The picture on the Natural Stone Specialist cover this month shows the Fletcher Bank sandstone of the new science building at the independent St Paul’s School in London.

The stonework by London-based specialist contractor Putney & Wood to the design of Nicholas Hare Architects has already received considerable recognition.

It has been Highly Commended in the Natural Stone Awards presented on 5 December at Russell Hotel in London. It won a Civic Trust Award this year and was shortlisted for Project of the Year at the 2014 Education Estates Award presented in Manchester in November.

It was also shortlisted for a New London Award and a RIBA London Award and it was Highly Commended at the 2014 RICS London Awards for its Design Through Innovation.

And Lee Hutchinson, Project Director for Mace, the main contractor on the project, has just been crowned Construction Manager of the Year.

He was selected overall champion out of 11 Gold Medal winners in categories ranging from small residential projects to schemes worth more than £100million.

Congratulating Lee, Putney & Wood said: “He was a pleasure to work with on the St Paul’s School science building project last year and we look forward to working with him on the next project.”

The science building, the first new building to be erected at the school for 50 years, was handed over in January last year, completed on time and under budget.

The Fletcher Bank sandstone used is handset with support fixings and compression joints at evey slab level. It is 75mm thick for most of the building, although it is 100mm thick on a feature wall to allow it to be carved at some future date. It was supplied by Marshalls Stancliffe Stone from its Fletcher Bank Quarry in Lancashire.

Fletcher Bank is a distinctive fine to medium grained buff to grey sandstone from the Millstone Grit series of Carboniferous age and is particularly striking when used for large scale cladding projects like this, harmonising with existing urban surroundings.

Nicholas Hare Architects was appointed in 2006 to develop a masterplan for St Paul’s School that would see the replacement of the school’s 1960s prefabricated CLASP system buildings with new, high quality, BREEAM ‘Excellent’ rated structures. The new science centre was the first of these new buildings.

The four-storey structure creates a new courtyard and entrance to the school and provides 18 state-of-the-art schoolroom laboratories.

The Fletcher Bank stone handset by Putney & Wood complements buff coloured brickwork. Lime mortar has been used to avoid having to incorporate expansion joints in the stone or brick.

The mass of the masonry, with 450mm deep window reveals, juxtaposes with large areas of glazing, bronze anodised aluminium windows and rainscreen cladding.

The glazing maximises daylight while the deep window reveals and solar shading louvres minimise solar gains. The thermal mass of the structure also helps to regulate internal temperatures.

A bespoke, biodiverse brown roof provides habitats for creatures and moderates rainwater run-off to contribute to the sustainable drainage strategy. Biomass boilers will be added to the school in the next phase of building work, which will see the addition of a new drama centre.

Nick Booroff, P&W’s Project Manager, told NSS: “This was an interesting project to work on. The design is eye-catching and shows off the stone to great effect. The architect created interesting features and details, which give the building a unique character. It meant our design team had to overcome a few challenges, which they rose to.

“The architect made a good choice in Fletcher Bank. It’s always nice to work with an English stone, but it’s quite rare to use sandstone on a building of this type in London.

“Fletcher Bank is a good quality stone with some lovely tones that give it a warm character. It works extremely well on this job. The range was quite rigorous but all parties worked together to deliver what we think is a really good job.”