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,

`Nora_to_Toki_no_Koubou_Kiri_no_Mori_no_Majo_JPN_NDS. Nora_to_Toki_no_Koubou_Kiri_no_Mori_no_Majo_JPN_NDSBAHAMUT.; サイズ 212.9; 日付 20110723 011607; 機種 Nintendo DS; ダウンロード回数 9461回 Of Sunnybrook Farm Project Gutenberg Project Gutenberg s of Sunnybrook Farm, by Douglas Wiin This eBook is for the use of anyone anywhere

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