TB/07 – Window Head with Proprietary Steel Cavity Wall Lintel

This window head detail illustrates a typical junction within an insulated masonry cavity wall using a proprietary galvanised steel cavity wall lintel.

The drawing is intended for architectural designers, building professionals, contractors, developers and self-builders preparing coordinated Building Regulations information or a project specification.

For the corresponding lower junction, see the accompanying sill drawing. The wider structural context is set out in Approved Document A.

The detail shows:

• External brickwork and Celcon Solar aircrete block inner leaf
• Plasterboard on dabs with skim finish
• Proprietary insulated galvanised steel cavity wall lintel
• Indicative IG HT/S+ 110 lintel without a continuous base plate
• Insulation beneath the lintel soffit
• Minimum thermal resistance for soffit insulation
• Cavity tray positioned over the lintel
• Stop-end and weep-vent requirements
• Continuity of cavity-wall insulation at the window head
• Minimum window-frame overlap
• Internal airtight and external weather-resistant sealing
• Minimum lintel end-bearing requirements
• SAP junction reference E2
• Calculated psi value of 0.294 W/m·K

The accompanying specification notes cover lintel selection, load capacity, end bearings, cavity trays, stop ends, weep vents, insulated cavity closers, cavity cleanliness, moisture protection, airtightness and weather sealing.

What This Window Head Detail Includes

• One downloadable PDF construction drawing
• A3 landscape sheet
• Drawn at 1:10 scale when printed at 100% on A3 paper
• Drawing reference: TB/07
• Detail title: Window Head with Proprietary Steel Cavity Wall Lintel

Important Information

This is a standard construction detail intended to provide general design and specification guidance. The lintel shown is indicative and must be checked for suitability for the actual wall construction, cavity width, opening size, masonry loads, floor loads, roof loads and any other imposed loading.

The final lintel type, length, load capacity, end bearings and installation requirements must be confirmed by the lintel manufacturer or a suitably qualified structural engineer. Proprietary components must be installed in accordance with their current certification and manufacturer’s instructions.

The stated psi value applies only where the illustrated geometry, materials, lintel and insulation arrangement are followed. It should be checked for use within the project’s SAP or thermal-bridging assessment.

The drawing does not include project-specific lintel calculations, structural design, window specification, SAP assessment or Building Regulations approval. Purchasing or using the detail does not guarantee approval by Building Control.

The PDF is supplied for use by the purchaser on their own projects. It may not be resold, redistributed, shared as a standalone product or reproduced for commercial resale without written permission.