Twistfix

Bowing Wall Structurally Secured

lateral restraint of bowing flank wall

registered contractor struc

lrt in joists

bar insertion

A home owner from Farnham in Surrey was having problems with a flank wall on his privately owned semi-detached property. The wall was actually bowing outwards at mid-point because there was insufficient lateral restraint in place.  Movement to the wall had also caused various vertical cracks to external skin of brickwork.

Therefore there was a requirement to have the wall fully stabilised in order to prevent any further movement, though the home owner wanted all repairs to be concealed.  The bowing brickwork needed to be restrained and the cracking walls needed to be repaired in order to prevent them from any weather damage and stop them getting any worse.  As with the majority of projects the customer wanted a cost effective solution which would structurally solve the defects but not cost them a fortune.

An engineer from Twistfix registered contractor Structures (SE) Limited visited the site and specified that a repair system utilising a combination of stainless steel lateral restraint ties and bed joint rein­for­cem­ent was the right form of action. This would not only prevent further bowing of the flank wall but would also work to repair the cracking.

Restraint ties from Twistfix are engineered from stainless steel bars and incorporate a self-cutting drill-like end.  A clearance hole is made in the wall and then the restraint ties are installed through theses bores, driving them straight into and through a number of first floor joists before providing a resin connection at the brickwork end. See animated video.  By doing this the walls are securely tied to the flooring structure, which is itself a structural diaphragm that is reinforced and braced by floorboards. When this is complete the bonded tie end is then made good with brick dyed mortar to conceal the location of the ties.

Crack stitching bars was installed in order to tackle the problem of the cracked brickwork. In addition to repairing the cracked walls further lateral restraint was provided by tying the flank wall back into the front and rear elevations.  Long lengths of stainless steel twistfix bars are bonded into channelled-out mortar beds with a high strength WHO 60 grout. The mortar beds are then made good by repointing in a mortar to match the existing pointing.

After successful completion, the house now benefits from having a cost effective, high quality and fully concealed brickwork sta­bili­sati­on system. The overall process was extremely quick and there were no major disruptions caused throughout the installation because of minimal disturbance to the building fabric.