Secondary Framing
Eave Struts in Metal Building Construction
Definition: An eave strut is a cold-formed steel member, often a C-section with a sloped top flange, placed at the junction of the side wall and roof. It supports the first edge of the roof panels and the top of the wall panels, and acts as a strut in the bracing system.
Key facts
- The top flange is commonly bent to match the roof slope.
- It supports the gutter, eave trim and eave closures.
- It acts as a longitudinal strut in the bracing system.
- Usually bolted to the column cap or rafter end plate region.
- Spans between frames like a purlin, often as a simple span.
Role in the structure
The eave strut forms the corner of the building envelope. It receives roof panel loads at the eave and wall panel loads at the top, and transfers them to the frames. In the longitudinal direction it carries compression and tension from the roof and wall bracing, connecting braced bays to the rest of the frame line.
Why does the eave strut have a sloped flange?
The roof panels must bear evenly on the eave member. Bending the top flange to match the roof slope provides a full bearing surface and a clean line for fasteners and closures.
The vertical web provides a flat face for the top of the wall panels, so one member serves both surfaces neatly.
How does the eave strut work in the bracing system?
Roof and wall bracing deliver longitudinal forces from wind on the endwalls or from seismic action. The eave strut carries these forces along the building line between braced bays and unbraced frames.
When acting as a compression strut, the eave strut must be checked for buckling between frames. Where forces are large, a heavier section or additional struts may be used.
How does the eave strut support gutters?
Eave gutters are typically fixed to the eave strut with brackets and straps. The strut supports the gutter weight, water load and any debris, and provides the line for the eave trim.
For heavy rain regions or large roof areas, the gutter size and support spacing should be confirmed with the drainage design.
Materials & coatings
- Cold-formed C-section with sloped flange in galvanized or zinc-aluminum coated steel.
- Primed steel for protected conditions.
- Galvanized clips and bolts.
Design considerations
- Roof and wall loads at the eave.
- Axial forces from bracing and seismic action.
- Gutter, trim and snow guard loads.
- Match of flange slope to roof slope.
- Connection to frame and bracing points.
Fabrication
- Roll-form the eave strut with the flange set to the roof slope.
- Punch holes for frame, bracing and gutter connections.
- Label by side wall and bay.
Erection
- Install with the first purlins once frames are plumbed.
- Check alignment along the eave line.
- Bolt bracing connections before cladding.
Inspection & quality
- Verify slope and straightness of the eave line.
- Confirm bracing and frame connections.
- Check gutter bracket spacing.
What to include in your RFQ
- Roof slope and eave detail.
- Gutter type and size.
- Eave canopy or roof extension at the side wall.
- Snow conditions at the eave.
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
Is an eave strut the same as a purlin?
It is similar in material but placed at the eave, supports both roof and wall panels and usually acts as a bracing strut.
Can the eave strut support a canopy?
Light canopies can be supported if designed for it. Larger canopies usually connect directly to the main columns.
Why are eave struts sometimes heavier in braced bays?
They may carry higher axial forces near bracing, so the engineer selects a stronger section there.
Engineering content is general guidance. Every World Steel building is designed by qualified engineers to the code and loads of the project.
