The subject buildings were substantial 1950s style traditionally built four storey blocks of flats, stepped to accommodate a sloping site.
• Visible cracking movement was noted to the front and rear elevations of each building comprising 225mm thick solid brickwork.
• The smaller of the two buildings was constructed with a central step. Cracking in line with the step was noted to the external brickwork, to the rear and to a lesser degree to the front elevations.
• The larger of the two buildings was constructed with two steps. Cracking in line with the steps was noted to the external brickwork to the rear and to a lesser degree to the front.
The movement noted was considered attributable to seasonal moisture and the resulting thermal expansion and contraction (i.e. hygrothermal) – a predictable defect, as this large area of brickwork had been constructed without the benefit of any expansion joints.
AWT completed a remedial scheme providing a viable repair through the introduction of expansion joints.
1. Flexible joints installed: We introduced crack inducement joints. With a twin diamond bladed saw, we cut a 10mm wide joint, 110mm deep, into the external brickwork between each window and thereafter installed a flexible joint – as indicated with red lines on our proposal images – all in accordance with AWT’s methods.
2. Making good: To the crack line schedule for new joints, we raked out the existing cracked mortar and repaired with new coloured sand and cement mortar to approximately 20mm in depth. AWT operatives are highly skilled in traditional building methods and always attempt to match replacement bricks, pointing styles and mortar colour to be sympathetic with the existing building.