0.75mm vs 1.0mm Steel Studs: Which to Specify?

In short: Choose 0.75mm cold-formed steel studs for properly engineered, low-rise residential walls with moderate loads. Specify 1.0mm studs where greater axial capacity, stiffness or connection strength is required, particularly for two-story villas and higher wind exposure. At identical section geometry, 1.0mm steel provides approximately 33% more gross steel area, but actual load capacity depends on buckling and restraint.

What Is the Real Thickness of 0.75mm and 1.0mm Steel Studs?

Steel stud thickness refers to the base steel thickness, not the complete thickness including the zinc coating. This distinction matters when comparing supplier quotations and structural specifications.

Cold-formed steel studs are commonly manufactured from galvanized structural steel coils. A nominal 0.75mm stud has a base metal thickness of 0.75mm, while a 1.0mm stud has a base metal thickness of 1.0mm. The difference is 0.25mm, representing a 33.3% increase in base steel thickness.

Some suppliers quote coated thickness rather than base metal thickness. Buyers should request the actual base metal thickness and coating specification. For consistent purchasing, the specified thickness should be verified against the applicable material standard and mill inspection certificate.

Two commonly used structural steel grades are S280GD and S350GD under EN 10346. Their minimum yield strengths are 280MPa and 350MPa respectively. S350GD offers approximately 25% higher minimum yield strength than S280GD, but this does not automatically mean 25% higher stud capacity.

• S280GD: Minimum yield strength of 280MPa. Suitable for engineered residential framing where the calculated section capacity meets the design loads.
• S350GD: Minimum yield strength of 350MPa. Provides higher material strength for demanding structural applications.
• Coating: Specify the required zinc coating mass, such as Z275, according to exposure conditions and project requirements.

How Much More Load Can a 1.0mm Steel Stud Carry?

Thickness directly affects the steel area available to resist compression. Consider a typical illustrative C-section with a 90mm web, 40mm flanges and 10mm lips. Its developed flat width is approximately 190mm, excluding bend allowances.

At 0.75mm thickness, the approximate gross steel area is 142.5mm2. At 1.0mm, it increases to 190mm2. This represents a 33.3% increase in gross cross-sectional area when the section geometry remains unchanged.

However, a stud installed at 3m height does not behave like a short compression block. Its actual axial load capacity depends on member buckling, local buckling, distortional buckling, effective section properties and end restraint.

For example, two studs with identical dimensions but different thicknesses may have substantially different capacities. The thicker section generally performs better, but its capacity cannot be established from thickness alone.

Designers should calculate compression capacity using AS/NZS 4600 where this standard governs the project, or the applicable cold-formed steel design standard in the destination market. Calculations must include the actual section dimensions, steel grade, 3m effective length, restraint conditions and load eccentricity.

The following comparison uses a 190mm developed width and a steel density of 7,850kg/m3. The mass figures are theoretical stud-only estimates. Axial capacity must be established by engineering calculations rather than assumed from thickness.

0.75mm vs 1.0mm Steel Studs: Technical Comparison

The mass calculation assumes 2.5 studs per meter of wall length at 400mm spacing and approximately 1.67 studs per meter at 600mm spacing. It excludes tracks, bracing, noggings, fasteners and openings.

Should You Choose 400mm or 600mm Stud Spacing?

Stud spacing determines how many vertical members support the wall. It also affects the load transferred to each stud, wall stiffness and the performance of sheathing and cladding.

At 400mm centers, the wall contains approximately 2.5 studs per meter. At 600mm centers, it contains approximately 1.67 studs per meter. Moving from 400mm to 600mm spacing reduces the number of studs by approximately 33%.

This can reduce framing material and labor costs. However, each stud must support a larger share of the wall and roof loads. Wider spacing may also require stronger sheathing, additional blocking or revised connection details.

• 400mm spacing: A practical starting point for residential walls with higher stiffness requirements, heavier cladding or demanding wind loads.
• 600mm spacing: A potential cost-saving option for engineered wall systems with suitable sheathing and verified load capacity.
• Roof and floor framing: Spacing must be selected separately according to span, dead loads, live loads and support conditions.

Do not select 600mm spacing simply because the studs are 1.0mm thick. Both thickness and spacing must be checked as part of the complete wall assembly.

How Do Stud Thickness and Spacing Affect Cost, Freight and Foundations?

Steel thickness affects material cost because thicker studs contain more steel. For identical section geometry, increasing thickness from 0.75mm to 1.0mm increases stud material mass by approximately 33.3%.

At 400mm spacing, the estimated stud-only mass increases from 2.80kg/m2 to 3.73kg/m2. For a 200m2 wall area, this represents an increase of approximately 186kg. Actual shipment weight will be higher after adding tracks, connections, bracing and other framing components.

Additional steel weight affects container loading, freight calculations and handling. However, freight is not determined by weight alone. Packaging dimensions, container utilization, shipping volume and destination charges also matter.

Foundation design requires similar attention. Increasing stud thickness adds some permanent structural weight, but the foundation is usually influenced more by building geometry, soil bearing capacity, roof loads, floor loads, wind uplift and seismic forces.

A 33.3% increase in stud material does not mean a 33.3% increase in foundation size. The structural engineer must evaluate the complete load path from roof and floors through the walls to the foundation. Thicker studs may also reduce the need for certain reinforcement measures, depending on the design.

Which Steel Stud Thickness Should You Specify for Different Building Heights and Wind Zones?

The correct specification depends on building height, structural layout and local environmental conditions. The following rules are preliminary selection guidance, not substitutes for project-specific calculations.

• Single-story villas: 0.75mm studs may be suitable for non-critical and load-bearing walls where section capacity, wall height and connections are verified. A 400mm or 600mm spacing arrangement can be considered according to the engineering design.
• Two-story villas: Consider 1.0mm studs for heavily loaded ground-floor walls, concentrated loads and areas supporting upper-floor framing. Lighter sections may still be suitable in selected locations.
• Three-story buildings: Use a complete engineered framing schedule. Do not assume that either 0.75mm or 1.0mm is sufficient without checking compression, stability and connection capacities.
• Moderate wind zones: Stud thickness and spacing should satisfy the calculated wind pressure, internal pressure and wall deflection limits.
• High wind zones: Prioritize verified structural capacity, stronger connections, hold-down systems and adequate sheathing. A thicker stud alone cannot guarantee wind resistance.

For wind design, engineers should use the applicable local standard. In Australia, AS/NZS 1170.2 addresses wind actions. In other markets, the relevant national building code and wind-loading standard must govern.

For residential light steel villas, a mixed-thickness specification is often more economical than using 1.0mm studs throughout. For example, a project may use 1.0mm sections at heavily loaded ground-floor walls and 0.75mm sections at appropriately designed upper walls and partitions. Every member must still satisfy the applicable design requirements.

Quick answers

Is 1.0mm steel stronger than 0.75mm? Yes. It provides approximately 33.3% more gross steel area with identical section geometry, although actual structural capacity depends on buckling and restraint.

Can 0.75mm studs support a 3m-high wall? They can be suitable in some designs, but the 3m member height, section dimensions, loading and restraint must be checked by an engineer.

Is 400mm spacing better than 600mm? It provides more frequent structural support and generally improves wall stiffness, while 600mm spacing can reduce material use when the complete wall system is engineered for it.

Next step: Review our light steel villa framing and structural solutions, explore our light steel villa engineering information, or contact our engineering team with your building height, floor plan, wind zone and preferred stud spacing for a project-specific framing proposal.