When we visit buildings to inspect the older roofs, more often than not the edge metal has separated from the roof system. The edge metal-to-roof seal is critical in preventing roof leaks along the perimeter walls of the building. The roof-to-edge metal separation also allows water penetration in and behind the fascia boards and exterior stucco walls. Over time the opening can cause wood dry-rot, stucco deterioration and ceiling leaks, especially in upstairs units or rooms. This is the most devastating type of leak because all of the water-flow passes to and over the roof edges.
The typical causes of the edge metal-to-roof separation is usually in the installation. When the roof is applied, the new edge metal flashing needs to be primed with asphalt primer prior to the installation. The primer maximizes the adhesion of the roof to the edge metal. Without the primer, premature roof separation at the roof edge is almost certain. The other cause of the roof edge separation is the fastening method. In most installations the roof nails are too short and too few hold the edge metal in place. Over time, the roof nails begin to pull out creating nail holes in the metal flashing. This allows the edge metal to separate from the roof and move out of place.
Almost every day we see the flat roofs with black roof cement of cap sheet patches applied to the roofs edge in an attempt to stop the roof leaks. Some of the repairs may work on a temporary basis. However, the only permanent solution is to replace the defective edge metal and the strip of roofing that has separated from the edge. The roof deck is now exposed allowing us to find and replace the defective edge metal and the strip of roofing that has separated from the edge. The roof deck is now exposed allowing us to find and replace any wood dry-rot in the deck as a result of the roof edge separation. Now the new roof strip is applied to match the existing roof.