There were a lot of different proposals considered for the development of Montrose Place in London’s fashionable Belgravia before planning permission was finally given for the residential development that has now taken place. Using load-bearing St Maximim French limestone on a low plinth of Karin Grey Scandinavian granite installed by London stone specialists Szerelmey, the building houses four- and five-bedroomed apartments with courtyards and gardens enclosed behind a Welsh slate perimeter wall created by the artist Andrew Goldsworthy.
Providing 4,000m2 of new residential accommodation for the wealthy inhabitants of London’s Belgravia requires some thought, which Hamilton Architects certainly gave their development at Montrose Place between 1996, when proposals were first discussed, and 2006 when contractors moved on to site.
Ian Orr, the architect from the practice working on the development, says it went through various permutations. “It took many years to get planning permission on that site and we looked at more options than you would believe,” he told NSS, although as far as Hamilton Architects were concerned it was always going to use stone. “It had the quality that warranted stone,” says Ian.
The site spans two mews. There is an imposing oak entrance gate in an Andy Goldsworthy civic art perimeter wall from the Montrose Place entrance, opening on to a courtyard and a colonnade linking to the internal circulation cores around a ‘floating’ garden with a reflective pool. Access at the other side is through a smaller, metal gate.
The initial analysis of the site stated it was “a great location but a terrible site”. It was an awkward shape with poor access, as Szerelmey can confirm as the specialist stone contractors on the project. Contracts Director Darren Moore says: “Getting the stone in was like threading it through the eye of a needle.”
With such a valuable piece of land, some time was spent considering high density accommodation, but this was rejected in favour of larger units with gardens either side of the building. Although even these units have not proved large enough for some and the 18 original apartments are now 15, with some purchasers having bought more than one and joined them together.
Szerelmey came on board at an early stage in the project, offering their expertise as consultants on the stone. Many different kinds of stone were considered before St Maximim limestone from France, supplied by Rocamat, was finally selected.
“We didn’t want to use Portland because of the new building’s location and presence on the street,” says Ian Orr. “There’s a lot of Portland and stucco in that area and we thought this building would be better in a warmer, less stark stone. We felt the colour and texture of the St Maximim were better in this location.”
The stone was divided into two distinct versions for the project, one shelly and one plainer.
The architect wanted different stones to differentiate between the main building line, for which what was described as ‘Fine bed’ was used, and screen walls and pillars in the shellier stone that was described as “Construction bed”.
In fact, the stone does not come from distinct beds in the quarry but blocks contain both shelly and less shelly areas. It was up to Szerelmey and Rocamat as their suppliers to ensure that the individual stones used on the project were appropriately separated.
The process began in the quarry, with the quarry manager drawing on the block which areas were shelly and which were plain. The final selection for each was made after sawing. Darren Moore says to some extent it was subjective.
“We did big mock-ups at the factory and determined what the limits of the different stones would be. We went back and forth quite a lot – we were there every two weeks throughout production. Rocamat said half way through the job that they don’t usually supply so much Fine stone and they wouldn’t do it again because there was a lot more waste than they had thought there would be.”
A third French limestone, Lens, a clean white stone, has been used as balcony features and there is a Karin Grey Scandinavian granite sock around the bottom of the walls.
Darren says the project used 2,500m2 of stone. The ‘Fine’ was 75mm cladding and the ‘Construction’ generally 100mm. There is 500tonnes of finished stone in the construction appearing as more than 17,000 individual elements.
There is a look of randomness about the stone but in fact it is a 1.5m modular design that everything adheres to. There are five different course heights, from 125mm to 625mm. The detailed design, including fixings, was worked out between the architects, Szerelmey’s own in-house designers and consultants Harrison Goldman and Stewart Design.
Because the floors are formed by post-tensioned in situ concrete slabs, Szerelmey had to be careful where they drilled to fix the stone, which meant some thought had to be given to the design of the fixings.
The architects were keen to avoid horizontal expansion joints, so the stone is self-supporting. It is tied back to the structure for restraint purposes, but the load goes down through the stone. The central columns and quoins are generally solid stone because the aesthetics were more important than the cost and the desire was for a monolithic structure.
Some sizeable lintels were required, which are precast concrete with a 50mm stone facing made by Thorpe Precast in Newcastle-under-Lyme.
A lintel to support the stone would have needed a compression joint above and below the lintel, which the precast lintels did not require as they are part of the self-supporting walls.
The architects originally specified 3mm joints. “We discussed it at length,” says Darren Moore. The specification finally agreed allowed for a tolerance of ±1.5mm around 3mm, which still called for accurate sawing by Rocamat and attention to detail on site by Szerelmey. During the 15-month project Szerelmey had up to 25 people on site at a time.
At the end of the project, the architect is full of praise for the work Szerelmey have carried out, especially their design contribution to achieving a random look to the stone in spite of the precise design of every piece.
“We’re hugely happy with it,” Ian Orr says. “It’s a great project.”
Szerelmey are also delighted with it. “I think this is a magnificent building,” says Darren.
But the stonework does not finish on the outside. Stone has also been used for interiors. This work was carried out by Marmi, in Maldon, Essex.
In the public areas, including reception and the floor of the colonnade, and on the balcony floors of apartments they have laid travertine. There are 340m2 of it in the external colonnade and 660m2 of paving on the balconies. And they have fitted the stone in the bathrooms of the original 18 apartments. Each apartment has four or five bedrooms and all of them have ensuite bathrooms.
The stones used, imported by Chris Higgs of Marmi, include Crema Marfil, Azul Valverte, Rosso Levanto and dark brown Emperador vanity tops with sinks made from the same stones fixed into them. There are mosaic panels on the walls and some Carrara Bianco and Statuary.
“Every bathroom was different,” says Chris, “and every joint had to line up with something – like the centre of a tap. We had to reject quite a lot of material to get what we used all uniform.”
Marmi also produced a slate water feature just inside the main entrance. It provides a continuity of theme from the Andy Goldsworthy Welsh slate sculpture perimeter wall.
The wall has attracted a lot of admiring interest, as Andy Goldsworthy’s work often does. The artist can pick and choose his projects and, says Ian Orr, “fortunately he picked and chose this one”.