I have add on to my house that is similar to a sun room. I would like
to keep it cooler since it is open to the living room and kitchen. It
has a shallow roof just big enough for r 19 insulation. What I would
like to do is build a second roof on top of the original and about 12
inches high for air flow. I may combine it with a radient barrier.

Has anyone out there done this before? Could I make it with some sort
of removable (for winters) awning material or build it strong with
wood and shingle. I am worried about the second roofs load on the sun
room room.

For the record I live in Austin TX