Primitive homes and buildings were roofed with whatever materials were readily available and close at hand. One of the earliest materials used in roofing was natural hand-split slate, which was widely used in areas with large quantities of underground slate quarries. In the North-West and South-West of England, Wales and Scotland, natural slate is predominant material used today. In more central areas of England, such as the Pennines and the Cotswolds, the local material used was heavy stone slate, which is also commonly used today.
Clay tiles were used in England by the Romans, specifically, of the ‘over and under’ (or ‘Tegula and Imbrex’) variety. After the Romans left the country, the art of making these tiles was lost and only a few monasteries continued to make clay tiles for their own personal use – a traditional that continued on until the 12th century. These simple tiles were rectangles of clay with nibs that were pressed out by hand. As they were easy to manufacture, some people sometimes made them smaller in order to save on production costs. This caused King Edward IV to pass a law in 1477 to standardise their minimum size. This was 10.5 x 6.5 inches (often referred to as ten and half by six and a half tiles) – and remains the standard clay tile size since. Following the Great Fire of London in 1966, thatched roofing was no longer allowed in London, and clay tiles were used instead, chosen for their obvious fireproof qualities.
Around the 16th century, overlapping tiles were re-introduced to the UK from The Netherlands. These tiles were linked together using an ogee, or an S-shape into one tile, rather than relying on vertical overlaps of two. These tiles became known as pantiles. To construct a roof using flat clay tiles, you would need around 60 tiles per square metre, whereas you would only need around 15 pantiles per square metre – allowing for considerable savings in labour time and weight. There are early records of pantiles being imported to the UK from The Netherlands, as it was some time before pantiles were being manufactured here. Early pantiles were irregular shapes and not very efficient at keeping rainwater out – so they were often used on buildings such as cowsheds. There are still some examples of old farmhouses that are roofed with natural Welsh slate, while their outbuildings use pantiles.
Alongside clay tiles, another popular roofing material is natural slate. In the mid-19th century, slate began to be used widely outside of its native areas with the growth and development of the railways – allowing for easier, faster and cheaper transportation of the slate tiles from place to place. Previously, slate had only been used on more expensive houses and public buildings, due to its price, but with the adventure of the railway, slate began to be used on mass housing – this can be seen today in most inner-city areas and suburbs.
During the first half of the 20th century, clay tiles changed yet again. Instead of continuing to use the ogee, or S-shape – tiles were designed with raised weather-bars which could interlock in order to create an even tighter waterproof seal. However, these developments occurred within mainland Europe, so between the two world wars, tiles flooded in from other countries – mainly Belgium. Tiles such as the ‘Courtrai tile’ and the ‘Marseille’ shape quickly became known within the British roofing industry.
With such aggressive competition coming in from abroad, the British clay pantile industry had all but disappeared by the 1950s. A combination of variable product quality and an inability to keep up with the demand from the booming housing industry destroyed their reputation. By the 1960s, many architects believed that clay pantiles were no longer available in Britain, when in fact a handful of smaller companies continued on, despite using out-of-date techniques and only being able to offer lengthy delivery periods.
It was concrete tiles that gained the upper hand in the UK around this time. Concrete tiles were originally introduced in the 1920s, but failed in becoming popular. However, after World War II, a huge rehousing programme was started, causing demand to rapidly increase. Whilst we in Britain invested in methods for faster and more automated production methods for concrete tiles, other European countries did the same for their clay tiles. 1960s concrete tiles were much more regular in size and shape than previously used clay tiles – which caused roofing contractors to favour them as they were easier to affix to the roof.
It wasn’t until the 1970s that the renaissance of the clay tile industry began. New technology such as the French computerised kiln firing and German machine pressing technology allowed clay tiles to be manufactured much faster and more efficiently. The shape of tiles became more regular, they could be manufactured in larger sizes and much cheaper, they no longer suffered from damage caused by exposure to ice and frost and their supply was much more reliable due to the fact the tiles were no longer dried out in outdoor sheds and potentially exposed to varying temperatures and bad weather.
From the 1970s onwards, there was a slow but steady recovery in the manufacture of clay tiles and slates, but it wasn’t until recently that the dominant concrete tile industry was challenged. Major investments in new, efficient clay tile factories led to the introduction of a wide array of new innovative products that made clay tiles more varied and affordable than ever. This has lead to a resurgence in clay tiles, as well as a boom in slate as new, cheaper slate imports began arriving from overseas. These developments have combined to create a renaissance in natural roofing materials in the UK.