What makes box gutters different
Unlike a standard hanging gutter, a box gutter is a trough built into the roof, often between two roof slopes or behind a parapet — its lead lining is the only thing keeping it watertight.
Why they're higher risk
Because a box gutter often can't be seen from the ground and sits within the roof structure, a leak here can go unnoticed for longer and cause more hidden damage before it's found.
Relining and repair
Depending on condition, a box gutter can sometimes be repaired locally, but a gutter with widespread wear is usually better relined completely in fresh lead, properly falls-checked to drain correctly.