Is Lightweight Concrete Really Necessary for Countertops?
Normal weight concrete has a cast density that is around 145 pounds per cubic foot (pcf). Lightweight concrete has a cast density of about 115 pcf. A square foot of 1.5″ thick concrete weighs about 18 pounds for normal weight concrete and just under 14.5 pounds for lightweight concrete (a weight savings of less than 4 pounds per square foot). For comparison, 3cm (about 1.25″ thick) granite weighs about 17.5 lbs per square foot. For most kitchen and bathroom cabinets, little or no modifications are necessary to bear the weight of 1.5″ thick normal weight concrete. Lightweight concrete would not convey any significant advantage over normal weight concrete for anything but the largest slabs. However, factors other than slab weight often dictate the maximum slab size and shape. Factors like site access, stairs, corners and general countertop and cabinet configurations, all affect the safe transport, handling and installation of very large slabs. The largest practical slabs may not actually
