What must be taken into account with any roofing structures and materials
Condensate is formed on the roof in any case: if you use the material of poor thermal conductivity (ondulin, ceramic tiles and others), and if it is a metal roof. Condensate falls on a layer of waterproofing, or without much difficulty with the help of wind enters the room under the roof. Therefore, it is necessary to mount waterproofing on the rafters. We need waterproofing to prevent the wetting with condensate or moisture blown from the sling. It should be borne in mind that even heaters known in the market (isuver, Ursa) lose their properties at the first wet. In contact with moisture, they will be mechanically deformed. Therefore, a gap appears between the rafters and the insulation, the heat goes out into the street.
If you lay the insulation more expensive (steam, Rockwall), it will behave much better. However, despite the fact that such a heater is not afraid of water, at a price it is much more expensive. A double crate should be installed between the waterproofing and the roof. Crate – bars 30×50 mm, lay them along the rafters. Across the counter-rush, it is necessary to lay the crate with the step of this material. With the help of a counter-based circuit, the roofing space as a whole occurs.