Ridge Cap Installation

Ridge caps (and hip caps) are the pieces that cover the joint at the top of a roof and along its external hips. They bridge the gap between the two slopes and shed water down each side. Asphalt shingle roofs use purpose-made cap shingles or 3-tab shingles cut into pieces. Tile and slate roofs use ridge tiles, hip tiles or metal or lead rolls, often over a dry-fix or mortar bed.

Asphalt shingle method

Canadian guidance describes the following sequence:

1. Snap a chalk line along each hip or ridge so caps lie straight.
2. Start hips at the eaves and work upward. Start ridges at the end away from the prevailing wind so the laps face downwind.
3. Bend each cap so it projects equally on both sides.
4. Lap each cap over the previous one at the exposure the manufacturer specifies, usually equal to the field exposure.
5. Blind-nail about 50 mm (2 in) above the sealant strip so the next cap covers the nails.
6. Use longer nails than in the field: 32 mm (1 1/4 in) on new roofs and 38 mm (1 1/2 in) on re-roofs.

Where cap shingles are cut from 3-tab shingles, each shingle gives three caps. In cold weather the shingles can crack when bent, so they are warmed before use or bent after one side is nailed.

Ridge vents

Where a ridge vent is installed, the deck is cut back on each side of the ridge and the vent is fastened over the opening. The caps are then nailed through the vent with longer nails as the vent manufacturer specifies.

Tile and slate ridges

In the UK, BS 5534 requires ridge and hip tiles to be mechanically fixed whether or not mortar is used, and BS 8612 covers dry-fix ridge and hip systems. Mortar bedding remains traditional in many countries but is no longer relied on as the only fixing in the UK. Wood shingle ridges are made from pairs of overlapping boards or shingles, with joints alternated so that the ridge stays watertight as it ages.