Cavity Wall Structural Lintel L1 /S 150mm – 1200mm ( SD )

The Cavity Wall Structural Lintel L1/S 150mm – 1200mm (SD) by Stock Gap Limited is a standard-duty galvanised steel lintel engineered to bridge window and door openings in cavity wall construction. Designed for cavity widths of 150–165mm, it delivers reliable structural support for both the inner and outer leaves of masonry walls, making it a go-to choice for builders, contractors, and confident DIYers working on residential and commercial projects across the UK.

Key Features and Specifications

• Length: 1200mm
• Cavity width: Suitable for 150–165mm cavity walls
• Outer leaf: 102mm (brick or blockwork)
• Inner leaf: 100–115mm blockwork
• Material: High-quality galvanised mild steel to BS EN 10346:2009 (DX51D + Z600)
• Duty rating: Standard duty (SD) — supports uniform masonry loads, timber floor loads, and distributed roof loads
• Insulation: Factory-fitted expanded polystyrene (EPS) between flanges to minimise thermal bridging
• Plaster key: Perforated inner flange for secure plaster adhesion
• DPC: Integral damp-proof course
• Fire performance: Tested to BS 476: Part 20: 1987
• Structural performance: Tested to BS 5977 Part 2: 1983 and BS EN 845-2:2003
• Finish: Post-fabrication galvanising with corrosion-resistant treatment to all cut edges

Applications

• Spanning window openings in new-build cavity wall construction
• Supporting masonry above door openings in brick and block walls
• Residential extensions, loft conversions, and new-build housing
• Commercial and light-industrial masonry cavity wall projects
• Replacement of failed or undersized lintels during renovation works
• Fair-faced inner leaf masonry applications

Why Choose This Product

The Stock Gap Limited Cavity Wall Structural Lintel L1/S 150mm – 1200mm (SD) meets UK Building Regulations thermal performance requirements, helping projects satisfy Part L energy-efficiency standards without additional remedial work. The factory-fitted EPS insulation eliminates cold bridging at the lintel zone — a common weak point in cavity wall construction. Galvanised steel construction ensures long-term corrosion resistance, while the integral plaster key and DPC speed up installation and reduce on-site labour. Sold individually, it is equally suited to single-unit DIY purchases and bulk trade orders.

Delivery in and Around London

Stock Gap Limited offers delivery of the Cavity Wall Structural Lintel L1/S 150mm – 1200mm (SD) to customers throughout London and the surrounding region. Inner London boroughs served include Croydon, Lewisham, Southwark, Camden, and Hackney, with Greater London coverage extending to Enfield, Bexley, Redbridge, and Barnet. Deliveries also reach the surrounding counties of Kent, Essex, Surrey, and Hertfordshire. Trade quantities are welcome — contact us for volume pricing and scheduled site deliveries.