There is a excuse to buy a quadcopter. tile inspection.
Danish houses must also have a sub roof / vapor barrier it roofs and exterior walls, which should also catch some fluids the tiles on the roof did not catch.
Actually new houses here get pressure tested to see if then fulfill building codes. as i recall the the loss of air thru vapor barrier on the whole house cant be more than 1 L/s for every SqM
This is tested both by pressurizing the house, but also creating a vacum inside it.
The vapor barrier go up on the inside of insulation,,,,, which are of course a must up here, and as far as i know insulation must be at least 200 mm thick.
The vapor barrier are pretty much just plastic.
The sub roof go up on the outside, just below the tiles or whatever you have for a roof,,,,, you some times install anti flutter springs on this to keep it tight in high winds.
If my memory serve me right every 6 tile in a row on the roof must be secured mechanically / we use a nifty little spring steel contraption that attach to the tile and the horizontal wood they rest on.
Helping my sisters old husband build their roof, we doubled up on those clamps on the tiles, just to make damn sure
I assume you guys down there at least want to keep the heat out of your homes, cold are probably not a issue like up here.
There have been cases where houses have been build too airtight, and so a bathroom ventilator or something can make a vacuum in the house,,,,, this is of course also no good, there have to be a little ventilation.