5 top tips for installing steel lintels

The correct specification of lintels is crucial, however it is just as important to ensure that each one is installed correctly. Here are five top tips to ensure an issue free installation.

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Before installation begins it is important to confirm that the correct lintel is being used. A comprehensive lintel schedule that provides a detailed description of each lintel, including its location will help prevent any confusion. Catnic’s CLASS service is offered free and provides a single concise document with all the relevant details.

Furthermore, while it might seem obvious, it is essential to store lintels carefully on-site and check that each lintel is not damaged prior to installation. Any damage may affect its performance and could result in serious issues for the building.

The lintel must be installed with a nominal 150 mm bearing area at each end, meaning that the total length should be 300 mm more than the clearspan. The lintel should be fully bedded on bricklaying mortar and level both along its length and across its width. Only full bricks or blocks should be part of the bearing area - lintels should not be placed directly onto part bricks. This bearing area may also need to be increased for applications with extreme structural loads. Where this is the case, seeking advice from the lintel manufacturer is always recommended.

It is crucial to ensure that the loads placed on the lintels are in line with the original specification. As such, it is important to be aware of any concentrated loads where all or a substantial part of the loading is focused. Each concentrated load must be supported over a length of lintel of no less than 200mm. Applying point loads directly to the flanges of lintels should also be avoided.

Furthermore, where the lintel carries an external cavity wall, no more than half of the safe working load should be carried by the outer leaf. Also, before concrete floor loads are applied, make sure the total loads have been checked by a structural engineer or the Catnic technical team..

It is a National House Building Council (NHBC) requirement to apply a damp proof course (DPC) over each lintel to protect it. Many Catnic lintels feature a Duplex Corrosion Protection coating and a unique profile shape that acts as a built-in DPC. Any water that gets into the cavity will transfer across the sloping face of the lintel and be released externally via weep holes. This feature makes installation easier and eliminates the possibility of applying the DPC incorrectly.

In severely exposed locations or where the lintel does not offer a built-in DPC, a separate membrane should be fitted. It should be turned up at the edge to ensure the water is not directed into the cavity. For coastal areas, the use of soffit cladding should also be considered to provide further protection.

It is important that lintels are installed as supplied and not cut or modified without seeking advice from the manufacturer. The Catnic team can provide expert guidance on any technical issues or questions including any alternations to the original specification to ensure that the structural performance is not compromised.

Our recommendation for remediating lintels that have been scratched or are suffering from paint loss or corrosion are as shown below:

• Remove all loose or unsound coatings to a firm edge.
• Prepare corroded areas by blast cleaning or hand prepare.
• Detergent wash all surfaces to remove any dirt or soluble salts
• Lightly abrade old powder coatings then rinse with fresh water and allow to dry.
• Patch prime exposed metal with dry film thickness of 100 microns, followed by a further coat of polyester or epoxy paint (allowing enough drying time between coats).
• Do NOT apply or cure paint systems below 5°C (ideally above 10°C)