Stone is an intrinsic part of the building landscape in the UK. The best known of course is limestone but granite, sandstone and slate are also key components of our Britishbuilding history. If you’re building or renovating in a stone-rich area then you’ll be required in many instances to use stone as your cladding choice, and you will be joined by many others who love the solidity, look and feel of stonework so much that they elect to use it, in whole or in part, for their own projects, regardless of location.
But the truth is that many self builders get it completely wrong by either choosing the wrong stone, getting it cut badly, or through poor laying/pointing — or, in many cases, a combination of all three.
It comes from the unavoidable problem that stone is the most expensive of all the cladding types and that those looking to cut corners almost always come unstuck. The happy news is that there are many pleasing solutions for those building in stone, giving more choice; that the ‘alternatives’ are more convincing than they used to be; and that, most importantly, if done well, stone can be the most glorious of materials.
Interestingly, there has been a redefinition of the appropriate context for stone in recent years. Long associated as a traditional building material, many of the best recent contemporary-style schemes have featured stone too — often applied in a different way (echoing dry walling techniques) but utilising the same stone. Planning authorities often feel that natural local materials such as stone can allow a contemporary structure to ‘bed’ better with its surroundings, making it easier to justify.
Stonework courses explained
(Left to right) Ragwork, Slate Walling: Rough thin stones laid horizontally, perfect for naturally thin slate; Uncoursed Ashlar: Squarely dressed stones laid in different sizes in random order; Polygonal Uncoursed: Stones dressed to have many sides, laid in an irregular pattern; Coursed Ashlar: Squarely dressed stones laid coursed, in a methodical system; Rubble Walls: Random sized and shaped stones produce a random pattern
New ‘Dry Stone’ Walling
Stone has traditionally been the go-to material for those building or extending in traditional style, but in recent years some of the finest contemporary-style new homes in the UK have re-contextualised natural stonework — to great effect. Most commonly this is in the form of, to the naked eye at least, ‘mortar-free’ dry stone courses that in fact incorporate very thin jointing with a hidden mortar — a modern update on the traditional dry stone wall.
Architect George Batterham of Batterham Matthews Design is a big fan of the use of stone in this way and used it on The Daily Telegraph Homebuilding & Renovating Award-winning home he designed in Gloucestershire: Cranham Lodge (below). This particular home uses a locally sourced limestone on a dramatic and highly contemporary curved front elevation — but the real highlight is the laying.
“They are best done by actual stone wallers who normally do field walls, as illustrated at Cranham Lodge, who focus on finding the right stone for a particular place, allowing a looser texture,” explains George. “Brick layers and stonemasons are trained to work with regular-shaped bricks and stone blocks and measure the quality of their work by how smooth and level their walls are.”
George calls the technique ‘two-thirds bedding’ which explains the key to its success. “Technically these walls consist of a facing stonework on a concrete-backing block bedded on the back two thirds only, so the stonework is not structural.
“In respect of the specification for the mortar used for the two thirds bedding, it is best to use a stone dust with white cement and lime, matching the hardness of the mortar mix with the stone used,” concludes architect George.
Britain, of course, has a very strong history of building in stone — although it was only when woodlands began to diminish in the late 1600s that stone began to be considered an option for ‘ordinary’ buildings. For many centuries until then it had been the reserve of grander structures such as castles and churches.
Stone was expensive to extract and lay and it wasn’t until the 18th century that it began to be used for simpler homes such as cottages. Of course, Britain is now famous for its building stone thanks to its happy location on top of the Jurassic belt which runs from south to north and incorporates all of the nation’s limestones and sandstones. In areas where there was no local natural stone, such as London, necessity was mother to the reinvention of clay, found in abundant quantities under the ground in the south-east, as the main building material (for bricks).
The happy news is that stone is a viable (and in some cases essential) choice in most parts of the UK. Building stone tends to be a very local affair. It was hewn from quarries and, in the days before cheap transportation, could only be carried the shortest of distances. Some of these old stone quarries survive and supply the demands of the local construction trade. In some areas there are thriving second-hand markets in stone walling materials, yet nowhere is natural stone a cheap material.
Looking for quarries and good suppliers is usually best taken on in collaboration with an experienced local stonemason. Try the Stone Federation (stonefed.org.uk) or, ideally, your local conservation or listed buildings officer for any good recommendations on stonemasons. Another good resource is the Directory of Mines and Quarries, available as a free download from Minerals UK (bgs.ac.uk/mineralsuk).
The cost of laying stone varies a little depending on its characteristics and whether it’s coursed or not, but a good stonemason would hope to lay around 3m² a day, so the laying costs alone are likely to be more than the cost of most other cladding systems. That makes the typical stonemasonry costs on a stone-heavy home easily into the £10,000s. Most new stone walling is now laid against a blockwork backing wall, which must be taken into cost consideration. Typical prices for natural stone vary, but expect to pay £100-£150/m2 including installation.
Installation and the mortar mix are critical to the success of your scheme. One good day out for those looking to find out more about stone, how it is laid and how different regions have their own localised versions is a visit to the National Stone Centre in Matlock, Derbyshire (nationalstonecentre.org.uk).
A cheaper alternative is to use a reconstituted stone. Although, to the practised eye, reconstituted stone will never look as good as the real thing, it will cost about half as much and, if done well, looks reasonably authentic. And because the product is manufactured, it’s easy to course and therefore much quicker to lay, which also saves overall costs.
One interesting alternative is to use reconstituted stone cladding. Fernhill Stone produces a very convincing product, which is set in moulds and is so realistic that it’s virtually impossible to tell apart from the real thing. It costs around £40-£52/m² plus VAT to buy the tiles. It can be placed on a polystyrene backing(useful for people building with insulated concrete formwork) but it’s usually stuck onto an outer blockwork wall. Fernhill Stone claim it’s a job that can be carried out by a competent DIYer or tradesperson. The recommended mortar depth is 10mm, and they come in a range of thicknesses up to 50mm.
There are plenty of interesting alternatives too. Haddonstone supply their cast stone, most commonly used for garden ornaments, railings and so on, as a custom cladding material. Prices start from between £7-£20 incl VAT for one of their TecLite blocks (444x219x25mm).