I have a shed roof that’s radiating a lot of heat into the interior when it’s hot and sunny.
I’d like to install a radiant barrier of sorts.
The easiest option would be to install some old OSB siding that I have between the rafters on to the underside of the horizontal roof straps. 
Although the roof has a ribbed profile, I’d be creating a checkerboard of dead air.
Should I go the extra length to vent this space?
As always, your thoughts are appreciated.