Have decided to build a potting shed on the south facing rear of my concrete block garage and would like to know the best way to fix the 3 main battens to the wall. Made one 40 years ago but cannot for the life of me remember how I did it. I want to fix the 2 x 2m uprights and the 2m crossbar each at 4 or 5 points on the wall and would like to know an easy and secure way of doing this.