Setting stack layers isn't just dividing ceiling height by cage height. Most cages are mesh-panel structures; when stacking, a forklift must lift the upper cage above the lower one and lower it down, and this lift height is often larger than the theoretical ceiling-divided-by-layers value.
Key calculation points: first confirm the clearance between the mast's highest point under full lift and the roof beam — usually leave 0.5 m or more. Then measure the distance from the top of the uppermost cage to fire sprinklers, light fixtures and roof beams, and leave operating margin as well; safety comes first.
Take the common 1.0 m tall cage in a 4.5 m clear-height warehouse: after deducting forklift lift clearance and safety gaps, you can actually stack about 3 layers. Below 3 m clear height, usually only 2 layers are possible. Blindly stacking by the theoretical value means the forklift can't fit at best, or hits a roof beam and causes an accident at worst.
Beyond ceiling height, check whether the bottom cage's stacking load can take it — the higher the layers, the higher the bottom cage's load requirement; the two must be calculated together. Nanjing Tongnuo can produce a stacking plan and cage-type recommendation based on your warehouse's measured dimensions, having served over 1,000 customers, and produces only after the plan is approved.
When selecting stackable cages, give the maker three numbers — warehouse clear height, forklift model and safety gap; that pins down size and load far better than just saying 'we want four layers', and avoids cages that won't fit or can't be stacked on arrival.