Underpinning of an exisiting load bearing party wall constructed using Maltese local limestone blocks also known as Globigerina limestone or in Maltese, Gebel tal-Franka. Works were required to enable the general excavation of the site whose bottom level was lower than that of the adjacent site. The loadbearing walls of the neighbouring property were placed directly on a levelling concrete blinding layer without any foundation.
Works consited of of drilling a steel U-channel with bolts to the existing limestone blocks, excavating 1m pockets, fixing steel reinforcement, erecting formwork and casting concrete on the same day. Pockets were opened in a sequence until all pockets in rock where opened and a continuous cast in situ, reinforced concrete wall was built to underpin the existing wall. Sequencing of works was required to allow the concrete to achieve the required target compressive strenght and thus prevent damage to the third party wall.