* These are approximate total job prices based on national average. Costs may vary depending on your region and home’s location, the roof’s slope and number of stories, overall complexity of the roof, the number of layers of the old shingles to be removed and disposed of, type of underlayment and accessories used, and any warranties or .Five factors will impact the cost of your commercial roof replacement. Here’s how to estimate the cost to replace your commercial roof and set your budget..Roof replacement prices in US range from $. $. per sq.ft. for asphalt shingles to $. $. per sq.ft. for metal wood, etc . Your actual cost will vary depending on roof size compl.Roof Rafter Calculator will estimate the Length, Board Size, Quan.y, Cost per board and Total Cost of Lumber! Use the diagram on the right to correctly enter your roof dimensions this will help.