Bowing and Cracking Walls Hertfordshire
Newman’s were asked to carry out a survey to a Victorian end terrace property in Bishops Stortford, Hertfordshire, by a private landlord who was extremely concerned by bowing and cracking walls in this 1830’s Victorian built cottage.
Upon inspection of the property the bowing was found to be significant and that existing lateral restraint ties installed in the 1950’s had failed due to corrosion. There was cracking at the junction of the party wall with the main structure, combined with gaps appearing at ceiling level and at first floor level.
Cracking to the front of the property was also evident and the cause of this which was lintel failure, a common defect to properties of this age and construction.
The solutions to the defects was to install masonry beams drilled 1000mm and resin fixed into the party wall all the way around the gable wall and resin fixed into the rear wall a further 1000mm. This would tie the midriff of the property together and distribute the structural loads across the worst areas of bowing to sound masonry. The lintel was repaired using 450mm 9mm stainless steel Twistfix pinning ties with each bed joint within the lintel raked out and grout injected stabilising the lintel.
The joists were inspected and found to be sound with no signs of defect so 15 no 1.5m long Twistfix lateral restraint ties would be the effective solution to provide a permanent restraint to the front and gable elevations.
The party wall was tied to the external front wall with 2m long crack stitches chased from the party wall and drilled through the external front wall providing an L shaped grouted tie. The ground floor party wall was tied using 1m long 9mm grout ties. Once the grout had set pull out tests were carried out to the grout ties and the lowest pull out reading was 2.5 kn’s.
With all areas re-pointed and plastering carried out the repairs provide an almost invisible repair solution alleviating the need for costly remove and rebuild techniques and provide a permanent solutions covered by a 10 year insurance backed guarantee.