Fixing Cracking Above Concrete Boot Lintels
Concrete boot lintels to window openings were in common use in the 1970s and have the unique appearance of a visible one course high concrete toe that appears not to have any bearing onto the adjacent brickwork (i.e. the visible concrete toe is in between the brickwork reveals).
Concrete Boot Lintel Problems
This type of lintel has no bearing onto the external brickwork and is reliant on the bearing onto the internal skin. The internal skin bearing the lintel should be of a material capable of withstanding and spreading the load (e.g. concrete blocks or engineering bricks)
In many cases the lintel was bedded directly onto lightweight blocks that are unable to take the imposed load and compress the outer edge of the bearing, rotating the lintel and allowing the external brickwork above to crack and drop as described in BRE Good Building Guide 1.
In the 1960s and 1970s, many concrete boot lintels were incorrectly fitted onto unsuitable bearing causing the lintel to rotate the supported brickwork to drop and crack.
Concrete Boot Lintel Repairs
Action Wall Ties provide a cost effective, long term solution that retains the existing appearance of the brickwork with the minimum disruption to the occupants and the environment.
Action Wall Ties have developed a remedial system and methods (included specifically designed equipment) to remedy the problem of cracked concrete boot lintels. Action wall ties slightly anti-rotate the lintels back in place, drilling for and resin bonding 16mm stainless steel shear pins to both end bearings, once set releasing the props pre-loading the shear pins thus reducing any further cracking.
To wider lintels scheduled for treatment it may be necessary to introduce two rows of twin cord reinforcement, forming a composite deep masonry beam. To the underside of the concrete toe we drill for and inject grouted 8mm helical stainless steel pins passing into the line of the deep masonry beam to arrest any further rotation of the concrete lintel.
Action Wall Ties concrete boot lintel repair and replacement solutions are available to clients in London and the South East.
Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, lintel repairs, replacing a damaged lintels, and providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.