Missing Gutter Apron
When water flows off the edge of your roof, some of it clings to the underside of the shingles and dribbles toward the fascia. If you have gutters but no gutter apron to stop the water, it will wick behind the gutter.
Eventually the fascia, soffits and even the roof sheathing will rot. You may see water stains below the gutter on the fascia and soffit. This is a sure sign that the gutter apron is missing.