The subject building was a traditionally built mid-terraced domestic Victorian/Edwardian house in South London on two floors below a pitched tiled roof.
Bowing brickwork piers and cracking, dropping and sagging of the structure around the bay window required urgent attention. Using equipment and methods designed by Action Wall Ties, the bay window was reinforced and repaired.
Action Wall Ties’ investigation reported distortion and distress with localised cracking to ground floor, external spandrel brickwork and cracking and dropped key stones to the brick arches.
The slender brickwork columns to the ground floor had bowed outwards leaving a bow shaped space between the timber box window frame and the brickwork column that has been repeatedly re-pointed.
The bay window has a very large overhanging cill with supporting corbelled knees.
Action Wall Ties reported that the movement noted was considered to be progressive due to a combination of ageing and ineffective restraining of the slender brickwork columns and rotational effect of the overhanging cills, causing the bowing out of the columns and the arches to spread, crack and drop – cracking the supported spandrel brickwork above.
Our remedial scheme involved the introduction of bed joint reinforcement beaming, lateral restraints, reinforcement to the brickwork columns and grout tie injections, together with concrete repairs to masonry cill, all to reinstate the uniformity of the wall and provide restraint.
We provided temporary support to the underside of the ground floor brick arch key stones, removed the debris from the cracks and lifted the stones/arch back into a more level line with the adjacent brickwork.
As indicated with red double dotted lines on our proposal 1, we introduced two rows of twin stainless steel corded joint reinforcement, forming a deep masonry composite beam.
As indicated with green parallel lines on our proposal 1, the beam reconnected the bay window elevational brickwork, and this was accomplished with AWT designed equipment enabling us to diamond drill through each elevation and chase into the main elevational brickwork and install a grouted helical bar.
The formation of continuous beams within the existing masonry should redistribute the upper storey loads, to a large extent, to those parts of the supporting structure, below which are best able to carry them while at the same time assisting in restraining diagonal cracking and bulging tendencies.
As indicated with yellow stars on our proposal 1, in conjunction with the beams, we drilled for, and screwed direct into the timber floor joists, 8mm stainless steel lateral restraints – all resin bonded to the masonry.
As indicated with green parallel lines on our proposal 1, to assist in alleviating the rotation affect from the large cills we installed grout ties vertically, drilling for and injecting a grouted 8mm helical bar.
As indicated with blue parallel lines on our proposal 1, we introduced a purpose fabricated steel reinforcing post, fitted and fixed to the inside of the brickwork columns, fixed with stainless steel resin bonded fixings.