Steel Lintels | Installation Guide
- Steel Lintels should be installed with a minimum end bearing of 150mm, bedded on mortar and levelled along its length and across its width.
- The masonry above the lintel should be built in accordance with BS EN 1996-2:2006.
- Raise the inner and outer leaves simultaneously to avoid excessive eccentricity of loading, with a maximum height difference of 225mm (Masonry should be laid on a mortar bed and all perpendicular joints should be filled.)
- Allow the mortar to cure before applying floor or roof loads (Temporary propping beneath a steel lintel is practised to facilitate speed of construction).
- The NHBC recommend a damp proof course (DPC) or cavity tray should be installed over all openings in external cavity walls.
- When installing concrete floor units or other heavy components above a lintel, care should be taken to avoid shock loading and floor units should not be dragged into position. Masonry immediately above the lintel should be allowed to cure.
- Point loads should not be applied directly onto lintel flanges. Steel Lintels should have a minimum of masonry 150mm high between the flange and the application level of any form of loading. Consult Keystone’s technical department if applying a point load above lintels.
- The external lintel flange must project beyond the window/door frame and it is recommended that a flexible sealing compound is used between the underside of the lintel flange and the frame.
- When the underside of a lintel is exposed, its appearance can be enhanced by the addition of lintel soffit cladding.
- Do not cut lintels to length or modify them in any way without consulting an Keystone engineer.
Ensure lintel is level along its length.
Ensure lintel is level along its width.
Lintel Position within a Cavity Wall
- Lintel should be centred in the cavity and the distance between lintel up-stand within the cavity and masonry must not exceed 8.5mm
- Masonry should not overhang any flange by more than 25mm.
Propping a lintel is sometimes practised to facilitate speed of construction. It should only be introduced after initial masonry load has been applied to the lintel.
When propping a lintel, a horizontal timber plank should be placed along the underside of the lintel and suitable* props secured into place at maximum 1200mm centres.
* Suitability of props is the responsibility if site management.
Damp Proof Course DPC
In accordance with BS EN 1996-2:2006 and NHBC requirements all external wall lintels MUST be installed with a flexible damp proof course with the exception of those adequately protected by an eaves overhang or similar form of protection. Stop ends should be provided as specified by BS EN 1996-2:2006 and the NHBC, to avoid moisture entering the cavity near the reveals. Proprietary stop ends should be used or alternatively the DPC should extend to the edge of the external lintel flange and 50-150mm beyond the end of the lintel (depending on coursing) to allow formation of an integral stop end at a suitable perpendicular joint.
Provide weep holes at a maximum of 450mm intervals (at least two per opening) with fair-faced masonry.
Consider the use of soffit cladding for all coastal sites.
- Keystone steel products are produced from galvanized steel plate which may present sharp edges. Suitable personal protective equipment should be worn at all times during handling and installation. Gloves should be worn to avoid injury from any sharp edges
- When lifting or carrying a lintel undertake a personal risk assessment paying attention to the size and weight of the product. To avoid lifting strains any lintels other than the shortest lengths should be lifted by at least two people or alternatively by mechanical means.
- Do not use damaged lintels.
Lintels should be stored on wooden skids on flat ground. Keystone recommends that they are stored one bundle high only, unless adequate measures are taken to ensure that the stack will remain stable. The banding straps are taut and care should be taken when cutting these to avoid personal injury and/or the bundle collapsing.
Ensure that all Keystone packaging and waste are disposed of responsibly. Due care must be given to the environmental impact of the disposal method.
COSHH- Control of Substances Hazardous to Health
Keystone lintels are fabricated from galvanised or stainless steel and pose no toxicity hazard, they are also insulated with preformed polystyrene. Most lintels contain a perforated steel key plate for rendering purposes and/or a steel strengthening plate for heavy duty requirements which also poses no hazard.
All components and materials in our products are considered as non-hazardous to health under normal conditions of use as determined by COSHH Regulations 1999.