This Architectural Drawing is AutoCAD 2d drawing of Slab thickness of concrete and stub column. Minimum Thickness of Concrete Columns is A column is defined as having a section depth no more than 4 times its width, and the height is a minimum of 3 times the section depth. minimum thickness should not be less than 4.75 inches not forgetting factor of safety. Standard concrete floor slab thickness is residential construction is 4 inches, five to six inches is recommended if the concrete will receive occasional heavy load, such as mortar homes or garbage trucks. For more details and information download the drawing file.