Cavity lintels are key structural components in modern construction. They span openings in cavity walls, supporting the load above while maintaining thermal insulation. These lintels bridge the gap between the inner and outer leaves of brickwork.
Cavity lintels come in various materials and designs to suit different projects. They offer superior load-bearing capacity and thermal performance.
What Are the Different Types of Cavity Lintels?
Cavity lintels come in several types, each suited for specific applications.
- Steel cavity lintels: Durable and strong, ideal for heavy loads
- Concrete cavity lintels: Offer excellent fire resistance and load-bearing capacity
- Timber cavity lintels: Suitable for lighter loads and provide natural insulation
- Insulated cavity lintels: Feature built-in insulation for thermal performance
- Box lintels: Provide additional support for wider openings
- Single leaf lintels: Used when only one leaf of the cavity wall needs support
How Do I Determine the Correct Length for a Cavity Wall Lintel in Various Openings?
Determining the correct length for a lintel for cavity wall openings is important for proper support. Start by measuring the clear span of the opening. Add a minimum of 150mm bearing at each end. Also, consider the wall thickness and for wider openings or heavier loads, increase the bearing length.
4 Common Mistakes to Avoid When Fitting a Cavity Lintel
- Poor bearing: Ensure proper support at each end of the lintel
- Incorrect positioning: Place the lintel at the right height and level
- Overloading: Choose a lintel with adequate load-bearing capacity for the structure
- Ignoring thermal bridging: Select insulated lintels when necessary to maintain thermal performance
What Are the Best Practices for Weatherproofing Around a Cavity Wall Lintel?
Effective weatherproofing around cavity wall lintels is essential for preventing water ingress. Install a DPC above and below the lintel. Make sure the DPC extends beyond the lintel ends and is properly lapped with the wall DPC.
Use weep holes at regular intervals to allow water drainage and apply a high-quality sealant around the lintel edges. Consider using stop ends on the lintel to direct water away from the inner leaf.
How Does Thermal Performance Vary Between Different Types of Cavity Lintels?
Thermal performance varies significantly among cavity lintel types. Steel lintels typically have lower thermal resistance, potentially creating cold bridges. Concrete lintels offer better insulation but can still contribute to heat loss.
Overall, an insulated lintel for cavity wall structures provides the best thermal performance. They feature built-in insulation to minimise heat transfer. Also, timber lintels offer natural insulation properties.