I am about to build a house in Phuket, part of which will have a flat roof in order to maintain views. Really looking for a method to keep the part of the house with a flat roof cool.

Will a roof garden help?

What about a double roof with some form of air flow?

Any ideas welcome and appreciated.

Same as you would with any roof space. Leave a gap between the ceiling and roof and insulate.

A roof over the roof, or any type of shade, will definitely be the best first line of defence.

If thinking about planting a garden up there, you'll want to check with your engineer first to see what weight loading it was designed for though...