Building components · Openings & Frames
Opening Head
Explains the head as a position combining a structural and a weathering requirement that are commonly resolved by different elements.
Educational reference entry. What this element has to do, and whether any particular arrangement of it is adequate, depends on the whole assembly, the loading, the exposure, local requirements, the manufacturer's instructions and qualified professional design.
Overview
What a head is
The head is the top of an opening. Two things have to happen there: the wall above has to be carried across the gap, and water running down inside the wall has to be intercepted and directed out before it reaches the opening.
The two requirements are usually met by different elements — a lintel carries, a tray and weeps drain — and treating the head as a position rather than as a single component is what keeps both in view.
Boundaries
How it differs from nearby elements
The distinctions that keep this entry from being a restatement of its neighbours.
- It is not a lintel. A lintel is one of the things that may carry the wall at a head, and masonry lintels are a published material entry; the head is the position.
- It is not a cavity tray. A tray is the element draining the head in a cavity wall; the head is where it sits.
- It is not a jamb or a sill, which are the other sides of the same opening with different requirements.
Terminology
Common names and aliases
These names describe the same element. The library keeps one entry per component so that a trade term or a regional name never becomes a second, thinner page.
- head of opening
- opening heads
- head condition
Dependencies
What it depends on
What has to be right elsewhere for this element to do its job.
- What carries the wall above, and how far that support bears into the wall each side.
- How water within the wall is intercepted at this level and directed out.
- How insulation continues across the head, since the structural element commonly crosses the insulation line.
- Whether the frame below is fixed to the head or held clear of it, given deflection of the supporting element.
Considerations
Topics that genuinely apply here
Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.
The head is a horizontal interruption in a wall, and water running down the cavity arrives at it; without a tray and weeps that water tracks inward.
A structural element crossing the wall at the head is a thermal bridge, and it sits directly above a window where condensation is most likely to be noticed.
Whatever carries the wall above delivers concentrated load to the masonry each side of the opening.
The supporting element deflects under load, and a frame fixed tight beneath it can be loaded by that deflection.
Materials
Commonly formed from
Material families this element is commonly realised in. This states common practice only — it is not a statement that any of these materials suits this component in a particular building, which depends on the whole assembly and on qualified review.
Assemblies
Building systems this element is met in
The role this component fills inside each assembly. A role describes what the element does there — it is not a statement that this component suits that system in any particular building.
Junctions
Interfaces this element takes part in
Junctions where the condition between this element and another governs how the construction behaves. These name the junction and the subjects it raises; they are not details, arrangements or approved ways of building.
Frame to Opening Head
Where a frame meets the top of an opening, beneath a structural element that deflects and above which water collects.
Raises: Structural transfer · Moisture · Thermal continuity · Movement
Where it is met
Application contexts
Building contexts where this element is commonly encountered. Association is not recommendation: appearing here does not mean the component suits every instance of that context, or any particular one.
- Opening
Clarifications
Commonly misunderstood
- That a lintel is all a head needs. In a cavity wall the drainage arrangement is equally necessary and is a separate provision.
- That damp above a window is a window problem. It is very commonly a missing or badly formed tray at the head.
Conversations
Questions for qualified professionals
Questions worth asking someone with the project in front of them. This page cannot answer them.
- What carries the wall above this opening, and what bearing does it have each side?
- How is water within the wall intercepted at the head and directed out?
- How does insulation continue across the head?
- Is the frame held clear of the supporting element so its deflection is not transferred to the window?
Go deeper
Related Build Design Hub guides
Planning guidance behind the decisions this element involves.
Preparation
Related planning checklists
Owner-side preparation before the conversation where this element comes up.
What this entry does not do
- No bearing length, lintel type, tray arrangement or insulation detail is stated here.
- Forming or altering an opening in a loadbearing wall is structural work requiring qualified design.
Openings & Frame Elements
The frames, heads, jambs, sills, thresholds and closers that form and finish an opening through a wall.
Browse all openings & frames entries →