loft insulation top up

[TonyB]

I want to top my loft insulation, and have bought some rolls of insulation which I will be laying across the joists from one side of roof to the other. I'm not sure what I need to do at the point where the insulation meets up with the sloping roof timbers and felt. I think I'm supposed to leave a small gap so air can circulate ? Is there anything I can attach to the roof timbers to provide that clearance and for the insulation to butt up against ?

[The Natural Philosopher]

sure. tack some hardboard

[Robin]

I ended up using hardboard here as the spacing between the rafters was non-standard (and variable). But if you have a modern loft there are also plastic trays which may be easier (depending on the state of the current insulation) and don't involve any tacking - eg