Cooling down a house in tropical climate

[Fornax]

Originally Posted by Exalta-STA

There is a space but there's nothing there. Just the I-beams holding the bolted down metal roof sheets on top and a gypsum ceiling. Distance from ceiling to the roof are 6 feet to just a couple of feet in some areas...so far, the gypsum has been termite resistant but fails as soon as moisture seeps through the roof.

I think your insulation idea will work because in the 2nd floor in high noon, when you raise your hand above your head, the temperature is wayyy hotter than on eye level.

I agree with Piwoslaw that insulating the roof from the second floor would be a good thing to do. The sun will heat your metal roof which then radiates an enormous amount of heat onto your gypsumboard ceiling.

Do you have access to your 'attic', can you get us a picture?

A fairly easy and cheap way to isolate would be to cover the top of the ceiling with EPS plates. Just put them on the top of the ceiling and cover the entire atticfloor. You can add another layer later. This will isolate your second floor from the hot air in the attic.
Right on top of that you can lay the insulationfoam you found, with the aluminium to the top. That way the aluminium radiates heat away from the floor.

The first thing I'd do though is get those foam/aluminium rolls and hang them underneath the metal roof with the aluminium facing upwards.

How closed is your attic? Is it windy in there during a hurricane?