| Carbon steel | Welded vertical bars, horizontal rails, ornamental patterns | Stairs, balconies, platforms, industrial walkways | Low without protective coating; improved by galvanizing and/or a suitable paint system | Inspect coatings and joints; repair damaged areas to limit rust | Confirm steel grade, coating specification, weld quality, and required exposure category |
| Hot-dip galvanized steel | Post-and-rail, welded mesh infill, modular guardrails | Outdoor stairs, bridges, public facilities, warehouse platforms | Zinc coating provides a protective barrier and sacrificial protection; service life varies with environment and coating thickness | Usually low; check for coating damage, drainage issues, and corrosion at cut edges | Specify the applicable galvanizing standard and whether additional paint or powder coating is required |
| Stainless steel 304 | Round or square posts, tube-and-rail systems, cable infill | Interior stairs, commercial buildings, sheltered outdoor areas | Good general corrosion resistance in many inland and indoor settings; less suitable than 316 for chloride-rich exposure | Clean periodically; avoid contaminating the surface with carbon-steel tools or residues | Check the stated alloy grade and surface finish; appearance alone cannot verify stainless grade |
| Stainless steel 316 | Marine-grade posts, glass-clamp systems, cable or rod infill | Coastal buildings, marinas, pool areas, exposed outdoor locations | Generally better resistance to chloride pitting than 304; not immune to corrosion | Rinse salt deposits and clean regularly, especially in coastal or pool environments | Confirm the alloy of the complete system, including fasteners and fittings |
| Aluminum | Extruded picket rails, framed panels, modular balcony systems | Residential balconies, terraces, ramps, light-duty outdoor settings | Good atmospheric corrosion resistance; coating choice and dissimilar-metal contact matter | Generally low; clean surfaces and inspect coatings and connections | Compare alloy, temper, section design, finish, and engineering for the required loads |
| Wrought iron / wrought-iron-style steel | Decorative scrolls, forged balusters, custom ornamental panels | Heritage properties, entrance steps, gardens, decorative balconies | Requires a protective coating; performance depends on preparation, coating, and exposure | Inspect decorative joints and coating; touch up chips before corrosion spreads | Clarify whether the product is traditional wrought iron or modern steel made in a wrought-iron style |
| Metal frame with glass infill | Post-supported glass panels or base-shoe systems | Balconies, terraces, staircases, view-facing decks | Depends on frame and hardware material; glass itself does not rust | Clean glass and inspect seals, clamps, fixings, and drainage details | Verify safety-glass type, panel thickness, edge treatment, and system-specific structural testing |