When the construction industry wants to know more about the stone it is using it often turns to London-based consulting engineers Sandberg – as it has done for 150 years

There is a distinct gravitas to Sandberg’s offices in Grosvenor Gardens – or 'the new offices', as Neil Sandberg, the Managing Partner, likes to call them, as only someone steeped in the traditions of the family business could. They have been the ‘new offices’ since the consulting engineers moved into them in 1919. By then, the business was already almost 60 years old.

The offices contain the memorabilia of the 150 years in business that the firm celebrated last year. Neil Sandberg, great-grandson of the founder, Christer Peter Sandberg, who came to England in 1860 as an engineer for the Swedish State Railways, recounts the stories behind the artefacts.

On the boardroom wall are two paintings by the famous artist Stanhope A Forbes. They show the tramway being built on the Embankment. They were painted from the balcony of the Savoy after the partners had taken the artist to dinner there. He has taken some artistic liberties with the topography of London, moving St Paul’s and Cleopatra’s Needle so that they can be included in the pictures.

There are bank notes and other artefacts salvaged from the wreck of SS Egypt in 1935, one of the most famous salvages ever because the ship had been carrying 10tons of silver and 5tons of gold bars, as well as a large amount of sovereigns and bank notes when she sank in 1922 in more than 400feet of water in the Atlantic. At that time, no diver had ever been to that depth and it took the skills of Sandberg to make it possible to recover the bullion.

There are sections of steel railway track that do not, on the face of it, look so impressive, but mark the contribution made by Sandberg to the development of railways, including a rail that could withstand heat expansion and contraction. Before its use was made mandatory in the USA in 1929, there had been 11,000 sections of track replaced each year. Afterwards the number fell to just seven.

Sandberg were involved in railways across the world – one of the locomotives they designed that went to China can now be seen in the National Railway Museum at York – and other great engineering feats, including the construction of the Forth Road Bridge in the early 1960s, for which they set up a laboratory on site to test the 39,000tonnes of steel that went into its construction. Sandberg still do a lot with steel but their activities have expanded to offer consultancy and testing services across all construction materials.

Sandberg have a fascinating history and can be forgiven for indulging in nostalgia while celebrating their 150th anniversary, but today are looking forward rather than back.

Over the years, their guiding entrepreneurial spirit has enabled them to see when markets have reached maturity and to identify new areas to move into. It is why they now have diverse areas of interest, one of which is the geology department run by Partner David Ellis, who was elected as the new President of Stone Federation Great Britain at the Federation’s AGM in November.

David’s team of eight geologists form only a small part of Sandberg’s operation but it is a part that is still growing, aided by the acquisition two years ago of Mike Eden’s company, Geomaterials Research Services.

Mike and the people who worked with him moved with their laboratory from Basildon into Sandberg’s laboratories in Carpenters Place, Clapham, which is where the geologists spend most of their time, rather than in the head offices. The buildings in Carpenter’s Place not only house the geology, chemistry and construction materials laboratories, but also the building inspection and investigation department and the equipment the consultants take out on site with them – such as ground penetrating radar (GPR). And it is not only used in the UK. Sandberg’s reputation still takes them all round the world – two years ago they were even looking at opening an office in Shanghai.

The Geomaterials acquisition not only brought the expertise of more geologists into Sandberg, it also added a £150,000-or-so scanning electron microscope (SEM).

“I still think of it as mine,” says Mike Eden, who was overjoyed to find someone to take over his business so he could return to the lab full time, especially as Sandberg were willing to invest in the upgrade to the Inca operating system he wanted for the SEM.

Having an SEM makes a significant contribution to Sandberg’s in-house UKAS accredited testing and analysis capability – and the fact that they have such a range of facilities and expertise in-house has always been one of their strengths. The SEM is invaluable for investigating staining of stone, for example, by providing quantitative information about the chemicals involved, which can be important in insurance claims.

Even their history is of more than academic relevance to their clients today. It gives Sandberg an enormous library of reference materials and a vast amount of knowledge across the whole spectrum of building materials.

Sandberg have not taken over many businesses, but Geomaterials provided a solution when they were finding it difficult to recruit the skills they needed for the expanding workload of the geology department. Neil Sandberg explains what attracted them to Mike Eden’s company: “Excellence. It’s almost too strong a word but that’s what I’m going to call it and that’s what Geomaterials had. It was bringing together two businesses with very similar philosophies.”

Such is the respect Sandberg are held in by the industry that they will often be working for the developer, the main contractor and the specialist contractor at the same time on a project.

David Ellis says: “It makes sense to have a single point of consultancy and testing – as long as they all understand the information is open to the whole project team. Of course, if it’s confidential we will represent a single party. But normally if we work for them all, they accept us as the experts and what we say goes.”

Lately, with the worsening of the economy, Sandberg have seen an increase in their workload as expert witnesses in disputes. Both sides then engage their own experts. Stone is well understood by geologists, so the arguments in such cases are not about the nature of the material but the subtleties of its use. “It usually comes down to something like inadequate movement accommodation and / or the related workmanship,” says David.

Another part of the stone side of the business that is busy is the testing of indigenous stone as quarry operators have generally accepted they need to CE mark their stones to show they are fit for the purposes for which they are being sold.

Take BSEN 1341 for external paving. It calls for flexural testing, followed by 48 freeze-thaw cycles and then another flexural strength test. To pass, the stone strength reduction must be less than 20%.

David says CE Marking is still a moving target in many cases but European standards are being referenced increasingly and suppliers of both indigenous and imported stone realise they need to be able to offer accredited test results.

Architects (or the engineers they are working with) are also always looking for novel solutions to the questions their designs pose, which often involves testing stone in relation to fixings and the thicknesses required for the sizes of panels specified.

The stone market is just one of the areas that Sandberg see as offering them potential for growth in the years ahead, because although they can look back on a distinguished history of materials consultancy, they prefer to look forward to a distinguished future in the field.