In the Off-Site Manufacture report in the June issue of NSS we said the columns made by APS masonry for the Royal Opera House development in London were post-tensioned. Szerelmey, who installed the columns, wish to put the record straight.

They say each stone column was temporarily clamped to a structural steel column purely for transportation and initial erection of the structural steel. Once the steel work was erected the stone columns were released and fixed in their final positions as free-standing stonework acting as load bearing masonry for the stonework up to second floor above.

The columns read as solid stone, and for loading requirements they are, but needed to be designed to clad the structural steelwork. For site programming purposes the steelwork contractor supplied his columns offsite to have stone laced over them, ‘Polo mint’ style, in the upright position. The clad steel columns were delivered to site and erected as the first part of the steel frame that then continued above.