Originally Posted by HiTech

If you or others live in a climate zone that requires a roof to be sprinkled on sunny, hot days, why not have the roofing material be ceramic tiles... just like it is along the Mediterranian, Mexico and so on?

sunny, hot days you mean everyday

ceramic tiles are good but not always availible and also not always in the budget if you build your house in the first place

what if you rent a house with a contract for 1 a 2 years
if that is the case i am not proposing a new roof to the land lord (and he not to me either)

downside of ceramic tiles is that ones they're heated up they keep their thermal energy also longer so sprinkling those would also do good

espacialy if you don't have cool breazes in a hot climate

insulation of the roof is still a good one

most perfect one is having a roof with a liner panel under it in between them insulation and a grided pipe work pumping cool water through it that comes from a heat pump to heat up your shower water or swimingpool with the energy that it gets from the roof grid

you will be amazed what kind of efficiency you can get

but initial cost to install are not that cheap so if it beneficial depens on the energy cost in the first place
and how much can you do yourself in the instalation of the system (don't forget that your do it self time also has a price)

Robert-Jan