How to evaluate the condition (waterproofness, watertightness and air tightness) of your roof?

Here are some precursory signs : Inside: stained ceilings and peeling paints, scaling plaster, lose wallpaper, discoloured spots on walls and ceilings. In the attic: roof support and rafters are darker or wet, damped insulation especially after driving rain. On the roof: for a roof of more than 10 years, granules of protection of the shingle fall apart, fine crack on the surface of shingle, accumulation of granules in the gutter, shingle break, wrinkling of the shingles, buckling and telegraphing of material, building materials dried out quickly and dry caulking.