The ridge of a roof is the highest point of the water management system — the last line before the two slopes separate. A ridge cap that fails allows water into the structure at the peak. On a slate or cedar shingle roof, the ridge cap should be in a material that matches the durability of the primary roofing surface. Copper is that material.
A copper ridge cap runs the full length of the ridge, formed into an inverted V profile that covers the junction of the two roof slopes. On a slate roof, it is set over the top course of slates on each side. On a cedar shingle roof, it covers the top courses of shingles. The copper reads as a bright line at the ridge when new, darkening with patina over years to blend with the roof surface.
Ridge cap copper for a residential roof is 16-ounce cold-rolled copper, formed to the specific pitch of the roof and the ridge angle. It is installed in sections of 8 to 10 feet, lapped a minimum of 4 inches at each joint, secured with copper cleats that allow thermal movement. A continuous ridge cap is not field-formed in single pieces — it is fabricated in manageable lengths.
Copper ridge caps perform for 50 to 75 years or more, consistent with the life of the copper gutter and flashing system. The primary maintenance item is the lap joints — inspect them every 10 years and resolder any that have opened. The copper itself does not fail.
Copper ridge caps are correct on slate and cedar shingle roofs because they last as long as the roof below them. An asphalt or painted metal ridge cap on a slate roof requires replacement every 20 to 30 years. A copper ridge cap does not.
Through the sheet metal contractor installing or maintaining the roof. Specify 16-ounce copper, lap joints soldered, copper cleats for attachment. This is a standard item for any sheet metal contractor who works in copper.
Sixteen-ounce copper ridge cap, lapped 4-inch minimum at joints, joints soldered, copper cleat attachment for thermal movement, at the ridge of all slate and cedar shingle roofs on traditional New England buildings. This is the correct material at the highest and most vulnerable point of the roof.
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