Stones used for buildings in London
What’s my house made of?
When I’m asked to look at Victorian terraced houses it’s usually been after several other tradesmen have given their opinion. Common misconceptions are that the material behind your painted bay window is either sandstone, stucco, concrete or precast stone. Whilst none of these are inconceivable, the likelihood (95% of the time) is that the features are made from a type of Bath stone. Bath stone, despite its sandy texture and appearance is not a sandstone, but an oolitic limestone (comprised of fossilised oolites) which originates in and around Bath in The West of England (now Northeast Somerset). It’s been quarried and mined for millennia, and is the stone that built the eponymous city (a World Heritage Site) from Roman times through to Georgian and present day.
An example of Bath Stone
Why not use London Stone?
Why use a stone from 120 miles away for buildings in London? Well, there is no indigenous London stone, and when London swelled up with its population surge in the 19th century houses needed to be built and fast, and the softer Bath stone made it quicker to work and therefore made bigger profit for the developers. However, please do not think its softer structure means it weathers badly. A lot of much harder stones do not survive out in the open as long as Bath Stone.
It can be used for rubble walling, fine detail and sculpture.
Limestone Carving of a wyvern (legendary winged creature) by Geraint Davies
Other materials used
Much of the City of London – the more prestigious buildings – was built from Portland Stone, originating from Portland Bill in Dorset. Portland is a dense limestone of whitish grey appearance and was formed around 150 million years ago. A few Portland stone buildings of prominence in London are: St Paul’s Cathedral, The Bank of England, Buckingham Palace (the facade ) and The Royal Courts of Justice.
While Portland is an excellent building stone and superb for fine carving and sculpture, it does take around 30-50% longer to work than Bath Stone, and is more costly when bought by the cubic meter. The one ton block of basebed I used for the Christ sculpture below cost £1,500.
Statue of Transfigured Christ in Portland stone, carved by Geraint Davies
Other stones, some rarer and some no longer available: Weldon, Ketton, St Bees sandstone, Anston from Yorkshire (which has been the bane of The Palace of Westminster) and Clipsham from Lincolnshire. Kentish ragstone is very common but cannot be worked or carved dues to its irregular nature, provides rubble walling on many London churches.
Often a decision has to be made when replacing a stone which is no longer quarried and Bath Stone is often the answer, although in the case of Parliament it was Clipsham. I have worked on an unnamed cathedral where English Heritage insisted on using the remaining stone from the original, surprisingly small quarry. Because the good stone had been taken out the only available material was extremely poor quality (being mostly blue calcium and very granular) and it started to degrade within only a few years.
Foreign invaders
William the Conqueror brought over Caen stone from Normandy to make his famous White Tower which became the Tower of London. However, Caen stone does not weather well and the Tower has been re-faced. Nevertheless, when Queen Victoria made Buckingham Palace her official London residence it was used for the original facade of the facing side to the Mall. However, only 20 years had passed before it started disintegrating in London’s polluted air (and raining down on the heads of guardsmen!) and a decision was made to replace it in 1913 in Portland.
So please ask when you have some eroded features on your house and you don’t know what they’re made of as I may have a better idea than most. Please call me on 07803908066 or email me at geraint@geraintdavies.co.uk
For further reading: Building Stones of London – British Geological Survey