Walls look simple on the surface, but inside,
wood-frame walls and LGS (light gauge steel) walls used in commercial interiors
are constructed in completely different ways.

This article explains:

1. Wood-frame wall basics (posts, studs, horizontal battens)
2. LGS wall basics (steel studs and runners)

This is a beginner-friendly guide designed for interior work and renovation projects.

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Part 1｜Wood-Frame Wall Basics (Houses / Timber Structures)

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■ 1｜Posts vs. “Interior Studs” (Mabashira)

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● Posts (Hashira)

Structural vertical members that support the building.

Typical sizes:

• 105 × 105 mm (standard)
• 120 × 120 mm (heavier load areas)

These are structural components and cannot be removed without engineering.

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● Non-structural studs (Mabashira)

Installed between posts to form the wall surface.
These do not carry structural loads.

Typical size:

• 30–45 mm × 90 mm

Functions:

• Support plasterboard
• Create a flat wall surface
• Provide spacing for insulation or wiring

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■ 2｜Horizontal Battens (Doubuchi)

Horizontal backing pieces inside the wall.

Functions:

• Fix plasterboard horizontally
• Adjust the straightness of the wall
• Improve installation accuracy

Typical size:

• 15–30 mm × 45 mm

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■ 3｜Wood-Frame Wall Structure (Text Diagram)

From the room side outward:

① Finish (paint, wallpaper, etc.)

↓

② Plasterboard (PB)

↓

③ Vertical studs + horizontal battens

↓

④ Structural post

↓

⑤ Exterior wall or adjacent room

This creates a grid-like wooden wall structure.

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Part 2｜LGS Wall Basics (Commercial / Offices / Stores)

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LGS (Light Gauge Steel) walls are non-structural interior partitions independent of the building frame.

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■ 1｜What Is LGS?

A wall system built using:

• Steel studs (vertical)
• Runners (horizontal channels)

Advantages:

• Perfectly straight
• Fire-resistant (required in commercial interiors)
• Suitable for tall partitions
• Fast installation

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■ 2｜Basic Components of an LGS Wall

● Stud (vertical)

Equivalent to a wooden interior stud.
Common spacing: 303 mm or 455 mm

● Runner (horizontal)

A channel fixed to the floor and ceiling into which studs are inserted.

● Plasterboard

Same as wood construction (9.5 mm or 12.5 mm typical).

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｜LGS Stud Sizes (65mm / 75mm / 100mm) and Proper Use

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Understanding stud sizes is critical in commercial interiors.

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■ 1｜65mm Stud (S-65)

The most common size used in standard interior partitions.

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● Typical Uses

• General interior partitions
• Back-of-house walls
• Residential renovation internal walls
• Light-load partitions

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● Advantages

• Lower material cost
• Lightweight
• Slim wall thickness

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● ⚠ Important Note: Height Limit (~4.0 m)

Manufacturers generally specify approx. 4.0 m as the upper limit for 65mm studs.

However, this is only valid under standard conditions, such as:

• JIS-compliant studs
• Correct stud spacing (303–455 mm)
• No heavy loads (shelves, wall-mounted units, TVs, etc.)
• No large openings
• Adequate bracing or anti-sway reinforcement
• Standard single- or double-layer PB

If any of these conditions are not met, 75mm or 100mm studs should be used instead.

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■ 2｜75mm Stud (S-75)

Slightly stronger and more stable than 65mm.

● Typical Uses

• Partitions around 3.0–3.5 m high
• Areas where moderate rigidity is needed
• Spaces requiring minor sound control
• Walls subject to vibration or foot traffic

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■ 3｜100mm Stud (S-100)

A high-strength option used in more demanding wall applications.

● Typical Uses

• Tall partitions (3.5–5.0 m)
• Soundproof walls (multi-layer PB, insulation)
• Equipment rooms / mechanical spaces
• Walls needing large internal cavities (ducts, pipes, cabling)
• Walls requiring very high rigidity

● Advantages

• Very strong against bending
• Accommodates more services inside the wall
• Easier to achieve high sound insulation ratings

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■ Stud Size Selection Summary

A simple way to remember:

65mm → Standard partitions（Up to ~4 m under correct conditions）

75mm → Taller walls or when extra rigidity is needed

100mm → High walls, soundproofing, or equipment-heavy walls

This rule-of-thumb dramatically improves design speed and accuracy in commercial interiors.

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Summary

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Wood-frame walls

• Posts + interior studs + battens
• Structural and non-structural walls mixed
• PB used as the finish base

LGS walls

• Studs + runners + PB
• Non-structural but highly flexible
• Stud size selection directly affects wall strength and performance
• 65mm is valid up to approx. 4.0 m IF conditions are met

Understanding these fundamentals allows you to design and supervise interior walls with confidence.

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■ Disclaimer (English Edition)

This article explains general principles of wood-frame and LGS interior wall construction.
Actual requirements vary depending on wall height, load conditions, equipment layout, and building regulations.
Always consult qualified professionals when designing or modifying interior partitions.