On the shoreline the edge is the hardest working part of the roof, and it is the part most often specified as an afterthought.
Start at the perimeter
The roof edge carries the highest uplift pressure on any building, and a waterfront site raises that load year round. Drip edge, starter courses, fascia fastening, and clean transitions decide performance long before the field of the roof matters.
Plan for water moving sideways
Open water pushes rain horizontally rather than straight down. Valleys, dormer cheeks, wall flashing, and roof-to-siding transitions all need generous overlaps and durable underlayment to stay watertight under that load.
Match the material to the exposure
Standing seam metal, copper, slate, and composite each behave differently on an exposed shoreline. Aluminium resists salt and humidity better than steel; slate and composite carry weight and impact differently. The site should drive the specification, not the catalogue.