Eaves, Rakes, Hips, Ridges, and Valleys
Edge and trim details
At eaves, an eave closure or bird stop closes the gap under the first course, the drip edge sheds water into the gutter, and the overhang is kept within the manufacturer's limit, commonly 1 to 2 in. Rake edges use rake tile, barge boards, or a trim piece fastened mechanically to the barge or fascia, not held by mortar alone.
Hips and ridges
- Hip and ridge tiles are installed over a ridge board or hip line with a starter, then mortar or a dry mechanical system per the manufacturer.
- Mortar mix is typically sand and cement with an additive; mortar is a weather seal, not the only fastener.
- In high-wind areas add screws and mechanical clips, and consider dry ridge and hip systems.
- Ridge ventilation must be balanced with eave intake, and net free area calculation belongs in the layout stage.
Valleys
Tile roofs typically use open valleys: metal at least 24 in. wide, tile cut back to a straight line, and metal exposed so debris and water move freely. Swept or closed valleys are used only where the manufacturer approves the detail; keep fasteners away from the center and never choke the valley with mortar or trimmed pieces.
Worked example. A hip roof on a 30 ft wide building at 6:12, with 45 degree hips in plan. The common run is 15 ft, and the hip multiplier for 6:12 is 1.5, so each hip is about 22.5 ft long. Four hips give 90 linear feet of hip tile, plus 10 percent for cuts, mortar joints, and breakage.
Traps. Using mortar as the fastener; blocking the valley with tile or mortar; overhanging past the gutter line; forgetting the bird stop; sizing ridge vent without checking intake area.