I just finished my first pergola, now I am attempting my first decking. It will be about 12meters by 5 meters, and I will be stumping F7 100x100 treated pine every meter or less. Just wondering if I need to go bigger than 100 x 50 with my bearers since I am stumping so close together. Also do the joists need to go on top of the bearers or can I attach them in between the bearers. A few things that you might need to know are, I plan on putting a boarder around the whole decking so i'll have to double up the timber round the edges, and I only have about 150mm to work with above the posts. Any help would be appreciated, thanks.