Thor Helical retrofit brick reinforcement

Masonry repair contractors are often faced with this structural issue and many have become highly experienced in rectifying this problem using non-disruptive modern methods of retrofit brick reinforcement manufactured in the UK by Thor Helical.

Bowing walls and lateral instability usually occurs when the masonry panels, often solid walls, aren’t connected to the floor joists, ceiling joists and stair cases. Without this connection the brickwork can act freely and will move under altering structural loads, ground movement or high winds.

It is essential for the stability of the structure that the building is tied into the brickwork in order to prevent cracking or even collapse of the structure. Engineers can design and implement suitable repair solutions to overcome this problem and provide lasting and fully concealed repair systems.

A property in Central London’s Fitrovia, once the home of the famous writer George Bernard Shaw, was suffering from major lateral instability causing cracking at party wall junctions to the rear elevation of the building.

As often with this type of property it had a narrow staircase and many rooms leading off of landings at various levels where the 5 storey 13 inch solid brickwork was completely un-connected to the main structure, leaving bowing facade walls at floor joist level and outward leaning walls at 4th and 5th floor level.

With the building being a listed structure it was essential that the repair design included a fully concealed solution that would provide adequate restraint to the masonry and the Thor Helical range of lateral restraint solutions were key to the repairs schemes success.

In order to tie the rear elevation to the flank elevation bed joint reinforcement was chased into the external rear corner at 450mm centres vertically up the entire height of the building, this was then drilled into the internal skin of brickwork where it was chased into the masonry and grout fixed creating an L shape tie to resist further outward movement. Once repointed and plastered this permanent connection remained invisible to the eye.

Cracking to junctions of stud walls were apparent and the bowing was more severe at this section which was in the middle of the rear elevation, with the plaster removed on one side of the stud wall we installed additional noggins between the studs to provide extra strength and installed  lateral restraint ties at every 400mm centres the full height of the building. The ties are installed through the exterior of the brickwork and self-cut into the timber stud work. Once installed 10% of the ties were load tested achieving a minimum of 3 K/n’s pull out force. The masonry connection was made with rapid set WHO-60 grout and once brick repairs were carried out the connection was again completely concealled.

As well as lateral restraint ties into the stud walls, lateral restraint ties were installed in the same manner into the joists of the landing floors to prevent further bowing. At party wall junctions 12mm helical pinning ties were used to reconnect abutting brickwork to complete a robust and permanent solution that will resist further lateral movement of the bowing walls.