Secondary Framing
Wall Girts for Pre-Engineered Steel Buildings
Definition: A wall girt is a horizontal secondary member, usually a cold-formed Z or C section, that spans between columns and supports the wall panels. Girts collect wind pressure and suction on the walls and transfer it to the main frame and endwall columns.
Key facts
- Girts are commonly Z-sections lapped for continuity or C-sections for simple spans.
- Spacing depends on wall panel strength and wind pressure.
- Girts can be by-framed (outside the columns) or flush-framed (within the column depth).
- Sag rods or straps may support girt weight and reduce sag.
- The first girt is often positioned above a masonry dado or curb.
Role in the structure
Wind acting on the wall panels is carried by the girts in bending to the columns. Girts also support the weight of the wall cladding, restrain the outer column flange, and provide connection points for flange braces that stabilize the inner column flange. Around doors and windows, girts frame the opening heads and sills.
What is the difference between by-framed and flush-framed girts?
By-framed girts pass outside the column flange and can be continuous over several bays. They are economical and simple to erect, and the wall line sits slightly outside the frame.
Flush-framed girts are set within the column depth, connected to the web with clips. They increase usable interior width or suit masonry walls, but are simple spans and generally heavier.
How do girts handle wind pressure and suction?
Positive pressure pushes the panel onto the girt outer flange. Suction pulls it away, putting the inner flange in compression, which is restrained by bridging, sag rods or liner panels where present.
Higher wind zones at corners require closer spacing or heavier girts. The engineer sets the arrangement to the governing loading code.
How are openings framed in the wall?
Girts are interrupted at doors and large windows. Jamb members carry the girt ends and the door wind loads, while head and sill members frame the top and bottom of the opening.
Opening sizes and positions should be confirmed before secondary framing is detailed so that girts can be located clear of heads and sills.
Materials & coatings
- Cold-formed Z or C sections in galvanized or zinc-aluminum coated structural steel.
- Primed uncoated steel in protected interior conditions.
- Galvanized bolts and clips.
Design considerations
- Wind pressure and suction, including edge and corner zones.
- Wall panel span capability and girt spacing.
- By-framed versus flush-framed arrangement.
- Opening layout and jamb framing.
- Deflection limits for brittle finishes or glazing.
- Interaction with masonry dados or precast panels.
Fabrication
- Roll-form girts to profile and length.
- Punch holes for laps, clips, sag rods and flange braces.
- Bundle by wall elevation and label pieces.
Erection
- Fix girts after columns are plumbed and bracing is installed.
- Install sag rods or straps to keep girts level.
- Check straightness before fixing wall panels.
Inspection & quality
- Check girt sizes, spacing and laps.
- Verify opening framing positions.
- Confirm flange braces at girt locations.
What to include in your RFQ
- Wall panel type and orientation.
- Masonry dado height, if any.
- Door and window sizes and positions.
- Preferred by-framed or flush-framed girts.
- Site wind data.
3D model & IFC of this component
Rotate the model, isolate the component and download its IFC4 file for your BIM coordination model.
IFC entity: IfcMember. Illustrative geometry for coordination and learning. Final member sizes come from the project design.
Frequently Asked Questions
Can girts support wall-mounted equipment?
Only light items unless the load is included in the design. Heavier items need supplementary framing.
Why are girts closer together near the corners?
Wind suction is higher at building corners, so the girts are spaced closer or made heavier there.
Do flush girts cost more?
Usually yes, because they act as simple spans and need clips at each column, but they can save interior space.
Engineering content is general guidance. Every World Steel building is designed by qualified engineers to the code and loads of the project.
