Bowed Flank Wall on Victorian Semi

Victorian semi-detached house with very large bowed flank wall. AWT used bed joint reinforcement, lateral restraints and resin bonded ties to realign and stabilise the bowing brickwork. As with many properties that AWT is called in to repair, the property showed signs of previous repairs that had failed to address the underlying structural issues.

case study 56e199919bebb7.47063350 - Bowed Flank Wall on Victorian Semi


The Structural Problem: Bowing Flank Wall

This substantial Victorian traditionally built semi-detached house is a domestic residence spread over three floors. As shown in the photo, the flank wall had a significant visible bulge in the centre of the wall at first-floor level. No significant cracking was noted. The third floor (top level) appeared to have been rebuilt.

The AWT survey team judged the movement of the masonry to be progressive and in need of stabilisation to avoid the entire wall collapsing. The previous rebuilding of the third floor brickwork failed to tackle the weakness in the structure that was allowing the brickwork to bow outwards.

What Causes Bowed Brickwork?

As is common with Victorian properties, the bowing masonry was due to some downward movement compounded by ineffective or inadequate restraining. Under the weight of the masonry above, and without strong enough fixings to tie it to the main body of the property, the brickwork bulges outwards.

debonded brickwork bulges 1.3 - Bowed Flank Wall on Victorian SemiThe bulge may have been formed by some de-bonding of the brickwork (or cracking of the headers). It was common practice in buildings of this age for a 9-inch wall to be constructed as two half-brick walls with snapped headers to the external skin to save on expensive facing bricks. This results in a less structurally stable wall, compared to fully bonded brickwork, because the inner and outer skins of the wall are only connected by mortar.

The Structural Repair Solution

AWT’s remedial scheme involved the introduction of bed joint reinforcement, lateral restraints and resin bonded ties (see coloured remedial works on our proposal picture.) This added tensile strength and reinstated the brickwork’s integrity and the uniformity of the wall. After installation, the pointing was raked out, reinstated and tinted to match the existing.

case 1 a - Bowed Flank Wall on Victorian Semi

1. Bed Joint Reinforcement:
The AWT team installed two rows of twin cord reinforcement, forming a deep masonry beam – indicated by red double dotted lines in the image.

2. Lateral Restraints:
In conjunction with the beam, 8mm stainless steel lateral restraints were introduced and screwed directly into timber floor joists’ end grain or into the side grain and resin bonded to the masonry – indicated with yellow stars in the image.

3. Wall Ties to De-bonding Brickwork:
Using specialist precision drilling rigs, the AWT team drilled for and installed new resin bonded, 6mm stainless steel remedial ties – indicated with blue lines in the image. Disturbed areas were re-pointed with colour matched sand and cement mixture.

Cost Effective Structural Repairs

Rebuilding work would have been, slow, messy and expensive. The affected rooms would also have been uninhabitable during the rebuilding work.

AWT was able to provide a long lasting structural repair that got to the root cause of the bulging brickwork. The bowing masonry was strengthened and brought back into vertical alignment. No visible fixings or rebuilding work was required. The vast majority of the work was carried out from the exterior of the property thus minimising the disturbance to the residents and to interior finishes.

Action Wall Ties (AWT) based in Canterbury, Kent, are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems in London and Kent. Contact us on 01227 721 255, or email us.


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