I am planning to build my first 20ft x 20ft deck at the bottom of my garden. Area is pretty flat with a very, very slight slope. I am planning to use a diagnal pattern for the deck boards and obviously need more than one board spanning corner to corner. I know that the joists should be 12 inches apart but do I need to worry about the end of each board attaching to the joists. Do I cut it at a 45 degree angle or just let each board end between joists? Would you recommend a very long 4.8m board or shrter 3.6 meter boards and how should these be staggered to look the best? Thanks for any help. T