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Malleable Iron, has recently been recommended, for the roofsof large buildings; but is not applicable to houses of a moder-ate size. It is sometimes used in thin plates, betwixt iron joist-ing and rafters, to shut out communication in case of fires.
Chap. III. App. No. 3.
Of Floors formed of Clay, Composition, Stone,Brick, and Wood.
I. Clay floors, are the least expensive, and on that account aremade for barns, cottages, &c. when more expensive materialscannot be afforded. All clay floors require to be kept dry; for•which purpose, the area on which they are to be formed, shouldbe carefully drained of all moisture ; and, unless the soil con-sist of dry sand, gravel, or rock, the space should be broughtto a proper level with chips of stones mixed with pounded bricks,or forge ashes. The depth of the clay, not to be less than three,but rather six inches ; which should be previously prepared, inthe same manner as for bricks, by long exposure, and frequentbeatings and turning over. When making it up for the lasttime, before laying on the floor, a quantity of straw should bethoroughly mixed into, and beat together, with as little moisturein it, as is possible to keep it in a solid body, which will pre-vent its opening into chinks in the drying. It should be beatdown on the floor with a rammer, and smoothed with a heavyroller.
As floors formed of clay only are easily affected by moisture,a better floor will be formed, by making the first layer, as de-scribed above, omitting the straw, and rutting it across with atrowel, in the same manner as is done with the first coat of plas-ter on walls, but the ruts made deeper. A mixture of clay,brick dull, or burnt fand and pounded forge afhes is then to bewrought up for the upper ftratum, and mixed with flacked lime ;the whole thoroughly mixed and beat up, afterwards formed into aheap, and left for a few days, when it fhould be again beat up,fpread compadlly on the floor, and made as fmooth as poffible.
Floors formed of clay, and rods for lofts and upper floors of cot-tages and outhoufes, are defcribed in Marfhall’s Rural Economy ofNorfolk, Vol. II. p. 24 , and have fince been put in praftice by MrErfkine of Mar, in the following manner: The rods being trim-med, (namely, the twigs and tops taken off), they v/ere laid acrofsthe joists, as clofe to each other as poffible; if crooked, they were* crippled, ’ had a chop in the crooked part, with a hook or hatchet,fo as to make them touch every joift as well as each other ; no nailsor other confinements.
The clay being well foaked in water, the principal part of it wasmixed with long wheat flraw, which was well wrought into it, bythe means of a borfe or man treading it, ayd by racking it about