Quick Summary
Many slate roofs on New Orleans historic homes fail at the fasteners rather than the stone. The nails rust through while the slate is still sound, and the National Park Service says plainly that plain steel and galvanized nails usually rust out long before the slate itself begins to deteriorate. That distinction matters, because a roof losing slates to failed fasteners can often be repaired rather than replaced. Big Easy Roofing works on slate across Orleans, Jefferson and St. Tammany parishes, where exterior work visible from the street in a historic district needs a Certificate of Appropriateness first, from either the Historic District Landmarks Commission or the Vieux Carre Commission.
Last Updated: September 2026
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A slate roof that is shedding pieces onto the garden looks like a roof at the end of its life. Usually it is not. The failure point on most historic slate is the fastener and the flashing, both of which have a far shorter service life than the stone, and telling those apart is the difference between a repair and a five figure replacement.
The fasteners commonly go first. National Park Service guidance states that non-ferrous slater’s nails, such as copper or stainless steel, should always be used, since plain steel and galvanized nails will usually rust out long before the slate itself begins to deteriorate. A roof nailed with plain steel will drop sound slates decades before the stone is spent.
Preservation Brief 29, written by Jeffrey S. Levine for the National Park Service, sets out four things that decide how long a slate roof survives: the physical and mineralogical properties of the slate, the way it was fabricated, the installation technique, and regular timely maintenance. Only the first is about the stone. The other three are workmanship, which is why two roofs of identical slate laid in the same decade age so differently.
Two installation faults show up repeatedly on older New Orleans roofs. Nail heads driven tight and left exposed accelerate deterioration by providing a point for water entry, because the slate should hang freely on the nail shank rather than be clamped against the deck. And where joints are improperly broken, meaning slates lap the joints in the course below by less than three inches, water passes between the joints,
By Big Easy Roofing 
Sep 9, 2026