We have a two-story porch with four columns on the main floor and four columns on the 2nd floor. They are made out of wood and are splitting. (100 yr old house.) We need to replace them and need to do it ourselves but we want to do it safely and correctly. How many braces do we need. The span dimension of the porch is 10ft x 18ft. and the columns are located 2 on each corner. Need some suggestions Can anyone help?