Catnic Steel Box Lintel for External Solid Walls - CN71A
The Catnic CN71A Solid Wall Lintel is perfect for exterior solid walls. This box profile lintel is...The Catnic CN71A Solid Wall Lintel is perfect for exterior solid walls. This box profile lintel is manufactured from galvanised steel and powder-coated for extra protection. Its box profile design resists twisting during construction and is designed to carry a full load of wet masonry as soon as it is installed. It features Duplex Corrosion Protection, a built-in plaster key, DPC, and integral insulation. Formed from galvanised steel then powder coated, it is easy to use and designed for continuous insulation. Standard lengths are available up to 3000mm, and in increments of 300mm for lengths above 3000mm. The lintel is designed for openings up to 2400mm with a minimum bearing of 150mm at each end. A 900mm lintel weighs just under 9kg and supports 29kN, while a 2700mm lintel weighs less than 26kg and supports 20kN. It is designed to take two brick courses on the front flange, offering a high-performing solution for difficult openings.
Best current price£33.68from Materials Market Trading UK Ltd
The Catnic CN71A Steel Box Lintel is an essential component for builders and contractors constructing external solid walls, offering superior structural support and continuous insulation. Its robust design ensures immediate load-bearing capabilities even with wet masonry, though precise installation is crucial for harnessing its full potential and ensuring long-term performance. This guide will walk you through its features, optimal use, and care to help you maximize its value in your construction projects.
All features
Model Part Number
CN71A
Brand
Catnic
Extended Product Information
FAQs
What type of walls is the Catnic CN71A Lintel designed for?
It is specifically designed for use in external solid walls, providing robust structural support and continuous insulation.
What does 'Duplex Corrosion Protection' mean?
Duplex Corrosion Protection refers to the dual-layer protection of galvanised steel combined with a powder-coated finish, offering superior resistance against rust and environmental corrosion.
How much bearing is required for proper installation of the lintel?
A minimum bearing of 150mm is required at each end of the lintel on the supporting masonry for optimal load distribution.
Can I cut the Catnic CN71A Lintel to a specific size on site?
Cutting the lintel on site is generally not recommended as it can compromise the structural integrity, remove the corrosion protection, and void any warranty. It is best to order the correct length for your opening.
Does this lintel require temporary propping during the construction process?
The box profile design allows it to carry a full load of wet masonry as soon as it's installed, significantly reducing the need for extensive temporary propping. However, for very long spans or extremely heavy loads, temporary support until the mortar cures might be considered good practice.
What is the maximum opening width this lintel can span?
The Catnic CN71A is designed for openings up to 2400mm using standard lengths. Longer custom lengths are available in increments of 300mm for larger spans.
What is the purpose of the integral insulation in the lintel?
The integral insulation helps to prevent cold bridging at the opening, thereby improving the overall thermal performance of the wall and contributing to better energy efficiency for the building.
Troubleshooting
Lintel appears to be twisting or deflecting after installation.
Verify that the lintel has the required minimum bearing of 150mm at each end. Ensure the masonry above is evenly distributed and that adequate propping was used, if necessary, during the initial setting of the mortar. Consult a structural engineer if the issue persists.
Signs of dampness or cold spots around the lintel opening.
Check that the integral insulation is intact and not damaged. Ensure the DPC (Damp Proof Course) is correctly installed and integrated with other damp-proofing measures in the wall. Confirm that all joints around the lintel are properly sealed to prevent moisture ingress and cold bridging.
Corrosion spots appearing on the lintel surface.
While protected by Duplex Corrosion Protection, severe scratches or impacts during handling or installation can expose the underlying steel. Clean the affected area, ensure it is dry, and apply an appropriate anti-corrosive primer followed by a compatible topcoat to restore protection.
Pros and Cons
Pros
Exceptional structural integrity and immediate load-bearing capability.
Enhanced corrosion resistance for extended product lifespan.
Improved thermal efficiency with integral insulation, reducing cold bridging.
Simplifies construction with built-in plaster key and DPC.
Resists twisting, maintaining stability during building.
Suitable for challenging openings due to high load capacity.
Cons
Requires precise measurements for optimal fit and performance.
Heavier than some alternative lintel materials for longer spans, potentially requiring more lifting assistance.
Specifically designed for external solid walls, limiting its application versatility.
Damage to the powder coating can compromise corrosion protection if not repaired.
Installation requires adherence to specific masonry and structural best practices.
Setup, Compatibility & Care
Setup Instructions
Preparation: Ensure the opening is clean, level, and plumb. The lintel should be placed with the DPC (damp proof course) side facing outwards, typically indicated by a label or marking.
Bearing: Place the lintel ensuring a minimum bearing of 150mm at each end on the supporting masonry. Adequate bearing is crucial for distributing the load effectively.
Positioning: The lintel is designed to carry two brick courses on the front flange. Ensure it is correctly oriented to accommodate this.
Masonry: Begin laying masonry on the lintel immediately. The box profile is designed to take the full load of wet masonry as soon as it is installed.
Propping: While the CN71A is designed for immediate load-bearing, for very long spans or unusually heavy loads, temporary propping might still be considered good practice until the mortar has fully cured. Consult local building codes and engineering specifications.
Compatibility
Wall Type: Specifically designed for external solid walls.
Opening Sizes: Suitable for openings up to 2400mm with standard lengths. Longer lengths are available for larger spans.
Materials: Compatible with standard brick and block masonry construction.
Care & Maintenance
The Catnic CN71A Lintel is largely maintenance-free due to its galvanised steel construction and powder-coated finish, offering robust Duplex Corrosion Protection.
During handling and installation, avoid scratching or damaging the powder coating as this could expose the galvanised layer and potentially compromise long-term corrosion resistance. If significant damage occurs, it should be repaired promptly with a suitable protective coating.
Periodically inspect exposed areas during routine building maintenance to ensure the lintel remains in good condition and there are no signs of physical damage or excessive wear.
Materials Market Trading UK Ltd£33.68Visit shop 
Travis Perkins£56.70Visit shop 
