The History of Tiled Roofs

THE PLAIN TILE IN ENGLISH ARCHITECTURE
Dr. R. W. Brunskill

What's in a name? Roman tiles, Italian tiles, Spanish tiles, even pantiles have something more than a mere name. But the humble plain tile is just plain. Yet the name derives from Latin and was used in medieval documents to describe the 'plane' or flat tile of baked clay as distinct from the various curved tiles which were also used. It is the name still applied to one of the most widespread as well as one of the most versatile of building materials available for covering our roofs and our walls.

The word 'tegula' or tile was used to describe several clay products in the early Middle Ages including bricks and paviors as well as roofing tiles but the special word 'thacktyle' was used certainly from the year 1212 and possibly from as early as 1189 in London. As the term suggests, tiles were used as an alternative to thatch where a more long-lasting, a more uniform, a more predictable, and, above all a more fire-resistant roof covering than thatch or reed or straw was required. This was especially true of urban buildings. Squeezed within their defensive walls, medieval towns were crowded with timber-framed buildings covered with thatch and therefore vulnerable to the spread of fire from roof to roof. From an early date various municipalities attempted to counter the danger by legislating for the use of tiles. Use of plain tiles rapidly spread in town and country until by the 18th Century these were the normal roofing material for a third of the country.

The shape of the plain tiles is sometimes held to derive from the shape of wooden shingles, another alternative to thatch but one almost equally as vulnerable to fire. Many attempts were made to regulate the size of plain tiles. The best known is that made by statute in 1477/8 during the reign of Edward IV in which it was required that a plain tile should be 10½" long by 6¼" wide (most plain clay tiles of the present day are 10½" long by 6½" wide). Since tiles were sold by number, unscrupulous tile-makers were inclined to skimp on dimensions while the building owner expected to have to use the minimum number of tiles to cover his roof. The statutory size made an acceptable compromise though the limitations of a manufacturing process which depended on a mixture of judgement and chance meant that nominal dimensions could not always be maintained.

Bricks and tiles were generally manufactured together. Both tiles and bricks were normally made from clay dug close by the site of the intended buildings, worked and tempered and then burnt in a clamp or kiln made at the building site. Each individual tile was made by hand; it was not until well into the 19th Century that tile-making machines came into use and then more often for pantiles or other shaped tiles than for plain tiles.

From 1784 onwards the price of tiles was affected by the Brick Tax introduced by William Pitt the Younger along with several other ingenious taxes to help defray the cost of fighting the American War of Independence. Taxation records give some idea of the numbers of bricks and tiles manufactured at that time. In 1833, for instance, over 42,000,000 plain tiles were subject to the levy and, while they were produced in many counties of England, the largest producer was Staffordshire with nearly 8,000,000 made at that time. The tax on tiles was in fact removed in 1833; bricks had to wait until 1851 until they were free from tax.

At this time there was competition between tiles and slates for the roofing market and although slates were not taxed as such they were subject to the tax on coast-wise shipping since most were transported by water from the quarries in North Wales and the Lake District. Traditionally, plain tiles were hung from laths. Each tile had two holes formed near its head. Oak pegs, pushed through one or sometimes two of the holes, were hooked over the laths made of riven oak and nailed to the rafters. In plain tile roofs the position of the hole varied, the shape of the peg varied, the thickness and contour of the lath varied and the rafters varied in size. The tiles were curved in length and had a varying curve in width. Whatever the uniformity of size in the tiles the resulting roof was far from uniform in surface and appearance.

From about 1840, following a patent granted in 1836, there developed the practice of including one or two nibs at the head of each tile in order to hand the tiles from machine-sawn laths. Only certain courses of tiles at the eaves and at levels up the roof were nailed into the laths. A greater degree of uniformity was one result of this changing practice though, in fact, tiles with nibs did not come into general use until late in the 19th Century.

Normally tiles were bedded in some material which would help to keep out draughts and make the roof resistance to the danger of driven snow, a danger which applied even though most plain tiles roofs were laid to a pitch of at least 45deg. The cheapest bedding was hay or moss; it had the advantage of resilience and thickness but needed frequent attention and renewal. Lime mortar was an alternative bedding material and many plain tiles stripped from roofs for possible re-use show signs of this mortar bedding.

In many parts of the eastern and south-eastern counties of England plain tiles were used for wall cladding as well as for roofing. They were especially popular in Kent, Sussex and Surrey. Hung on laths nailed to new or existing timber-framed walls they provided a neat, up-to-date, durable and fire-resistant cladding to such buildings. Shaped tiles giving a scalloped or fish-tail shape were also used alone or with plain roofing tiles.

With clay plain tiles we have an agreeable balance between uniformity and variety. Uniformity comes in shape, size and depth of lap as well as in colour to a certain extent; variety comes in texture both bold (in variations in surface) as well as fine (in the sandy texture of each tile) and in detailed variations in colour from mix and firing and in the way light catches the expanse of a tiled roof. With uniformity and variety in due proportion comes versatility: tiles may follow roof shape or wall shape, tiles may follow ridge or hip, tiles may be laced or swept or moulded up valleys in roofing. Plain tile and brickwork go together in being essentially the same material with the same basic method of manufacture and similar degrees of uniformity, variety and versatility. A set of brick walls with a clay tile roof is of the essence English and very far from plain.

NOTE: This Chapter of the CRTC 'Plain Tiling Guide' is an edited version of a paper prepared in 1985 by Dr. Ronald Brunskill, Reader in Architecture at the University of Manchester, one of Britain's leading architectural historians and the author of many publications on traditional building.