Located in one of the most prestigious areas of central London, 40 Portman Square, which is due for completion this summer, is already 70% let. This fact coming on the back of the building attracting some of this year’s top rental prices at £1,184/sq.m.

The £35 million pound new-build project has replaced the folorn, drab, 60’s edifice that once stood there bringing sharp lines of stone and glass to the south side of the square.

Comprising seven floors of modern, column-free office space and two floors of residential above in the form of 20 apartments, 40 Portman Square offers stunning views of Hyde Park, and the West end.

The building is constructed of precast Portland stone columns fixed to an independent steel frame with elements at ground floor being built in traditional handset stone on a granite plinth.

Szerelmey were responsible for the design, delivery and installation of some 273 components made up of 95 No. spandrels, some in excess of 6.00 metres long and weighing in excess of 4 tonnes fixed back to the in-situ concrete floor slab, the 112 No. Portland stone on precast concrete panels, many of which were two storeys high and weighing over 9.00 tonnes and the 34 No. brick-faced panels on the south façade. Copings at 6^th and 7^th floor levels to the entire length of the north elevation completed the precast elements.

Coordination of deliveries was particularly difficult due to the panels being manufactured in Belgium necessitating frequent visits to the factory to quality- check the castings. Panels were manufactured to tolerances of +/- 2mm.

The Chinese granite plinth to the north and south elevations is supported by a concrete toe beam below ground level, whilst the handset stone is fixed using stainless steel corbel plates at each floor level with restraints at each course. By far the most challenging area to fix with handset stone were the soffits at 2^nd, 6^th and 7^th floor levels as they required purpose-made, stainless steel soffit hangers due to the fluctuating soffit levels of the in-situ concrete floor slabs.

Internally the reception area comprises Portland stone stack-bonded walling to the right flank of the main entrance and to the immediate left a two-storey expanse of handset stone is visually pleasing.

The project was completed within budget and on programme.