Mature trees, snow and spring thaw
Large trees shade roofs and drop leaves and seeds into valleys and gutters. Shade keeps snow and moisture on the shingles for longer, which encourages moss and granule loss on north-facing slopes. Branches can scrape the surface in wind and break shingle edges.
Through winter, snow builds on low pitches and sits against chimneys and walls. When the first spring thaw hits, water runs under lifted shingles and into any gap in the flashing. Ice at the eaves can back water up under the first course. Clear gutters and a quick walk around the house after the thaw can show wet patches before they spread inside.






