“Build-up” in kitchen cabinetry can refer to the hidden strips of wood that create the illusion of a thicker laminated countertop. Typically, prefabricated countertops are only 3/4 inch thick, with a laminate surface glued to a board. To install these countertops, build-up strips of wood are attached to the tops of the base cabinets with screws.
While build-up strips do add support to the countertop at certain points, their primary function is to provide clearance for the overhanging edge of the countertops. This allows cabinet drawers to be opened without interference. Build-up strips are typically included with prefabricated countertops, but they can also be made from scrap plywood or pine.
It’s worth noting that build-up strips may not be necessary for rounded or finished end pieces provided by manufacturers, as these pieces do not overhang the cabinets. However, this only applies when the entire end of the countertop is exposed.