Drawing up and costing out the new roof:
To work out the costing for this new roof. Draw a plan of the ridges, gable ends and valleys and transfer accurate sheet measurements and ridge lengths, outside wall spouting measurements etc., onto this plan. Take this plan along to your local roof manufacturer. They will kindly work out for you a list of the sheet lengths and quantity of them you need along with ridge lengths, valleys etc., and the approximate number of roof fixing screws you need. All you have to do is decide on color or plain and profile shape.
Note: Always double check with the supplier the minimum pitch rating for each profile. As if the roof is a very low pitch a low pitch suitable; wide pan wide ribbed profile, may have to be used, even if corrugate was laid there last time around.