Case Study

Overview

Thames Tower was a tired and outdated 1970’s office block which had been unoccupied for many years prior to the major extension and refurbishment works which took place in 2015/16.

Dane met with the Client’s Cost Consultants, RLB and Architects dn-a in 2014 and were invited to prepare design proposals to achieve a target rate £/m2 for the façade works. Previously, RLB and dn-a had considered a unitised façade, however upon further investigation it was realised that there was insufficient space between the defined building line and the external face of the existing concrete frame to accommodate this. We therefore came up with a solution to use an SFS strong-back trussed spandrel frame connected between the existing concrete columns, that would support the Schuco AWS70.HI windows and terracotta rainscreen cladding.

The original building had chamfered floor plates in each of it’s four corners which were extended outwards to provide a uniform 90 degree intersection between elevations. In addition, four new stories have been constructed, this was achieved by reinforcing the existing concrete columns with steel plates and using composite cellular steel beams to support the new upper floor slabs. The increased height created a more elegant proportionate building making a positive contribution to the streetscape.

Dane constructed a full size mock up of the façade on site to finalise all detailing and approvals before the commencement of our procurement and fabrication activities.

Thames Tower now has 190,000 sq ft of modern, high quality, office space with retail units and a double height entrance lobby. Externally a two storey colonnade runs around the north and east facades.

Key Aspects Of Design And Construction

Façade construction accessed from standing scaffolding began at level 2 above the double height entrance colonnade with the installation of the trussed SFS strong-back spandrel frames securing to the existing concrete columns. These frames were manufactured within our metalworks factory and delivered to site complete with the cement particle boards attached. Concurrently we manufactured and installed the S.F.S./cement particle board portrait panels which form the elevation grid arrangement and create the window apertures. All Schuco frames were fabricated in our works, the upper floors utilise the FW60 + SG façade system with AWS70 inset windows and reverse glazing adapters for the glass spandrel zones, the latter being the only external glazed element within the building. Other floors have Schuco AWS70.HI windows set in reveal of the terracotta rainscreen with a bespoke extruded perimeter profile. All frames had twin inner and outer membranes, factory fitted which is Dane standard policy. Once the frames were installed, membranes bonded and glazed we achieved a weathertight environment thereby allowing progression of the internal trades.

The terracotta rainscreen system followed the same construction route as other façade materials working from bottom up, firstly installing the insulation and substructure and lastly the tiles. The finished installation exhibits a high level of uniformity demonstrating a crisp and sharp appearance to the jointing of interfacing materials.