A rough guide to the most common building stones of our islands
The most commonly found indigenous building stones of the UK are limestones, sandstones, granite and slate.
In general terms, Limestones predominate in Southern Britain and Sandstone in the North, but that’s not conclusive – Portland and York stone, for example, are both widely used throughout the UK.
Here’s the background to the big four:
Limestone
Limestone may be the most commonly used natural stone, and for good reason. Limestone encompasses every feature you could want from a natural stone; it’s durable, easy to work with and has potential to blend in with any aesthetic, just a few of the reasons why this natural stone has been used around the world as far back as 7000 BCE.
Another reason limestone is so popular is it’s versatility. Limestone has almost endless uses, and is a key ingredient in concrete, grout and mortar amongst other cements. Beyond building uses, Limestone is also used in some dyes, farming, and even as a preservative for food. The combination of Limestone’s multiple uses with it’s availability (it is common across the North of England and the South of Scotland, as well as parts of Wales) make it a readily available, reliable stone to work with.
Despite being so common, Limestone is one of the most durable and easy to maintain natural stones available. It was Limestone that was used over 4,000 years ago to build the pyramids of Egypt, a testament to not only limestone’s longevity, but also it’s wide aesthetic range to be used in some of the oldest constructions in the world, as well as still being used for modern builds today. Limestone is also a great material to be used as flooring for heavy traffic areas, and does not wear down despite consistent and heavy footfall.
On top of all the advantages listed above, Limestone is also a great conductor of heat, which means that limestone buildings will keep a cool interior, helping not only the environment but also the residents’ pockets, saving money on the energy bills. It is also highly resistant, like most natural stones, to mould and bacteria, making it ideal for uses in kitchens or bathrooms.
Granite
This igneous rock is quarried in a small number of locations in the UK. Devon, Cornwall, Gwynedd, Aberdeen and Peterhead are all home to naturally occurring sources of Granite.
A little further afield, around 8,000 tonnes of granite transported from Aswan, alongside the aforementioned 5.5 million tonnes of limestone and 500,000 tonnes of mortar were used to build the Great Pyramid at Giza.
Granite is formed by the slow crystallisation of minerals including quartz, feldspar and mica from molten materials, this provides a wide variety of colours and grain patterns. The flashes of colour within Granite provides depth and this quality is further enhanced when a full polish is applied.
The interlocking crystal structure imparts both high strength and low water absorption, necessary for a wide range of applications, which makes it ideal not only for cladding and paving but as a plinth course.
Granite is not a material as easy to manipulate as limestone, and before access to power tools carving granite was a difficult and laborious project. However, because of the immense strength and durability of the stone, it was saved for the highest priority monuments that were intended to last through the generations, and often granite was used to form the supporting pillars of ancient cathedrals and monuments.
Its high resistance and strength means today Granite is ideal for outdoor uses, as the stone is almost impervious to the wear of the elements. It has also found use in kitchens or bathrooms similar to limestone, due to it being waterproof, stain and heat resistant and easy to maintain and clean.
Although Granite isn’t as common or as easy to alter as limestone, it is widely regarded as the most resistant natural surface available, and is the go to stone when a project needs a surface that won’t wear or fade over time.
Sandstone
Sandstone often refers to stones of sedimentary origin with a granular texture and traditionally has been heavily used in the areas surrounding the quarry locations. Many of the ‘stone cities’ of Northern England gained their name due to the heavy use of sandstone in the local architecture.
Sandstone is a clastic sedimentary rock made up on various mineral particles, mainly quartz, mica and feldspar. The individual make-up of each sandstone gives a wide range of colours including whites, browns, greys and reds. The high strength properties of sandstones make them suitable for high use areas, especially paving, while its high levels of porosity give sandstone strong non-slip properties.
Like limestone, many of sandstone’s strengths lend to its variety, and from a practical point of view as well as an aesthetic one sandstone can be adapted for use on a wide range of projects.
It also requires little maintenance, and the wide array of dazzling colours you can find sandstone in are guaranteed not to fade or erode over time. Sandstone also shines when put to outside use, due to its high resistance to damp and other weather conditions.
Sandstone can often be grouped together with Limestone due to their many shared properties, such as being good heat regulators, and the abundance in which they are available. Sandstone and limestone are both reliable natural resources, which are easy to work with and adapt to suit a range of different projects.
Slate
Slate is a stone found mainly in Cornwall, North Wales, the Scottish Highlands and the Lake District and has, for centuries, been a major source of building stone. True slate is defined by the presence of a ‘slaty’ cleavage; this allows the slate to split parallel to the cleavage plane.
Slate is a fine-grained, foliated metamorphic rock that is created by the alteration of shale, ash or mudstone by regional metamorphism. It is composed mainly of clay minerals or micas but can also contain quartz, small amounts of feldspar, calcite, pyrite and hematite.
Slates typically have high strength and low water absorption making them very easy to maintain, and therefore can be used in a variety of applications including flooring, cladding and roofing.
Slate particularly shines as a roofing material due to its high resistance to the elements, specifically it’s high degree of water resistance. Slate has a water absorption index of less than 0.4%, and is the leading material used to top residential and commercial buildings alike.
Slate is also an effective insulator of electricity, as well as being heat and flame resistant, often being utilised as a desktop in laboratory settings as well as in electrical panels. Despite it’s durability and weatherproof qualities, slate is a lot easier to shape and adapt than granite, and especially in the roofing industry is the first choice to balance ease of use and durability.
