Light Steel Construction for Interior Walls, Exterior Walls, and Floors

Light Steel Construction for Interior Walls, Exterior Walls, and Floors: Light gauge steel framing (LGSF) has rapidly become a popular construction method for both residential and commercial buildings. The cold-formed steel profiles used in this system form the building’s load-bearing skeleton.

• Fast assembly and low cost
• Flexible design and high strength
• Eco-friendly (recyclable material)

Thanks to these advantages, it is preferred in many projects over traditional reinforced concrete or wooden constructions.

In light steel buildings, exterior walls, interior walls, and floor systems (upper floor load-bearing elements) are generally constructed using specific types and thicknesses of profiles. The key is to select the appropriate dimensions and cross-sections based on the building’s intended use, its geographical location (earthquake loads, wind loads, etc.), and the project’s design requirements.

1. Key Features of Light Steel Profiles

1.1. Production Method: Cold-Forming

Light steel profiles are produced by cold-forming thin steel sheets fed from rolls through rollforming machines. There are several important reasons why cold-forming is preferred over hot rolling. First, cold-forming makes it possible to achieve a higher strength-to-thickness ratio. Because the steel is bent without an increase in temperature, the crystalline grains within the material become compressed, resulting in greater strength. At the same time, the production process is more controlled, and profiles can be manufactured quickly and accurately in the desired dimensions, thicknesses, and cross-sections.

Additionally, surface protection is crucial for light steel profiles. This protection often involves galvanized coatings (for example, G90 standard) or Aluzinc coatings. In galvanizing, the steel surface is coated with zinc to increase its resistance to corrosion (rust). Aluzinc coating, on the other hand, creates an aluminum-zinc alloy layer that provides long-lasting protection, especially for buildings exposed to high humidity or harsh outdoor conditions. Thus, light steel profiles stand out for their thin cross-sections and high strength, while also offering excellent corrosion resistance that significantly reduces maintenance costs. These attributes are the main reasons why light steel buildings are preferred as a long-lasting and reliable solution under various climatic conditions.

1.2. Profile Types

The most commonly used profile cross-sections are:

1. C Profile (Stud):
   • Frequently used as a vertical load-bearing element.
   • Placed vertically within the wall system.
   • Flange width, profile height, and thickness are determined according to the project requirements.
   • Example: 90 mm × 41 mm × 0.8 mm C profile (for interior walls) or 150 mm × 41 mm × 1.2 mm C profile (for exterior walls), or 150 mm × 41 mm × 1.6 mm C profile (for exterior walls).
2. U Profile (Track or Base-Top Profile):
   • Used horizontally at the base and top of walls.
   • Guides and fixes the C profiles in place.
   • Example: 90 mm × 41 mm × 0.8 mm U profile, 150 mm × 50 mm × 1.2 mm U profile, or 150 mm × 41 mm × 1.6 mm U profile.
3. Sigma or Z Profile:
   • Can be used for roof trusses, beams, or purlins.
   • Preferred for large spans or special engineering solutions.
   • Produced in sheet thicknesses of 3–4 mm.
4. L Profile (Corner Profile):
   • Used at wall corners, around door and window openings, and at connection points.

1.3. Material Thicknesses

Light steel profiles generally range in thickness from 0.8 mm to 2.5 mm. When choosing the thickness, consider:

• Load-bearing capacity (load distribution, number of floors)
• Earthquake regulations and wind loads
• Thermal and acoustic insulation requirements
• Fire resistance criteria

In interior walls, thicknesses of 0.8–1.2 mm are often sufficient, whereas 1.2–2.0 mm thicknesses may be required for exterior walls and floor-bearing profiles.

2. Exterior Walls: Profiles Used and Base Dimensions

In light steel systems, exterior walls form both the building’s load-bearing shell and protect it from external factors (weather, water, heat, sound). Therefore, the profiles used for exterior walls are typically larger and thicker compared to those used for interior walls.

2.1. Selecting Exterior Wall Profiles

• C Profile Web Width:
  Common widths include 120 mm, 140 mm, or 150 mm. A wider profile allows for a thicker insulation layer (e.g., glass wool, rock wool).
• Flange and Lip Lengths:
  The flanges (the side edges of the profile) and lip parts are crucial for stability. Because wind loads on exterior walls can be significant, the flange width must be adequate. Generally, a 1.00 mm lip is used.
• Sheet Thickness:
  Thicknesses such as 1.2 mm, 1.6 mm, or 2.0 mm are common in exterior walls. The final choice depends on the project’s structural calculations.

2.2. Base Profiles (U Profiles)

Exterior wall base profiles are fastened to the floor slab or foundation and facilitate the placement of vertical C profiles. Typically, the U profile width matches that of the C profile used in the exterior walls (for example, 150 mm wide).

• Example:
  • U150×50×1.2 mm: 150 mm in width, 50 mm flange, 1.2 mm sheet thickness.

2.3. Exterior Wall Insulation and Cladding

The exterior side of light steel walls is generally clad with OSB or similar structural sheathing. On top of this sheathing, additional layers of waterproofing, thermal insulation, and a final exterior finish (such as siding, composite panels, or an exterior paint system) are applied.

• Rock wool or glass wool insulation provides thermal and acoustic protection.
• Fibercement, PVC siding, or aluminum composite materials are often chosen for external finishes.

3. Interior Walls: Light Steel Profiles and Sound Insulation

Interior walls are divided into two main categories based on whether they bear loads:

• Load-Bearing Interior Walls: Form part of the structural frame and transfer loads.
• Partition Walls (Non-Load-Bearing): Partition spaces within the structure and use thinner, lighter profiles.

3.1. Profile Selection

• Partition walls: Typically use C profiles with widths of 60 mm or 90 mm and thicknesses from 0.8 mm to 1.2 mm.
• Load-bearing interior walls: Often use widths of 100 mm or 120 mm and thicknesses of 1.2 mm to 1.6 mm.

3.2. Base Profiles

Interior walls also use U profiles (track) with the same width as the C profiles. For example, if using a 90 mm C profile, select a 90 mm U profile.

3.3. Sound Insulation

A critical aspect of light steel interior wall systems is acoustic insulation. Significant sound reduction can be achieved by installing mineral wool or glass wool within the wall cavity. Moreover, using double layers of gypsum board (e.g., two 12.5 mm sheets) can further increase sound insulation.

3.4. Fire Resistance

To meet fire code requirements, fire-rated gypsum boards (e.g., A1 class) or non-combustible insulation materials around steel profiles may be used in interior walls. Increasing the profile thickness and applying double-layer drywall can extend fire resistance times.

4. Upper Floor(s) and Flooring Systems

One of the greatest advantages of light steel construction is the ability to quickly and easily assemble upper floor systems. In traditional concrete slabs, you need to set up formwork, prepare rebar, and pour concrete. In contrast, these steps can be largely eliminated or shortened in light steel systems thanks to pre-fabricated elements. This leads to savings in both labor and time. Since upper floors are typically formed with light steel joists and OSB or steel decking in between, the flooring system of each floor is extremely light yet highly durable.

Additionally, it is straightforward to integrate insulation materials (e.g., mineral wool, rock wool, XPS) into these floor layers, offering effective sound and thermal control. This not only increases occupant comfort but also reduces energy costs. By using appropriate fasteners (screws, rivets, bolts) during production and installation, and designing each floor according to proper engineering calculations, light steel floors remain both long-lasting and low-maintenance. Altogether, assembling upper floors in a light steel building offers a more flexible, cost-effective, and time-saving solution compared to conventional reinforced concrete methods.

4.1. Load-Bearing Joist Profiles

In upper floor construction, the main load-bearing elements generally consist of C or Sigma (Σ) joist profiles.

• Span: Spans of 3–6 meters can be crossed easily; larger spans require thicker or specially designed profiles.
• Profile Dimensions: Cross-sections such as 200 mm × 50 mm × 1.6 mm or 250 mm × 50 mm × 2.5 mm may be chosen.
• Spacing (on center): Commonly 40 cm, 60 cm, or 62.5 cm, which aligns with the dimensions of the chosen sheathing materials (OSB, cement-bonded particleboard, etc.).

4.2. Floor Sheathing

• OSB (Oriented Strand Board) or cement-bonded particleboard is frequently used for upper floor decking.
• Typical thickness choices include 18 mm or 22 mm OSB.
• Additional layers can be added for reinforcement if needed.

4.3. Sound and Thermal Insulation

Sound and thermal insulation, such as mineral wool or extruded polystyrene (XPS), can be placed between the layers of the floor system, significantly reducing heat transfer and noise between floors.

4.4. Final Surface (Screed and Floor Finish)

A lightweight screed (self-leveling screed, etc.) is applied on the upper floors to level the surface, after which the final flooring material (e.g., parquet, ceramic tiles, vinyl, or carpet) can be installed. This approach provides a similar level of comfort and solidity to that of traditional concrete slabs.

5. Technical Data and Calculations

Engineering calculations for light steel projects are based on steel structure regulations and any relevant local seismic codes. International standards like the AISI (American Iron and Steel Institute), EUROCODE 3, or BS 5950 can also provide guidance. In Turkey, the Earthquake Code and Steel Structures Code must be followed.

• Axial Load Capacity: Profile and thickness selections take into account the number of floors and roof load.
• Wind and Lateral Loads: Particularly for exterior walls, wind and earthquake loads are calculated according to the project’s requirements.
• Section Strength (Bending, Shear, Buckling): Flange width, lip length, and sheet thickness all affect these parameters.
• Connections: Screwed, riveted, or bolted connections are used. The type and number of these connection points are critical for load-bearing capacity.

6. Assembly Process and Key Considerations

1. Pre-Fabrication and Numbering System
   Light steel panels or profiles can be precisely cut and formed in a factory using CAD/CAM technology. Each piece is numbered, speeding up on-site installation.
2. Substrate Preparation
   Base profiles must be fastened on a level surface (e.g., a concrete raft foundation or slab). Proper alignment and leveling prevent issues in subsequent stages.
3. Installing Vertical Profiles
   Vertical C profiles are inserted into the U profiles and secured according to the connection details. For exterior walls, wind bracing (e.g., diagonal bracing, panel sheathing) is installed as required.
4. Interior Wall and Floor Installation
   Interior walls are added after the main load-bearing framework is assembled, functioning as partition walls. Upper floor joists and decking are installed in coordination with the height of the C profiles.
5. Insulation and Cladding
   The insulation materials are placed within the walls, followed by interior and exterior cladding materials (OSB, gypsum board, fibercement, etc.).
6. Inspection and Supervision
   As the building progresses, the positions of load-bearing elements and the quality of connections must be carefully checked. Structural supervision ensures compliance with regulations.

7. Sample Profile Selection Table (Illustrative)

Below is an illustrative table of commonly used profile sizes for exterior walls, interior walls, and floor joists. (In actual projects, selections are based on specific engineering calculations.)

8. Summary of Advantages

1. Fast Assembly: Prefabricated or on-site assembly options speed up the project timeline.
2. Lightweight: Reduced foundation loads, lower transportation, and crane costs.
3. High Strength: Thin-profile sections can form a strong load-bearing system.
4. Flexible Design: Architects can easily achieve desired layouts and forms.
5. Insulation Capability: Exterior walls offer ample depth and cavity space for high-level thermal and acoustic insulation.
6. Eco-Friendly: Steel is recyclable; less waste is produced, and the building’s lifespan is extended.

Recommendations

Light steel construction technology offers fast, durable, and cost-effective solutions for exterior walls, interior walls, and upper floors in both residential and commercial projects. Correct profile selection, appropriate base dimensions, and proper insulation/cladding details ensure a long-lasting and high-performance system.

• During the Project Phase:
  • Architects and engineers should design in accordance with relevant regulations.
  • Loads, earthquakes, wind, and other factors must be thoroughly calculated.
• During Production and Assembly:
  • Profiles cut and numbered in the factory should be assembled correctly on-site.
  • The quality and quantity of fasteners must adhere to project specifications.
• Quality Control and Supervision:
  • Inspections at both manufacturing and assembly stages safeguard material quality and structural integrity.
  • Authorized engineers’ signatures and approvals document each step.

Today’s architectural and construction trends are leaning toward sustainable, fast, and efficient solutions. Light steel systems meet these needs by offering a wide range of profiles in various sizes—from exterior walls and interior partitions to floors and roof trusses—providing an ideal alternative. If you are planning a new project or looking to improve an existing one, you should certainly consider the advantages offered by light steel construction.

References and Further Reading

• American Iron and Steel Institute (AISI) – North American Specification for the Design of Cold-Formed Steel Structural Members.
• European Convention for Constructional Steelwork (ECCS) – Technical guides and design examples.
• TS 498, Earthquake Code, and Steel Structures Code – Standards and regulations in effect in Turkey.
• Technical Associations and Platforms – Steel Framing Alliance, World Steel Association, etc.

NOTE: This blog post provides a brief overview of how exterior walls, interior walls, and floor systems are designed with light steel profiles and which profiles are typically chosen. For more detailed requirements specific to your project, you should seek engineering and architectural design guidance. Remember, with the correct engineering calculations and quality implementation, light steel will continue to hold a significant place in the future of construction technology.

Wall Construction in Light Gauge Steel Structures

Floor Construction in Light Gauge Steel Structures

Step-by-Step Guide to the Construction of Light Gauge Steel Structures: Click

Sound and Thermal Insulation in Light Gauge Steel Structures: Click

UNBAK Youtube Video List: Click