The history of clay tiles
Clay has a rich global history going back to the earliest days of the roofing industry – and it continues to enjoy popular appeal for roof builders and homeowners alike, today and into the future.
Clay tiles have been around since around 2700 BC and were first introduced in England by the Romans. They form an important part of our architectural heritage and to this day, alongside slate, remain a standard tile for the roof industry.
When most of us think of clay tiles it’s likely our minds drift to a quintessential English scene; rows of houses with distinctive red roofs, made up of evenly distributed straight edged tiles.
It’s a well established fact that clay tiles have been a fixture of our local landscape for hundreds of years. In fact it’s probably fair to say that clay has been a staple of the roofing industry across the world for about as long as people have been putting roofs on their dwellings.
Certain forms of clay tiling were used on the roofs of some ancient Greek houses; and the material was also favoured by Egyptian builders of the time, as well as the Romans who adopted a typically innovative ‘over and under’ structure – a flat tray with curved sides would be laid against the roof while a cylindrical tile was overlaid to cover the joints and create a waterproof roof. However the practice of clay tile prodcution died shortly after their occupation ceased, with thatched roof dwellings becoming the standard on homes and buildings throughout England for the best part of 400 years.
The use of clay as a roofing material wouldn’t feature upon the English landscape with any prominence until the 13th century. The tiles of this era were simple in design – flat rectangles, conveniently sized and referred to as peg tiles, they had small holes at the edge into which pegs were inserted to hold them in place. They were laid in an overlapping fashion flat to the roof structure, much as you might find tiles laid in the centuries that followed after.
In light of the Great Fire of Southwark in 1212 AD it was decreed that buildings in the city adopt clay tiles as they presented less risk. Similarly, in light of the fire and potential risk that thatched roofs presented in a built up area, the Archbishop of Canterbury ordered all buildings in the vicinity of the church to adopt clay roof tiles from that day forth. These decrees initiated mass use of clay tiles across the country, with a standard size fixed into law by Edward IV in 1477.
In the decades and centuries that followed, the distinctive red and orange tiled roof would become the main feature of rural and urban living.
The British Standard for clay plain tiles was published in 1935 and with minor adjustments it remained in force until it was replaced by the European Standard in 1999.
To this day clay, alongside slate, remains a standard tile for the UK roof industry. Design and technology has brought improvements to their efficiency and installation, but much of their appeal, their durability and rustic charm and attractive colours especially, has endured through the ages.
In a Roof Tile Association survey of conservation offficers, planners, architects, house builders, surveyors and roofing contractors, 99% agreed that clay tiles enhance the built environment with 95% acknowledging that they are sustainable building products.
Roof tops across the country still appeal thanks to the distinctive reds of English clay from new homes to the restoration of period buildings.
Strength and durability
Plain clay tiles offer superior strength and durability than all other roof coverings. Many examples exist of roofs with plain clay tiles that are still standing in pristine condition after more than 100 years. The permanence of the colour with naturally burnt clay colours guarantees that the roof will never look washed out and as it ages it will improve and mellow.
The overwhelming case for plain clay tiles rests upon aesthetics. The wide range of natural burnt colours from Red to Brown to Blue can be imitated but never reproduced with artificial colouring. The permanence of artifical colours is not guaranteed.
The small size of plain clay tiles provides the versatility for the architect to design roofscapes of infinite interest. Large format roof tiles simply do not offer this flexibility.
Clay tile roofs form an important part of the architectural heritage of the UK. Planners and architects keen to preserve regional distinctiveness are keen to specify clay roof tiles.
Plain clay tiles are a sustainable product, the longevity of clay means that the energy and raw materials used in their production are offset over the whole life of the roof, which in the case of most clay tile roofs, is over 100 years.
Peg Clay Roof Tiles
Peg tiles retain their popularity due to the simplicity with which they have been made and fired and for aesthetic reasons which result in subtle variations which are not repeated by modern manufacturing methods.
Hand-made tiles are made from clay prepared in the mass from which a piece is cut by hand and pressed into a simple flat rectangular piece with two holes.
Peg tiles are normally provided with two holes at the head of the tile, one on either side of the vertical centre-line of the tile where the joint of the upper two tiles occurs when laid. These holes are formed by simply poking through the tile with a suitable slightly tapered device in such a way as to avoid splitting the unburnt clay.
As originally devised, the peg holes should be roughly rectangular, the holes would be approximately 8mm wide although variations to 15mm wide are notuncommon, varying even within a district of origin. The tapered device facilitateswithdrawal from the clay when the hole is made. The tapered hole is provided to allow a wooden peg to suitably wedge into position. A roughly prepared wooden peg is also more secure in a rectangular hole.
Often aluminium pegs are now used instead of wooden pegs.
Historically, each locality where peg tiles have been traditionally made and used will have its own size of tile, probably determined by the type of clay used and the incidence of loss due to firing. These tiles were made at local brick and tile yards, often on country estates.
Kent peg tiles are usually 9.5 inches (240mm)in length whilst Sussex peg tiles are more likely to be 10 inches (250mm) in length.