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,

West Virginia MINE DISASTERS Note Fromto 1961, accidents fatally injuring five or more employees were classed as disasters. Fromto date, accidents fatally injuring three or more. Construction Members Lethbridge Construction Association. The following is a list of members for the Lethbridge Construction Association for 2015. Scroll

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