The main factor that may weaken the stability of the roof structure is dampness. On its negative impact it is particularly exposed rafter framing, which deform under impact of water. Therefore is important roof protection against getting in  water into its internal structure.

Typically, investors during the construction of the roof attach great importance both for building materials, as well as careful execution. Unfortunately, later very often they forget about the survey, and any minor defects  commission outsource cheaper and often non-professional roofing companies. This is a big mistake,

Mansard Roof Options & Estimates Remodeling Library. Mansard Roof. A type of hipped roof, a mansard roof is characterized by two slopes on each of its four sides with the lower slope being much steeper, almost a vertical rubber roof, black spots? The RV Forum I

A very important element that must be considered when the roof is projected, is ventilation, allowing drainage of excess dampness from under the roofing.