Hi,

I am contemplating replacing the asbestos cement roofing on an outbuilding
(well, old garage behind the newer garage) with polycarbonate sheeting.

The roof is south facing and gets the sun all the year round, so I plan to
trap some in the winter and heat this area above the usual chilly
temperature. I could even channel some heat into the newer garage,
although at the moment it is a fine larder and wine store.

One issue - in the summer it is going to be an oven.
So I would like to have an opening window in the roof, to allow the heat
to escape during the summer days; much like a vent in a greenhouse, or one
of the opening roof lights in loft conversions or single storey pitched
roof extensions (or even conservatories).

So far I haven't found this kind of device in the polycarbonate sheeting
range.
Anyone know of such a thing, and where I might get it?

TIA
Dave R