The second class of bricks includes the bulk of those required for building. The qualities and characteristics of these vary, not only in different localities, but also in the same brickyard (see p. 105).
Such bricks are made either from washed earth or malm, from partly washed earth, or from earth which has merely been tempered, not washed at all.
They should be hard and well shaped, those most uniform in colour being selected for facing, and the whole of the remainder being fit to use for good sound work.
The underburnt bricks of the third class are generally known as grizzle or place bricks, in some places as samel bricks.
They are always soft inside, and sometimes outside also, are very liable to decay, and unfit for good work.
They are, however, often used for the inside of walls.
As before mentioned, the names given to different classes of bricks vary in different districts, and even in different brickfields of the same district.
The subjoined list of the names for clamp-burnt bricks, adopted in a Kentish brickfield supplying the London market, may be taken as a specimen.
Following it is a description of some of the more important varieties.
The bricks are divided generally into three classes - Malms, Washed, and Common - according to the manner in which the earth for them is prepared (see p. 91). For the third or Common class the earth is not washed at all. All three classes are moulded and burned in exactly the same manner, and are then further sorted into a number of varieties according to the manner in which they have been affected by the fire-
The classes are subdivided as follows : -
Price per Thousand at Brickfield.
Best Seconds .
Brown Facing Paviors
Hard Paviors .
Bright Stocks .
Rough Stocks .
The prices above mentioned were those current when these Notes were revised. The prices vary of course from time to time, and depend upon seasons, etc. The differences between them serve, however, to show the relative value of the different classes of bricks.
Of the above classes cutters have already been described.
Seconds are similar to cutters, but with some slight unevenness of colour.
Bright Fronts are the corresponding quality from "washed" earth.
Facing Paviors are hard-burnt malm bricks of good shape and colour used for facing superior walls.
Hard Paviors are rather more burned, and slightly blemished in colour. They are used for superior paving, coping, etc.
Shippers are sound, hard-burned bricks, not quite perfect in form. They are chiefly exported, ships taking them as ballast.
Stocks are hard-burned bricks, fairly sound, but more blemished than shippers. They are used for the principal mass of ordinary good work.
Hard Stocks are overburnt bricks, sound, but considerably blemished both in form and colour. They are used for ordinary pavings, for footings, and in the body of thick walls.
Grizzle and Place bricks are underburnt. They are very weak, and two out of five "common" or unwashed place bricks are allowed to be bats, the stones left in the unwashed earth making them very liable to breakage.
Chuffs are bricks upon which rain has fallen while they were hot, making them full of cracks, and perfectly useless.
Burrs are lumps of bricks vitrified and run together. They are used for rough walling, artificial rock-work. etc.
Bats are broken bricks.
Of the above varieties those from "common" or unwashed clay are hardly ever quite perfect in form on account of the stones left in the earth, which make them shrink unequally, and become distorted in burning.
Bricks from "washed" clay suffer in the same way to a less degree.
Kiln-burnt bricks are generally pretty equally burnt, and are classed chiefly according to the process by which they are made.
Thus in one yard the classification is as follows : -
Patent bricks. Common hand-made. Copper moulds. Pressed bricks. Dressed pressed bricks.
In another yard the classes are Best white pressed. Second do. do. Pink do. do. White wire cut. Second do. do. Pink do. do.
The Burham Company's bricks are thus classified in their circulars : - No. 1. Pressed Gault (Facing).
2. Do. (Mingled).
3. Do. (Paviors). No. 1. Wire Cut (Facing).
2. Do. (as they rise from kiln).
3. Do. (Mingled or discoloured).
The bricks used in ordinary buildings generally are, or should be, the best that are made in the neighbourhood.
Some descriptions of bricks, however, are universally known, and are used even outside the locality in which they are made, either for special purposes, or in buildings of such importance as to justify incurring the expense of carriage.
A few of the more important of these varieties may now be noticed.