Most overhangs for 3cm material without a plywood subtop are not to exceed 10-12″. So we’ve put together a few images on are some great ideas on how to solve this issue. The right amount of overhang Island seating generally comes in three heights: table (30 inches), counter (36 inches), and bar (42 inches). Each one requires a different amount of overhang (also called knee space) for diners to sit comfortably. The higher the seating, the less knee space needed, as per these recommendations from the National Kitchen and Bath Association.