Fixing and buying guide
S/K1501800 KEYSTONE S/K-150 X 1800mm Standard Cavity Wall Lintel
What this product is and who it is for
This is a standard cavity wall lintel manufactured by Keystone. The S/K-150 designation indicates it is designed for a 150mm cavity width, making it compatible with typical UK cavity wall construction. The 1800mm length suits medium-span openings. It is intended for professional builders, structural engineers, and competent DIY users installing windows, doors, or other openings in cavity masonry walls.
- Load-bearing steel lintel for cavity walls
- Designed for 150mm cavity width
- 1800mm span length
- Suitable for windows, doors, and similar openings
Compatibility and sizing
Before purchasing, confirm that your cavity wall width is 150mm and that your opening span does not exceed 1800mm. Check your building plans or measure the cavity width on site. If your opening is longer than 1800mm or your cavity is a different width, you will need a different lintel size. Consult structural drawings or a surveyor if unsure of the correct specification.
- Cavity width must be 150mm
- Maximum span 1800mm
- Verify opening dimensions before ordering
- Check building regulations compliance for your application
Pre-installation checks
On delivery, inspect the lintel for damage, corrosion, or deformation. Store it flat and dry on site. Before fixing, ensure the cavity is clean and free of debris, mortar droppings, and obstructions that could prevent proper seating. The supporting masonry on both sides of the opening must be sound and capable of bearing the load. If the lintel will be exposed to weather during construction, protect it from prolonged moisture.
- Inspect for damage or corrosion on arrival
- Store flat and protected from weather
- Clear cavity of debris and mortar droppings
- Confirm supporting masonry is sound and level
Installation and support
The lintel must be bedded level on a full mortar bed on both leaves of the cavity wall. Ensure adequate bearing length on each side of the opening, typically a minimum of 150mm on each support. The lintel should be installed before the masonry above the opening is built. Once positioned, build up the masonry carefully to avoid eccentric loading. Allow mortar to cure fully before applying significant load.
- Bed on full mortar bed on both cavity leaves
- Minimum 150mm bearing on each side
- Install before building masonry above
- Allow mortar to cure before loading