Drywall metal studs, or steel studs, are non-combustible framing components used in constructing interior walls and ceilings. They’re designed as a stiff and easy mounting option drywall and other interior interior panels. The metal offers mold & fire resistance, sound suppression, and consistent dimensions, making them ideal for commercial and residential projects.
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Drywall Metal Studs Profile
The stud is shaped like the letter “C” or “U,” with one open side. The U-stud has two flange extending outward from the web, while the C-stud has both flanges turned inward towards each other. All Metal drywall studs are made from galvanized steel with a corrosion resistant zinc coating. Web sizes range from 1.62″ to 6″ with flange sizes fixed at 1.25″. There is a curve in the bottom web of the track so studs don’t get stuck stacking in eachother.
The most common metal thickness for drywall studs is EQ20 gauge(Equivalent 20 gauge0). This means that the metal in the stud is either 23 mils thickness and 33-50 KSI, or 18 mils and 70 KSI. The metal coating is G40 or EQG40. G40 means it means that there is approximately 0.4 ounces of zinc coating per square foot of the steel’s surface. EQG40 is means while the studs are protected in a different method than zinc coating but still an equivalent amount of corrosion protection.
For interior framing sizes come in 1-5/8″ inches, 2-1/2″ inches, 3-5/8″ inches, and 6″. 3-5/8″ are the most common, used for standard interior partitions the width is wide enough to accommodate sound dampening/insulation and standard electrical wiring. 6″ is used for bathroom walls, as it accommodates the bigger piping used for plumbing.
Drywall studs are punched to accommodate wiring, pipes and bracing. The standard punch width is 1.5″ inches. The punch profile varies but always a small tab at the bottom. The East Coast drywall metal stud punch spacing is 12″ from the leading end and then 48″ o.c. West Coast spacing is 24″ from the leading end and then 24″ o.c.
Drywall Stud Hight Tables
While not load baring there have been tests run on drywall studs to recommend the height studs can go with acceptable wall deflection. This is based on the 5/8″ Gypsum board on both sides of the wall. For a common 362S125-18 70 KSI stud walls can usually go 16’8. According to “ASTMC645-18 Standard Specification for Nonstructural Steel Framing Members” the framing walls should be limited to a lateral load of not more than 10lb/sf. Meaning whatever sheathing you’re hanging on the wall should be total more than 10 lbs/sf.
Above is a table estimating from online data the wall heights you can achieve with non-structural drywall studs under expressed load conditions. The products vary on the market and the recommended height values will change based on which stud you buy.
Knurling and Rib/Ridge Technology
Most stud and track system incorporates a textured flange with knurled patterns and reinforcing ribs. Knurling refers to the creation of small ridges on the flange, serving to prevent screws from shifting or moving. This doesn’t effect stud strength.
Ribbing creates grooves in a stud which allows screws to catch and manufacturers and marginally increases strength. The ribs/ridges mostly decrease the likely hood of the studs twisting. The image below is a US Frame Factory designed stud with ridge corners to catch the screw and increase the strength.
Drywall metal stud framing tools
Interior drywall metal stud framing is actually easier than wood framing. The metal is easy to cut with tin snips and bend and manipulate. Clean-up is far easier and you don’t need a chop saw like wood.
- Measuring and Layout Tools: Tape Measure, Carpenter’s square, Chalk line/laser level for marking layout lines
- Cutting Tools: Tin snips/aviation shears for cutting metal studs/tracks
- Fastening Tools: Drill and Self-tapping screws designed for metal framing
- Leveling and Plumb Tools: Bubble level/digital level to ensure that the metal studs are level and straight
Technical Data and Resources
Submittals online for technical data are easily found and typically give similar values. These submittals include values like:
- Gross Section Properties: Cross Sectional Area, Moment of Inertia, and Radius of Gyration
- Effective Section Properties: Moment of inertia for deflection, and Allowable bending moment.
- Torsional Properties: St. Venant torsion constant, Torsional flexural constant
Technical Data and links
- North American Standard for Cold-Formed Steel Framing – Nonstructural Members AISI-S220-15-S220-15-C_s
- Standard Specification for Nonstructural Steel Framing Members ASTMC645