Salt Air is the Enemy

Your hurricane straps, anchor bolts, and other connections are designed for specific loads. A strap rated for 1,500 pounds of uplift only works if the fasteners can handle that load. Corroded fasteners can lose 50-80% of their strength, meaning your 1,500-pound strap might only hold 300 pounds. That is not enough to survive a hurricane.

Both are stainless steel, but 316 contains molybdenum which dramatically improves resistance to salt water and chloride corrosion. In coastal Florida, 304 will eventually show pitting and corrosion in the most exposed areas. 316 costs about 20-30% more but provides significantly better long-term performance. For structural connections within 1500 feet of the coast, 316 is the right choice.

It depends on the location and application. Hot-dip galvanized (G185 or higher) works well for many applications outside the severe corrosion zone. But within 1500 feet of the coast, especially for critical structural connections like hurricane straps and anchor bolts, stainless steel is recommended. The small additional cost is worth it for 30+ year durability versus 15-20 year galvanized life.

You need to be careful about galvanic corrosion when different metals touch. Stainless steel and galvanized steel can accelerate corrosion at their contact point. Use isolation washers or keep materials consistent. If you are using stainless straps, use stainless fasteners. If you are using galvanized straps, use galvanized fasteners. Never use regular steel with stainless as this accelerates corrosion significantly.

Inspectors look for proper material markings and may use magnets to check for stainless steel (stainless is usually non-magnetic or weakly magnetic while regular steel is strongly magnetic). They also check that materials are appropriate for the coastal exposure zone. Keep documentation of your fastener specifications for the inspection. Some jurisdictions require submittals showing the fastener materials used.