This occurs when water molecules get trapped underneath between the panel and the insulation or underlayment which can cause the metal to weaken if not coated.
Underside of metal roof.
Place the first screw.
Be sure the larger edge is laid so that the small edge of the next panel will overlap it.
Then as the temperature inside and outside equalise the moisture is released.
The final method of stoppoing a metal roof sweating is to bond an anti condensation layer on to the underside of the roof.
Chris explains that there are two important things to remember with condensation and they may seem somewhat counterintuitive.
Warm air holds more moisture than cold air.
When condensation starts to form on the underside of the roof it is absorbed by the fleece material.
What causes condensation problems on the underside of metal roofs.
No drips are formed.
Align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof.