A head rail (Dutch: bovendorpel) is the top horizontal member of a window or door frame. It spans the width of the opening and provides structural support to the frame while transferring loads from above to the vertical side members (stiles or jambs).
Construction and materials
Head rails are made from various materials depending on the frame type:
- Timber — traditional choice, often hardwood for exterior frames. The head rail is typically joined to the stiles with mortise-and-tenon joints or dowels.
- PVC (uPVC) — common in modern window frames. The head rail is a hollow extruded profile reinforced with a steel core for rigidity.
- Aluminium — used in commercial and contemporary residential projects. Aluminium head rails are extruded profiles with thermal breaks to prevent heat loss.
- Steel — found in heritage and industrial-style frames, offering slim sightlines and high strength.
The cross-section of a head rail includes grooves or rebates that hold the glass pane or glazing bead in place, as well as channels for weather seals and drainage.
Difference from a lintel
A head rail should not be confused with a lintel. The head rail is part of the frame itself, while a lintel is the structural beam built into the wall above the opening. The lintel carries the weight of the masonry or structure above; the head rail only supports the frame and glass. Both work together to create a solid, weathertight opening.
Application in construction
When installing a window or door, the head rail is positioned at the top of the rough opening and fixed to the lintel or wall above. Proper shimming and sealing around the head rail are essential to prevent water ingress and air leakage. In renovation projects, a damaged or rotting timber head rail is one of the most common reasons for replacing an entire frame.
Related terms
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