Step 3: Add the cross braces for the floor and top
2. Use 4 1x4s to connect the top 2x4s. This will give the whole frame additional rigidity. These will be laid flat across the top 2x4s.
3. Use a 2x4 down the middle of the top side of these 1x4s. The 2x4 will be oriented vertically. This will give minor slope to the roof. The roof plywood sheets will be attached to this 2x4.