Tile Layout, Attachment, and Fastening
Setting the layout
Tile length equals exposure plus headlap, and the headlap must meet the manufacturer's minimum, commonly about 3 in. for field tile. Establish a level starter course at the eave, snap horizontal chalk lines at the gauge, and snap vertical lines to control coursing. Check the roof plane for square by comparing diagonals before any tile goes down, and split the layout so rake cuts are equal rather than leaving a sliver on one side. Stagger the vertical joints between courses and engage the side locks on interlocking tile.
Fastening rules
- Two corrosion-resistant fasteners per tile unless the manufacturer or high-wind design requires more; copper, stainless, or hot-dip galvanized fasteners near the coast.
- Place nails in the headlap zone so the following two courses cover them; never nail through the exposed face unless face nailing is specified.
- Drive nails flush, not overdriven; an overdriven nail breaks tile and a high nail head holds the tile off the course below.
- Confirm the required penetration into or through the sheathing, and use screws, foam closures, or adhesive where wind uplift demands them.
Worked example. A 2,000 sq ft roof is 20 squares. At 90 tiles per square the tile count is 1,800 pieces, and at two nails per tile the job needs 3,600 nails, plus 5 to 10 percent waste for cuts and breakage, so order about 2,000 tiles.
Traps. Overdriving fasteners; a single nail in a corner; starting at one rake and ending with a narrow cut at the other; ignoring interlocking side locks; fastening into the headlap of the wrong course so nails show.