain terms.
Concealed-fix: the default for most roofs
This is the standard Great Wall profile. The male tongue of one panel slides into the female groove of the next, and the fixing screw goes through a flange hidden inside the joint. The next panel covers it. No screw heads on the surface, nothing for water to track into.
It is fast to lay (a crew does 500–800 m² a day), it looks clean, and for the vast majority of warehouses and factories in the Gulf and Southeast Asia, it is all you need. Purlin spacing up to about 2.5m on a 100mm panel.
Standing seam: when you need more weathertightness
A standing seam raises the joint higher above the panel face and mechanically folds or clips the seam closed. The water path sits well above the roof plane, which matters on low slopes and in driving rain. It also handles thermal movement better on very long panel runs, because the clip lets the panel expand without tearing at the fixing.
You pay for that. Standing seam costs more per square metre and is slower to install. For a flat-ish roof (under 5 degrees), a coastal site with horizontal rain, or panel runs over about 15m, it earns its keep. For a normal-pitch warehouse, it is usually over-specifying.
The quick way to decide
| Your situation | Use |
|---|---|
| Normal warehouse/factory, slope ≥5° | Concealed-fix |
| Low slope (<5°) | Standing seam |
| High wind / coastal driving rain | Standing seam |
| Very long panel runs (>15m) | Standing seam |
| Budget-driven, standard pitch | Concealed-fix |
If you are not sure, tell us your roof slope, the longest panel run, and how close you are to the coast. We will tell you which profile your project actually needs — and we will not push you to the pricier one if concealed-fix does the job.
Get a profile recommendation with your quote
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