For framers and contractors working in Florida, South Carolina, coastal Georgia, or anywhere along the Gulf Coast, the climate is not a background condition — it’s an engineering variable. High humidity, salty air, driving rain, and hurricane-force winds create a set of demands that standard interior framing details don’t fully address. Cold-formed steel handles these environments well, but only when it’s specified and installed correctly. Rising global surface temperatures increase the likelihood of severe climate events even further from the coastal territories, and contractors everywhere could benefit from knowing how to build with CFS.
This article covers the coating specifications, detailing practices, and design considerations that matter most in high-humidity and coastal framing applications.
The comparison most framers make is against wood, and it’s not a close contest in coastal environments. Wood absorbs moisture, swells, shrinks, and eventually rots. It supports mold growth when moisture content remains elevated. In hurricane-prone areas, repeated exposure to wind-driven rain accelerates deterioration in framing members that never fully dry out.
Cold-formed steel doesn’t absorb moisture, doesn’t rot, and won’t support mold growth. It also doesn’t shrink or swell with seasonal humidity changes, which means the framing stays dimensionally stable and finishes stay intact over time. Steel is also non-combustible, which matters in coastal markets where insurance premiums for wood-framed buildings have increased substantially in recent years.
The main vulnerability of steel in corrosive environments is the zinc coating. Understand that coating, respect it in your detailing, and cold-formed steel is an excellent choice in coastal and high-humidity construction.
Cold-formed steel framing is galvanized — coated with zinc — to resist corrosion. The coating weight is measured in ounces of zinc per square foot of total steel surface (both sides), and the two most common designations are:
G60 — 0.60 oz/ft² total coating weight. This is the standard specification for most interior, protected framing applications. Typical interior partition walls in climate-controlled spaces are G60 territory.
G90 — 0.90 oz/ft² total coating weight. This is required for exterior applications, exposed conditions, and high-humidity environments where moisture exposure is elevated or ongoing.
In coastal and high-humidity markets, G90 is typically required for:
G60 and G90 studs look identical. Confirm the coating designation from the product label or mill cert before installation — a visual inspection won’t tell you which you have.
Some coastal projects spec G135 (0.90 oz/ft² hot-dip galvanized) or stainless steel fasteners for particularly aggressive salt-air exposure. If you’re working within a few blocks of the ocean in a high-humidity market, review the spec carefully and ask the GC whether the structural engineer has issued specific corrosion protection requirements.
In a humid climate, moisture management at the building envelope is where most long-term problems start. The framing contractor isn’t responsible for the waterproofing membrane, but the framing details you install either support or undermine what comes after.
Keep framing off direct concrete contact where possible. When CFS floor track is installed directly on a concrete slab, particularly in a slab-on-grade or below-grade condition, moisture can wick from the concrete into the track. In most cases, a continuous sill gasket or isolation tape between the track and slab is the right detail. This is also required by many building codes as a capillary break.
Use proper clips and blocking at window and door openings. In coastal construction, window and door openings are where wind-driven water gets in. Sill clips, head flashing, and properly lapped membrane at rough openings are typically the window installer’s or waterproofing subcontractor’s scope, but confirm that the framing scope includes the backup framing required to support those details.
At exterior sheathed walls, maintain the drainage plane. The framing provides the substrate; the WRB (weather-resistive barrier), sheathing, and drainage plane details allow moisture that gets past the cladding to drain out rather than become trapped in the wall cavity. Your stud spacing and sheathing attachment requirements come from the engineering — but understanding the whole-wall system helps you identify conflicts before they become field problems.
Florida, coastal Georgia, and coastal South Carolina are within the high-wind regions defined by ASCE 7. Design wind speeds in coastal Florida can exceed 170 mph. These wind loads drive the structural requirements for exterior framing, and the engineering is more rigorous than you’ll see in inland commercial construction.
Key differences you’ll encounter in high-wind framing:
Heavier gauge exterior studs. Where an interior partition might be framed with 18-mil or 33-mil material, exterior curtain wall framing in high-wind zones is often specified at 43-mil, 54-mil, or heavier. The stud acts as a flexural member spanning between floor and ceiling under lateral wind pressure, and limiting heights tables don’t extend to high-wind conditions without engineering.
Closer stud spacing. 16″ o.c. is common where 24″ o.c. might be used inland. On some exterior walls in high-exposure zones, 12″ o.c. is specified.
Engineered connections at the top and bottom. Wind uplift and lateral load require anchors and fasteners that go beyond standard partition track screws. Look for hold-down straps, anchor bolts, or engineered clip connections at the base of exterior walls.
Bridging and blocking requirements. Stud bridging in structural exterior walls is typically specified at much closer intervals than in standard partitions, to prevent lateral-torsional buckling under wind load.
If you’re bidding exterior framing in a coastal high-wind zone without a set of engineering drawings, get them. The design requirements in these markets are meaningfully different from standard commercial framing, and the difference shows up in both material cost and labor.
In humid climates, the framing assembly needs to dry in both directions — toward the interior and toward the exterior. Trapping moisture in the wall cavity creates the conditions for corrosion at fastener penetrations and at any locations where the zinc coating was compromised during installation.
A few practical considerations:
Don’t let framing sit unprotected for extended periods. Once sheathing is installed on an exterior wall, get the WRB and flashing on it. Framing left open to weather during the rainy season accumulates moisture it may never fully release.
Protect material on the jobsite. G90 steel is corrosion-resistant, not corrosion-proof. Material stored in standing water or under wet tarps for weeks is accumulating exposure before it’s even installed. Store material off the ground on blocking, keep it covered, and move it inside or under cover if the job is going to be down for an extended period.
Seal penetrations through the framing. In a humid climate, every hole through an exterior stud or track is a potential moisture entry point. Electrical, plumbing, and mechanical penetrations through exterior framing should be properly sealed per the spec.
Cold-formed steel is a strong choice for coastal and high-humidity construction when the right material specs and details are followed. The steel itself is durable; the details are what make the difference between a building that performs for decades and one that generates service calls.
The Formetal Company supplies cold-formed steel studs and track to framers throughout the Southeast, including the Florida, South Carolina, and coastal Georgia markets. We stock G90-coated product and can provide mill certifications for projects that require documentation. Contact us to discuss your project’s requirements, use our Price Calculator to generate a quote today, or our Submittal Builder to check out our specifications.