Thanks, so effectively I have to make the angle of the roof very slightly steeper to allow for it dropping under its self-weight and after the roof sheeting has been installed?
Hi, I am designing a portal frame and understand that the dead load and self-weight deflection of the rafters can be ignored as this can be taken out by the steel frame fabricators 'pre-setting' the rafter. How is this done, what does pre-setting involve? Is it cambering the rafter?
