The unusual geology of Purbeck in Dorset produces a variety of attractively distinctive stones that Lovell Purbeck are using to diversify the range of products they make from the limestone.

Anyone who has seen just one building with Purbeck limestone walls or a floor of just one bed of Purbeck paving could be forgiven for believing Purbeck is a buff colour, or dark blue, full of fossils or relatively free of them.

Purbeck is all of that… and more. Because the stone extracted from Purbeck in Dorset was laid down on the bottom of an isolated shallow lagoon at the end of the Cretaceous and throughout the Jurassic in around 200 distinct beds.

The different beds represent different life forms dominating the lagoon at various times. They might have lasted a few million years each, with the calcium carbonate of their skeletons building up on the bottom of the lagoon to create one of the beds before another lifeform evolved to dominate and create another bed.

Eight of the beds form recognised building stones – Burr, Thornback, Whetson, Grub, Roach, Freestone, New Vein, Royal Blue. There is also Purbeck Marble, which is encountered among the other beds from time to time.

All of the recognised beds (as well as the unrecognised beds) are found in the quarries of Lovell Purbeck, the company created when operation of the three quarries (Downs, South Downs and Acton) worked by D&P Lovell at Langton Matravers near Swanage, Dorset, was taken over in 2009 by the Hart family, based in Somerset. The Harts created the successful Royal Forest Pennant paving brand made from Forest of Dean Pennant sandstone and now own a third of the company that supplies their Pennant, Forest of Dean Stone Firms.

Lovell Purbeck is run by Simon Hart and his brother James. Earlier this year they also bought the Lias limestone Bowdens Quarry in Somerset from Ham & Doulting Stone.

Bowdens Quarry is believed to have the only consented reserve of White Lias limestone in the UK, as well as significant reserves of Blue and Grey Lias. Developments are taking place there that will be featured in a future edition of NSS when they have been completed.

On Purbeck (it is technically an island, although most people driving there would be unaware of the fact), some of the beds are not suitable for building stone, but some have not been used traditionally simply because they are too hard. With modern processing machinery that is less of a problem than it has been historically and Lovell Purbeck hope to bring more of the beds into production – in fact, they have already done so for roof tiles, which traditionally come from Downs Vein. Lovell Purbeck are using the flame texturing machine that is just a part of the investment they have put into the operation to make roofing tiles using a different bed. When they are flame textured they are indistinguishable from Downs Vein tiles and are produced in the same diminishing courses, from 34-36inches (900mm) down.

Because there are so many different beds of Purbeck, the size of blocks extracted is limited,. The smallest are used for walling and the larger are sawn for paving / flooring.

The largest volume of stone from Lovell Purbeck is sold as walling for housebuilding – even now, when housebuilding is at a historically low level, they are producing 600m2 (125tonnes) of walling a week. (There is a pictures of Purbeck houses in the housing report that starts on page 26).

Purbeck is sometimes used as paving, but Lovell Purbeck would much rather sell it as value-added flooring. To that end they have just installed a 70m long Donatoni tile line in their factory. They believe they will be able to produce 100m2 of calibrated, chamfered tiles a day in a polished, honed or brushed (antique) finish.

That might be more than the level of demand for Purbeck could sustain, but they are not only processing Purbeck. They will also be making tiles in their own Lias and other English limestones, such as Portland and Ancaster, that they will buy in to keep the Donatoni line working.

That will also increase production rates because some of the Purbeck beds are harder than a lot of granites, whereas other limestones are not so hard.

The tiles are being sold to specialist retailers for the expanding sector of the domestic market that is prepared to pay a bit extra for indigenous stone, with all the aesthetic and environmental advantages that offers.

However, the biggest part of the market remains specification driven and a significant sector of that is the ecclesiastical market.

There are many examples of beautiful Purbeck floors available for the public to see in cathedrals and churches all over the country. The new floor supplied by Lovell Purbeck for St John’s Church in Hyde Park, London, was pictured in the previous (October) issue of Natural Stone Specialist and another, at St Mary’s Church on Hayling Island near Havant in Hampshire, is pictured at the top of the previous page.

One of the advantages of using a local stone is its low encapsulated carbon content, which Lovell Purbeck are reducing still further by having photovoltaic cells installed on their roofs. They are not using all their roof space because of the Government’s restriction, imposed in August, on the top rate of feed-in tariff to units of less than 50kW.

The restriction means the PV cells can supply about 20% of Lovell Purbeck’s electricity requirements. The cells should require minimum maintenance and are expected to have paid for themselves in 8-10 years.

Another area of investment by the new owners has been in water management. With the extra saws and the tile line that Lovell Purbeck have added to their operation the factory can need as much as 1,000L of water a minute. To accommodate that they are capturing rainwater from their roofs and have installed a big water recycling unit with a filter press.

With all the new machinery has come extra jobs – now 30, up from the 25 that Lovell Purbeck inherited – including their first apprentice, Jason Saunders, who is attending Weymouth College.

Simon Hart is pleased with developments at Purbeck so far. He told NSS: “We are developing new products all the time at the moment and sales are increasing month on month, although we’re an embryo business and have spent quite a bit of money putting in new equipment and on marketing the products.

“Purbeck… yes, it is expensive but it is exquisite and will last practically for ever – what’s better value than that?”