What kind of flashing material holds up on a chimney in coastal New Brunswick where aluminum corrodes from the salt?

Stainless steel flashing is your best bet for coastal New Brunswick chimneys — specifically 316 marine-grade stainless steel, which contains molybdenum for superior corrosion resistance against salt air. You're absolutely right that standard aluminum flashing fails quickly in coastal environments like Saint John, Shediac, or anywhere along the Bay of Fundy.

Marine-grade stainless steel (316) costs significantly more than aluminum — expect $8-12 per linear foot versus $3-5 for aluminum — but it's a one-time investment that can last 30+ years in salt air. The 316 grade specifically resists pitting and crevice corrosion that destroys lesser metals. Many roofers in coastal areas have switched to this exclusively after seeing too many callbacks from failed aluminum installations.

Lead-coated copper is another excellent coastal option, particularly popular with heritage restoration contractors working on older Saint John and St. Andrews properties. Lead coating prevents the green patina that can stain masonry, and copper naturally resists corrosion. Cost runs $10-15 per linear foot, but it's extremely durable and can be soldered for watertight joints.

For step flashing specifically, many coastal contractors prefer pre-formed stainless steel pieces over field-bent aluminum. The factory edges hold up better to wind-driven salt spray, and you avoid the stress points that develop when bending softer metals on-site. When installing any coastal flashing, use stainless steel fasteners — never mix metals or you'll create galvanic corrosion.

Installation timing matters significantly in coastal New Brunswick. Salt air accelerates corrosion of any exposed cut edges, so all flashing work should be completed quickly and sealed immediately. Spring installation (May-June) gives the best weather window before summer storms and winter freeze-thaw cycles.

Your best next step is getting quotes from roofers experienced with coastal installations — ask specifically about their material choices for salt air environments and request references from other coastal properties. A quality marine-grade installation will cost 2-3 times more upfront but eliminates the cycle of repeated repairs that plague cheaper materials in your environment.