Fiberglass batts or glass mineral wool metal roof insulation.
Air gap between metal roof and fiberglass batt.
Air gap or air film.
Obviously you need to vent at the eaves and the ridge if an air gap is req.
3 1 4 3 20 6 1 2.
In the winter humidity from the house s interior will get past the insulation and come in contact with the cold roof sheathing where it will condense into water.
Installers say expanding fiberglass assists in sealing air leaks.
Fumes from paper.
Essentially condensation occurs at night when the temperature inside a building is warmer than outside.
That excess moisture ends up as drops of condensation on the roof.
This latter detail reduce the conduction losses and also allowed us to assure that there was no air leakage into the roof cavity this was a cathedral ceiling roof.
Uniform depth as recommended by code or to a higher depth if you wish to achieve better insulation values.
Remember to maintain a minimum 2 gap between the batt and the roof sheathing to allow air flow from eaves into attic space.
As it cools it can t hold as much moisture.
Only if you have a breathable membrane or no membrane felt beneath the tiles can you avoid the air gap.
Picture a cloud of moisture floating overhead between the rafters.
Warm wet air rises and meets the cold roof and cools.
Fill all bays with the loose insulation to a min.
An air space between the insulation and the bottom of the roof sheathing is desirable.
You will need the 50mm air gap if you have felt beneath the tiles.
Both materials make a great physical barrier between the interior building and the metal roof.