We have recently moved into a house in Australia with a tin roof. There is a layer of 5cm batts on the rafters in the roof space, but the temp is 10-15 degrees C higher up there than in the house (with all the windows and doors open). I don't want to get air-conditioning, is there another way to insulate the roof and cool the house?
put insulation above the ceiling (not on the rafters) and add vents on each side of the attic....
like they said ventilation is the answer... you allready have a radiant barrier ( metal roof ), now get the heat out. a rigge vent would be best with plent of open soffit all the way around the perimeter. if you're in a dry climate, a humidifier will work as well as an a/c, but much cheaper! give measurments in feet & inches... what do you thing, some one from france is going to help you?
The attic will always be warmer than the house--that's the point of the insulation--to separate the heat in the attic from the cooler air in the house. However, to improve it even more, add insulation on the ceiling joists (not the roof rafters). Make sure there is plentiful ventilation in your attic (when the wind blows, you should feel it blowing inside your attic). Eave vents, ridge vents--it doesn't really matter which ones you use--but you have to have enough for the air to really flow.
go and buy a roof whirly for every 10mtr. square ,, if you don't want to spend the money then try to put in more vents in the eves so more air can be drawn into the roof space... another thing that I have always thought of doing myself is to get shade cloth and cover over the roof but not touching the tin. Maybe a blind type of thing, where you could roll it up in winter when you want to get the roof hotter. .. anyhow I think whatever you do to redude the heat you must be able to retain the heat in winter if you do not want to use a heater as well... cool luck ''lol"
