Stone thickness affects strength, weight, cost and fixing method. Hong Kong most often uses 18 mm, 20 mm and 30 mm: 18 mm for walls, 20 mm for countertops, 30 mm for paving and heavy-duty work. Where weight matters but thin stone does not, honeycomb composite panels are the answer.
Interior walls, feature walls, bathroom walls and lift lobby walls generally use 18 mm. It is lighter, puts less load on the structure and costs less, and works with both dry-hanging and wet fixing. For light troughs or backlit effects, thinner 12 to 15 mm panels can be used.
Kitchen countertops, islands, bathroom vanity tops and washstands normally use 20 mm, which feels substantial and allows many edge profiles. A built-up edge can create a visual thickness of 40 to 60 mm without a proportional increase in weight or cost.
Indoor and outdoor paving, stair treads, bollards, copings and park fixtures needing higher flexural strength use 30 mm or more. Flooring over uneven substrates or with very heavy footfall is also better at 20 to 30 mm.
Honeycomb composite panels bond 3 to 5 mm of stone to an aluminium honeycomb backing, giving about 20 mm total thickness at only 30 to 40 percent of the weight of solid stone. Ideal for cladding, lift cars, large suspended ceilings and additional storeys in older buildings where weight is critical.
20 mm is normally enough in both look and strength; a built-up edge adds visual thickness. 30 mm is used where higher flexural strength is needed for long spans or cantilevers.
Where load capacity is limited, consider honeycomb composite panels at 30 to 40 percent of solid stone weight while keeping the natural stone appearance.
It depends on substrate and footfall. Residential interior paving commonly uses 20 mm; malls, outdoor areas and heavy traffic should use 30 mm or more.