Structural Cold-Formed / Light-gauge Studs are used in axial load-bearing walls, curtain walls, interior partitions, floor joists, and roof trusses. For use in commercial, industrial, and residential proposes depending on code regulations sometimes steel is required.
Table of Contents
Sizes and Metal thicknesses
- Web sizes are: 3-1/2” (350S), 3-5/8” (362S), 4” (400S), 5-1/2” (550S), 6” (600S), 8” (800S), 10” (1000S), 12” (1200S), 14” (1400S)
- Flange stud seizes of 1-5/8”, 2”, 2-1/2”
- Metal thickness for structural application: 97 mils *one thousandth of an inch (12 gauge) the thickest, 68 mils (14 gauge), 54 mils (16 gauge), 43 mils (18 gauge), and 33 mils (20 ga).
- Coating: All US Frame Factory Steel is G90, meaning the sheet coating of 0.90 oz/square foot. This is the total weight of Zinc on both sides of the sheet per square foot.
- Our submittal sheets for the most common sizes are 600S162-43, 600T200-43, 400T200-43, 400ST162-43, 362T200-43, and 362S162-43.
Interior steel stud walls: Sizing
- Load-bearing capacity: You’ll need to determine the load that the wall will need to support, including the weight of the wall itself, any additional finishes (e.g. drywall, plaster), and any other loads (e.g. shelves, cabinetry). This will help you determine the minimum size and thickness of the structural studs required. According to the International Building Code, interior (non-load bearing) walls must be built to handle an interior pressure lateral load of at least 5 psf perpendicular to the wall. For walls spanning many floors with several exterior openings, loads of 7.5psf to 10psf are used. Clarkdietrich has a helpful table. However their most useful tool is the structural stud look up. You simply enter in your wall height and desired thickness. Note for stud flange the most accessible is almost always 1-5/8″ flange.
Exterior Curtain Walls: Sizing
Exterior curtain are made of structural studs in commercial or industrial projects. Their purpose is to support exterior cladding such as brick, glass, cladding, and stucco. The key sizes factors to look for are:
- Local building code requirements for size and strength
- Wind Loads: The size of the curtain wall should be determined based on the wind loads that the wall will be subjected to. This will involve performing wind load calculations to determine the size and strength of the wall required to resist the wind loads.
- Thermal performance and the size and thickness required to meet desired insulation values.
- Structural support and the size and strength required to hold the wall in place.
- The weight of exterior cladding such as stucco.
SteelNetwork has a nice page where excisable framing tables starting on page 17. I recommend using this one for looking up steel sizes for Curtain Walls.
Floor Joist Sizing
The International Building Code (IBC) and American Iron and Steel Institute (AISI) both provide guidelines for which metal stud floor joists to be placed. The spacing of the metal studs is also important. The IBC and AISI both recommend a maximum spacing of 24 inches on center for metal studs. BMP-Group has a useful table for floor joist sizing. I also made an estimator to give you the lengths of floor joists.
Metal Stud Screw Sizing
AISI S100-12 North American Specification for the Design of Cold-Formed Steel governs the screw capacity utilized in structural elements. Important factors are number of screws, pullover values. We’ve only ever used single #12 screws for each joint or double #10 screws in builds which
Structural Metal Header Sizing
The American Iron and steel Institute has a great deep dive into box beam design and web stiffeners. There are two types of headers, L headers, and Box Headers. They discuss the advantages of each one starting on page 32.
To have a full sizing table starting on page 79 provided by Canadian Sheet Steel Building Institute.
Stud bracing
Stud bracing is applied for exterior Curtain walls and interior walls frequently adding a lot of sheer strength. This can add a lot of strength without increasing the gauge of studs. Applications for metal stud bracing are either center stud clips with a strap going though the center or a 2″ metal strap run on the wall face screwed into the flanges.
- For exterior Curtain wall design the is created by Sampson Strong-tie in their page about stud bracing for exterior curtain walls. Half way into the article you can see their sizing table for their center clip stud brace.
- This is a table studs with framing based on 12″ O.C, 16″ O.C, 24″ O.C for interior walls.
Application Example
This small job that has elements discusses, different gauge studs, some 6″ walls. The trusses are structural 20 gauge (362S162-33), the exterior curtain load baring walls are 18 gauge(350S162-43), the headers are made of 6″ 16 gauge (600S162-52) and 350T162-54 track. There is also stud bracing made of 2″ 18 gauge stud bracing. We also have X bracing made of 7.5″ 18 gauge flat strapping. See the 3D Matterport below. These are the structural drawings for this particular house.
CAD and programs for design
CFS-Designer (Cold-Form Steel Desginer) is a program created by Sampson Strong-tie that is basically computerized data base of span charts. You can download a free trail and experiment with a variety of different loads and spans.
US Frame Factory
Thank for checking out our article. We are a small scale roll-form operation in South Louisiana. The whole purpose of this page is simply to share resources we found with builders.