The tiles used in connection with buildings may be divided into two great classes.
1. Common tiles of different shapes used for roofing and paving.
2. Encaustic tiles used for decorative purposes.
Common Tiles are made out of somewhat the same material as ordinary bricks, but they should be purer or stronger clays - well worked so as to bear "thwacking," or they will be liable to lose shape in burning.
The clay is weathered either by exposure to frost or sun - allowed to mellow in pits - tempered - pugged, cleared from stones - moulded, trimmed with a knife - thwacked (that is beaten when half dry with a wooden bat to correct warping) and burned in a domed kiln.
Common tiles are made in a great variety of shapes, for roofing, paving, and other purposses.
Flooring tiles are sometimes known as Quarries.
Of these there are several different kinds, a few of which will now be described.
To prevent this they should be glazed, which involves reburn-ing and makes them expensive.
Many descriptions of roof tiles do not fit together very closely, and therefore require pointing to make a tight roof.
Plain Tiles are flat, either rectangular, or cut to various patterns. See Fig. 70
Each tile is pierced with two holes near its upper edge, through which small oak pegs are driven, by which the tile is hung on to battens or laths, nailed apart at the proper gauge, as described in Part II.
Sometimes the holes are omitted, or two little projections at the back of the tile are provided to take the place of the oak pins.
Figs. 70 and 71 are from page 264, Part II., where the method of laying these tiles is described.
Pantiles1 are moulded flat, and afterwards bent to the form shown in Fig. 72, over another mould.
Each tile has a stub, projecting about 3/4inch from the centre of the back of the upper edge of the tile, by which it is hooked on to the laths.
The method of laying these tiles is described at page 266, Part II.
Double Roll Tiles are like two pantiles joined together, side by side. They have three stubs on the back.
Corrugated Tiles are similar to pantiles, but each tile contains three or four corrugations, as in Fig. 73.
Improved Corrugated Tiles have flat pieces alternating between the corrugations.
1 Sometimes called Flemish Tiles.
Taylor's Patent Roofing Tiles, now known as the Broomhall Company's Patent Roofing Tiles, form a handsome roof covering.
The form of the tiles is shown in Fig. 75. They are laid alternately as capping and channel tiles, as shown in Fig. 76, in which T T are laid as channel tiles, while U, being a tile of the same form as the others, is reversed to fit over them as a capping tile.
A description of the method of laying these tiles has been given at page 266, Part II.
Venetian or Italian Tiles are of the form shown in Fig. 77, which is from page 266, Part II.
The snow is rather apt to lodge upon these tiles, and when it thaws to pass through the roof.