Doors & Openings
Framed Openings in Pre-Engineered Steel Buildings
Definition: A framed opening is the steel framework of jambs, a header and sometimes a sill that surrounds a door, window, louver or other penetration in a metal building wall. It replaces the interrupted girts and panels, carries wind load around the opening and gives the opening product a straight, square edge to fix to.
Key facts
- Jambs are usually cold-formed C or channel sections, sized for the wind load from the opening and the girts they support.
- Large door openings often need jambs that run full height to the eave strut rather than stopping at the next girt.
- Jamb base clips are anchored to the slab, so their location must be shown on the anchor bolt plan.
Role in the structure
When a wall is cut for a door or window, the girts that normally span between columns are interrupted and the wall panels lose their support. The framed opening collects the wind pressure acting on the opening product and on the panels above and beside it, and delivers that load to the girts, the eave strut or the foundation. Jambs act as short vertical members that span from the slab to the girt or eave level, the header bridges across the top of the opening, and the trim closes the cut panel edges so the wall stays weathertight.
What parts make up a framed opening?
A typical framed opening has two vertical jambs, a horizontal header across the top and, for windows and louvers, a sill at the bottom. The members are generally cold-formed sections of the same family as the girts, which keeps detailing and connections simple. Clips connect the jambs to the girts above and to the slab or base angle below.
Trim pieces wrap the cut edges of the wall panels at the head, jambs and sill. These jamb, head and sill trims hide the raw panel edge, shed water away from the opening and give a finished appearance. For insulated walls the trim also covers the insulation edge and should be detailed so that moisture cannot enter the wall cavity.
How framed openings carry wind load
Wind acting on a large door is collected by the door guides or frame and passed to the jambs. Each jamb then behaves like a vertical beam spanning between its supports, so its required size depends on the opening width it serves, the height it spans and the design wind pressure for the site. Wide openings for industrial doors therefore need deeper or doubled jambs, and sometimes a hot-rolled or built-up section.
The header picks up the panels and girts above the opening and delivers that load to the jambs. Where the opening reaches close to the eave, the header may be omitted and the eave strut used instead. All of these decisions are confirmed by the project engineer to the governing code, taking into account whether the door is assumed open or closed during a design wind event.
Coordinating openings with bracing and columns
Openings must be located so they do not clash with wall bracing, columns or downspouts. A door placed in a braced bay may require portal bracing or a moment frame in place of diagonal rods. Early coordination of door and window locations with the building layout avoids late changes to the bracing system.
Openings in endwalls also interact with endwall columns. If a door is wider than the endwall column spacing, a column may need to be removed and replaced with a header beam, or the endwall changed to a rigid frame. These are normal options but they affect price and should be decided before engineering starts.
Materials & coatings
- Cold-formed C or channel jambs and headers from galvanized or primed high-strength steel strip.
- Hot-rolled channels or built-up sections for very wide or tall openings where cold-formed members are not sufficient.
- Pre-painted steel jamb, head and sill trims matching the wall panel color.
- Slab clips and anchors for jamb bases, with sealant and closures at the panel edges.
Design considerations
- Design wind pressure on the opening product and whether the opening is treated as open or closed in the wind design.
- Width and height of the opening and the span of each jamb between supports.
- Deflection limits suited to the door or window manufacturer requirements.
- Clearance between openings and wall bracing, columns, downspouts and utilities.
Fabrication
- Jambs and headers are cut to length and punched to match girts, clips and the opening product.
- Members are marked with the opening reference and wall line for site identification.
- Trims are roll-formed or press-braked from the same coated coil as the wall panels.
Erection
- Set jamb base clips on the slab at the dimensions shown on the anchor bolt plan.
- Erect jambs plumb and connect them to girts or eave strut before installing the header.
- Check the clear opening size and diagonals before wall panels are installed.
- Install head trim before jamb trims so that water laps outward and downward.
Inspection & quality
- Verify clear opening dimensions, plumbness and squareness against the drawings.
- Confirm all clips, bolts and slab anchors are installed and tight.
- Check trims are sealed and lapped correctly, with no open panel ends.
What to include in your RFQ
- Type, location and clear size of every opening, including wall line and elevation from finished floor.
- Opening product type, so jamb sizes and fixings suit the door, window or louver.
- Whether the opening is to be framed only or framed and supplied with the product.
- Any openings planned for the future that should be pre-framed now.
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 a framed opening be added after the building is erected?
Yes. Jambs and headers can be installed later and the panels cut and trimmed on site. The engineer should confirm that the existing girts and bracing can accept the change, and the wall must be resealed carefully.
Why do large door jambs run all the way to the eave?
A wide door collects a large wind load. Running the jamb to the eave strut gives it a stiff top support and avoids overloading an interrupted girt. The engineer decides the arrangement for each opening.
Does a framed opening include the door or window?
Not necessarily. Framing can be supplied alone for products bought elsewhere, or together with doors and windows. The RFQ should state which is required so the framing suits the product.
Engineering content is general guidance. Every World Steel building is designed by qualified engineers to the code and loads of the project.
