G90 vs G60 Corrosion Protection for Type B Metal Decking in Florida
We offer G90 vs G60 Type B metal deck corrosion protection assessments, specification review, material supply, and warranty-backed QA across Florida.
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Summary
- G90 has heavier zinc coating than G60
- Choose G90 for coastal exposure
- We supply spec, QA, and warranty-backed materials
Understanding G90 vs G60 corrosion protection is critical when specifying Type B metal decking in Florida where humidity and salt accelerate corrosion. G90 and G60 are ASTM A653 zinc coating designations: G60 is about 0.60 oz/ft2 (183 g/m2) and G90 is about 0.90 oz/ft2 (275 g/m2). Miami Metal Deck evaluates exposure, durability needs, and lifecycle cost so your project gets the right coating and documented compliance.
How G60 and G90 Differ
The main difference is coating mass and corrosion resistance: G90 offers roughly 50 percent more zinc than G60 which translates to significantly longer sacrificial protection in aggressive environments. In coastal or high humidity situations that extra zinc delays perforation, reduces maintenance, and extends service life. G60 can be cost effective for inland, low-salt exposure projects where the risk of accelerated corrosion is lower.
For Type B metal decking used in Florida construction consider the local exposure class, finish handling, and end use. Type B deck profiles used for elevated floors or composite slabs lose protection at cut edges and penetrations, so choose G90 for areas with frequent wetting or salt spray and G60 where exposure is limited and budgets are constrained.
Standards, Field Handling, and Specification Tips
Specify ASTM A653 coating class explicitly in contract documents and require mill test reports to confirm coating mass. Account for field cutting, punch holes, and welds which remove coating; require zinc-rich touch-up paint or mechanical edge treatment. Clarify warranty terms, expected maintenance intervals, and acceptance criteria for visible corrosion at handover.
Compare upfront material cost to lifecycle cost: G90 costs more per ton but lowers repair, replacement, and downtime risk in coastal Florida. For long-term value, model service life, maintenance cycles, and residual value rather than selecting solely on initial price.
Why Choose Miami Metal Deck
Miami Metal Deck brings local Florida expertise, specification review, certified installation teams, and documented QA processes. We review exposure conditions, recommend appropriate coating class, verify mill certifications, and provide warranty-backed supply options to reduce owner risk and ensure code compliance.
For many Florida projects the practical recommendation is to specify G90 for coastal and corrosive environments and G60 for protected, interior, or low-corrosion sites. Document the decision in the submittal, require MTRs, and include field touch-up procedures to protect cut edges.
Selecting the Right Option for Your Project
Decision guideline: if project faces salt spray or high humidity select G90; if interior or low-salt exposure select G60 with protective detailing. Always require ASTM A653 designation, mill test reports, and specified touch-up procedures to maintain warranty and long-term performance.