Victorian Brick and Tile Making

Friday, 14 November 2003 11:01 PM GMT

Contributed by: jami brooks

by Gilbert R. Redgrave from Cassell's Technical Educator. (Written in the late 19th century.)

Before passing on to the manufacture of tiles, it may be as well if we glance briefly at some of the many descriptions of bricks. These, as may be supposed, are almost endless, and we can only, in the space at our command, refer to a few of the chief of them. Coping bricks are used to surmount walls, and are so shaped as to throw off the water, and provide a slightly overhanging protection to the wall; they are therefore, generally rounded, or made with a slant or double slant at the top, and should be provided on their under surfaces with a slight groove on each side, in order to form a drip to throw the wet off the wall. They are seldom made for walls more than 14 inches in thickness, and should be one inch wider on each side than the wall - thus, 11 inches for 9 inch brickwork, and 16 inches for a wall 14 inches wide. Moulded bricks are made in every variety for enriched surfaces, and take their names from the shape of the principal moulding on them: arch bricks are those made in the form of a wedge, in order to serve as voussoirs; splayed bricks, such as have one of their edges canted off, and are employed for set offs and plinths; compass bricks, used for building circular walls and sewers; channel bricks, for gutters; clinkers, specially made for paving; and bond bricks, which are from 14 to 18 inches in lkength, and are used to improve the bond of common brickwork. There are also special names in different parts of the country for the various qualities of bricks, with reference to the respective excellence of their manufacture; thus the best, according to the nature of the brick, may be called malms, rubbers, or cutters; the seconds, stocks, or malm stocks, and grizzles; and the inferior and underburnt kinds, shuffs, sammel or place bricks. Those which are so overburnt and run together as to be quite valueless, are called clinkers or burrs, and are broken up and used for road making. In accordance with the way in which they are made, bricks are sometimes called pressed bricks, or patent bricks, which latter term is applied indiscriminately by bricklayers to all machine made bricks.

By the Act of Parliament now abolished, which imposed a tax of 5s per thousand upon all bricks under a certain size, and double this amount on all such as exceeded 10x5x3 inches, which are rather in excess of the dimensions of an ordinary brick, it was also impossible to go over or dress the surfaces of any bricks, after they had once left the mould, without rendering them liable to an increased duty of 12s per thousand. Under these circumstances, it is scarcely to be wondered at that for many years little was attempted in the way of improving this branch of manufacture. The Act of 1839, which made this duty a uniform sum for all bricks under 150 cubic inches in contents of 5s 10d per thousand, opened up an important and neglected industry, which has since then made great progress, and moulded and enriched bricks are now widely used for London buildings.
London, owing to the scarcity of stone in its vicinity, must always remain a brick city, and it is said, knowing this to be so, to see how little has been done by London brickmakers to improve the ordinary stock brick, which is about as bad as it could be.

Before concluding our remarks upon bricks, we may refer very briefly to the plan of using them as gauged or rubbed bricks. It was a very common practice in the "Queen Anne period" to put together a number of carefully burned bricks, picked for evenness of colour, with the thinnest possible joints, and then to carve some ornament on this mass, dealing with it as if it were a block of stone. For all the best kinds of walling, moreover, the bricks were similarly selected for colour, and rubbed on a stone slab, to make the joints as thin as possible. The face of the finished wall was likewise rubbed over with a hard brick, till it was perfectly level and true. Such work constitutes the fine old red brickwork, which is frequently so much praised. A somewhat similar mode of preparing and using brick is now again coming into vogue; and opposed as it is to the nature and properties of the material considered with reference to its brick origin, we cannot but protest against this method of dealing with brickwork. To cut and carve bricks into all kinds of elaborate shapes when they have been hardened into all kinds of elaborate shapes when they have been hardened into all kinds of elaborate shapes when they have been hardened in the kiln, and to do at so much expense, when the clay has been burned, that which could have been so readily and cheaply done while it was in the plastic state, appears to us to be entirely wrong and false in principle. It does not come within our province to point out the best modes of using bricks, nor have we anything to do with the mortar or cement used for this purpose. On the vexed question of thick and thin joints, we may state that we are of the opinion that a joint of about a quarter of an inch in thickness, as one which can readily be made with the ordinary consistence of mortar, and as furnishing a good and true bed for a fairly well formed brick, should be insisted upon. The plan of making bricks with a large frog or kick on their upper and under surfaces, and of filling some kinds of bricks with small perforations, while it is by no means injurious, decreases their weight, and gives the mortar a good hold. We may conclude this part of our subject with the following simple directions: "Well wet your bricks before laying them, and let your mortar be as stiff as possible."

We shall divide our observations upon tile making into two heads - namely, roofing and drain tiles, and flooring and wall tiles. Tiles specially intended for use as a roofing material have not, we think, the same antiquity as bricks. The ordinary roofing tile, known as a plain tile, which generally measures 101/2 x 61/2 x 5/8 inches, and weighs about 21/2 pounds, seems to have been made on the model of a shingle. Shingles are thin strips of split wood used in the same way as tiles are used, and which in many parts of Germany and Switzerland, and even in some of our own rural districts up to the present day, are in almost universal use for every description of roofing.

The introduction of slate, owing to the increased facilities of railway communication with Wales and other slate producing districts, seemed likely for a time to drive tiles completely out of the market. The weight of the tiles may be assumed to be about 15 cwt per square of 100 superficial feet, while the same amount of roof space could be covered with 5 cwt of the best slates. Then the slates are so much less porous, so much more readily fixed, and can be laid at so much flatter an angle than tiles, that for these and other similar reasons they have very largely replaced the old fashioned tiling. It cannot, however, be forgotten that slating is a very dull and ugly looking substitute for tiling, and as tile manufacturers have recently been exerting themselves to give us a better made and lighter article than the old fashioned pan or plain tile, we may hope to see tiles again largely used. Pan tiles are larger than plain tiles, have an ogee section, and weigh about 51/4 lbs each. Both pan and plain tiles, and several other varieties we shall allude to further on, are generally made by brickmakers, and require appliances similar to those described for brick making. Plain tiles can readily be made by machinery, but we are not aware that any machine exists for the production of pan tiles.

The clay for tile making requires to be of a tougher description than that used for bricks; and, as it will readily be understood, owing to the much greater thinness of tiles, requires a much more careful course of preparation. It is generally dug in the Autumn, and allowed to remain all through the winter months in shallow pits, to fall and mellow, and is sometimes kept for twelve months before it is used; it has to be carefully picked over to remove the stones, and it is generally tempered before use in small lumps by women or children, or it is passed twice, and sometimes three times, through a pug mill. Having been further prepared by cutting it into numerous thin slices with a wire cutter called a sling - which process assists in removing the small stones, and is similar to the wedging or slapping of the terra cotta clay - the clay is ready for the moulder. The lumps or pieces are roughly prepared by a boy in thin slices, about large enough to fill the mould, which is nothing more than a wood frame, a little over half an inch in thickness. Tiles are invariably made in sanded moulds, as slop moulding cannot be employed. In Staffordshire coal dust, and in Shropshire powdered burnt clay is used to facilitate the object leaving the mould. The clay having been filled into the mould, the surface is levelled, in some places with a wire cutter, in others with a round roller, like a cook's rolling pin. The tile is then removed to dry, and when partially dry it is beaten with a thwacker, or placed upon a horse, to give it what is termed a set. The set is a slight curve, which is necessary in order to enable the tiles to bed evenly one upon the other when used for roofing. When thoroughly dry, the tiles are stacked in kilns, and burnt as bricks are burnt. It is a very common practice to burn bricks and tiles together, the bricks being at the bottom of the kiln and the tiles at the top. The tiles are built up on edge, as close as they will lie, in layers or "bolts," which cross one another at right angles. When they are burnt alone they do not require so much firing as bricks, in consequence of their small thickness.

It was formerly customary to punch a couple of small square holes through the tile, about 11/2 inches in each way, at the top; through these holes wooden pegs were driven, by means of which the tile was hung upon the lath. This system has now been discontinued in most places, as not only was the tile much weakened thereby, and frequently broken by the insertion of the pegs; but it was also found that the dampness of the tile soon rotted the peg, which dropped off, and allowed the tile to slip off the roof. In lieu of the holes, therefore, a small stud or button of clay is cast on the under surface, just against the upper edge, which most effectually replaces the peg.

In making pan tiles, the tiles are first moulded flat, and then given their proper curve on a specially formed block. They arew subsequently, when partially dry, trimmed up and finished on a thwacking frame, and burnt in a special kiln. For a more minute description of what is, however, now an almost obsolete manufacture, our readers are referred to the article on "London Tileries"," in "Dobson's Treatise." In Shropshire and Staffordshire a very small and thin tile is made of the well known blue clay, which is burnt very hard, and which, owing to its imperviousness and lightness, makes an excellent roof material: such tiles are termed Broseley tiles.

Plain tiles are very frequently ornamented by having their lower ends made pointed or rounded off, and when used in alternative courses with common tiles, they have a very good effect. Such tiles are made in a similar way to the plain tiles, in a special mould.This kind of tiling is often used against bthe vertical wall of a house or cottage to keep out the driving rain, and in this form it is known as "weather tiling." The special tiles for covering the ridges and hips, and for forming gutters - known respectively as ridge, hip, and valley tiles - are hand moulded on blocks shaped for the purpose; they are about the same price as pan tiles. Ridge tiles are difficult to burn, and are generally placed one within the other on the top row of the kiln.

Drain tiles are properly small pipes: they were at one time made sectionally in the form of a horse shoe and were placed in the ground in the trenches prepared for them, with the open part downwards. In soft soils such draining was of very little use, as in a very short time the superincumbent weight pushed the tile down into the earth, and thus filled it up. These tiles, which were moulded flat and susequently bent to the required shape, are, we believe, now no longer made. The ordinary circular drain tile, which may be from 11/2 to 3 inches in internal diameter, is made in a machine of simple construction, which can be readily worked by hand. A man and boy can turn out 4,000 or 5,000 in the course of a day. Before the introduction of these machines a strip[ of clay had to be rolled out or moulded of the required size, and then wrapped round a drum or mandril, the edges closed by hand, and

after the tile had been shaped and finished the drum was withdrawn, and the tile stood upon end to dry.
There are numerous pipe making machines now in use which are almost exactly similar in principle: the clay is first prepared in a pug mill, and then pressed through an aperture in a steel die; the pipe is cut off from time to time, to any required length, by means of a wire cutter. Some machines make three or four tiles at each stroke of the piston. A comparatively recent invention is a machine for producing pipes by hydraulic pressure, which seems to work steadily and well. Pipes are stood on end, and built up one on top of another, in the kiln. If it is required to give them a salt glaze, the fires are made up just as the kiln has got to its full heat, and a few handfuls of salt are thrown on each fire. The salt sublimes, and the soda therin combines with the silica in the clay to form a fusible double silicate of soda and alumina. Salt glazing is, we believe, almost invariably confined to down draught kilns. A ring wall about half way up the kiln protects the goods from immediate contact with the flames, which pass up over this wall through the goods, and escape by means of numerous openings in the floor into the chimney. Pipes, tiles, and all thin clay goods, though they do not want quite so much care as more solid objects in the smoking process, require very careful and tender treatment under full firing.
In the production of simple ornamental roofing tiles some of our Continental neighbours are far ahead of us: there have been latterly, however, several new kinds of tiling brought under our notice. Among these are the corrugated tiles, made at Bridgewater, the Broomhall tiles, which are ribbed or fluted, and the so called Italian tiles, which are a combination of rolls and flat tiles. The true Italian tiles are all semi circular, and are laid alternately convex and concave. The mode of repairing leaky roofs in Italy may be all very well there, but would not do, we fear, with our lightly timbered English roofs. It consists in laying another layer of fresh tiles over the leaky ones, which are left as they are. We have seen old roofs inMilan with three or four thicknesses of tiling on them. For producing plain and moulded tiles by machinery the appliances are all of them similar to those peviously described for brick and pipe making. We shall pass on in our next paper to the manufacture of flooring tiles.

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