Walsingham House – located near Fenchurch Street Station – will have its interior structure demolished and new piled foundations installed to enable the construction of two additional floors.
The transformation will create nearly 50% more office space, bringing the property’s net internal area to 65,000 sq ft.
Matt Blowers, managing director of UK Fit Out and UK Construction South at ISG, said: “As prime office locations continue to attract high rental yields, property owners are increasingly looking at all options to increase capacity and provide modern layouts to maximise portfolio yields.
“Managing complex interfaces and operating in logistically challenging and busy environments is where ISG really excels as a business and this latest scheme further strengthens our credentials as London’s leading office contractor.”
The project will begin with enabling works and an archaeological investigation, which is expected to include sections of Roman road and structural elements from the 13th, 16th and 17th centuries.
Walsingham House’s original Portland stone façade will be cleaned and restored, while the two additional floors will also feature matching contemporary stone cladding.
London-based ISG currently employs over 2,800 employees across 28 countries, including Germany, Russia and Japan.