Home » drywall-t-square » What are drywall squares? What are drywall squares? Chris 29th February 2020 24 Views SaveSavedRemoved 0 What are drywall squares? Shop for Drywall Tools A drywall square is a larger form of the T-square, specially designed for cutting large sheets of material such as plasterboard. It has two rulers. The top ruler, being shorter, runs along the edge of the board.