88 Goswell Road is a five-storey, plus basement, terraced commercial building in Clerkenwell. It recently underwent a refurbishment to provide modern and flexible office space, with Anomaly as Architect.
The building is loadbearing masonry construction with concrete filler joist floors spanning to primary steel beams, which in turn span from party wall to party wall. Over the years the building had been cut and carved and so part of our work involved demolishing the previous extensions and inserting a new steel frame to create a full width opening while supporting extra office space and a roof terrace.
We needed to figure out a way in which to support the existing masonry and filler joist floors while removing the existing frame and inserting the new, wider, steel frame. A typical approach to this scenario would be the installation of needle beams (temporary beams) and propping these down to the ground floor or temporary footings. Filler joist floors aren’t designed to support heavy point loads so we couldn’t prop directly off the floors at Goswell Road, and as we were at level 3 of this narrow, working site, back propping all the way through to the basement wasn’t practical, so we needed an alternative option.
Associate Sam Rogers proposed scissor needling as the solution. For anyone unfamiliar with the process, holes were punched through the top and bottom of one of the existing walls at level 3, and needle beams were inserted and packed out. At this point an adjustable prop and tie rod were inserted to support the needles. The existing wall was then demolished which left the temporary prop, tie rod and needle beams to take the weight of everything above. A steel portal frame was then inserted to provide stability and create the new wider opening. The temporary needles were then removed and the holes in the brickwork were then packed out and made good.
An added bonus of adopting scissor needling allowed us to work from one side of the wall only, opening up the amount of useable space as a working site and giving the contractor greater flexibility as to when to bring and store materials on site.