This hotel near old Bangkok airport had many water leaking problems from the roof.  We waterproofed the roof and  coated it with insulation paint.  The top floor of the hotel became cooler and the water leaks problems were solved.  We did this project  5 years ago in  Dec 2005 and in  March 2010 did some waterproofing  work.  The roof is 1500 square meters large and we first waterproofed the concrete roof area and then used insulation paint to coat on top of the roof.