The patent slating may be laid so as to be perfectly water tight, with an elevation of the rafters considerably less than for any other slate or tile covering ; a rise of two inches in each foot of the length of the rafter being deemed sufficient ; and this, for a rafter of fifteen feet, would be only two feet six inches, a rise in the pitch of a roof, which, on any height from the ground, would be hardly perceived.
Slating is done also in several other ways, but the princi ples before explained embrace the most of them. Some workmen shape and lay their slates in a lozenge-form. This kind of work consists in getting all the slates to a uniform size, and the shape of a geometrical square ; when laid on the roof, (which is always boarded for this work,) they are bonded and lapped as in common slating ; observing only to let the elbow, or half of the square, appear above each slate that is under it, and to be regular in the courses all over the roof. One nail or screw only can be used for such slating, hence it soon becomes dilapidated. It is commonly employed in places near to the eye, or where particular neatness is required.
Slaters' tools consist of a few only, which are sometimes found by the master, and sometimes by the men. The tool, called the saixe, is composed of tempered iron, about sixteen inches in length, and two inches in width, somewhat bent at one end, with a beech handle at the other.—This instrument is not unlike a large knife, except that it has on its back a projecting piece of iron, about three inches in length, and drawn to a sharp point. With this tool, ground sharp, the slater chips or cuts all his slates to the required sizes.
The ripper is of iron, about the same length as the saixe, and very thin in its blade, which is one inch and three-quarters wide, tapered somewhat towards its top, where it has a round head projecting over the blade about half an inch on each side, and having also two little round notches in the two internal angles, at their intersection. At the handle-end of this tool there is a shoulder, which raises it up above the blade, and enables the workman to hold it firmly in his hand. The use of this tool is in repairs of old slating, as by forcing up its blade under the slates, the projecting head catches the nail in the little notch at its intersection, and enables the workman to pull it out, at the same time that it loosens the slate, and allows him to remove it, and insert another in its place.
The slater's hammer is somewhat different in shape from the common tool of that description ; it is on the hammer, or driving part, about five inches in height, bent on the top a little back, and ground to a tolerably sharp point ; its lower or flat end being about three-quarters of an inch in diameter, and quite round. On the side of the driving part is a small projection, with a notch in its centre, which is used as a claw to extract such nails as do not drive satisfactorily.
The shaving-tool is used for getting the slates to a smooth face for skirtings, floors of balconies, &c. It consists of an iron blade, sharpened at one of its ends like a chisel, and mortised through the centre of two round wooden handles, one of which is fixed at one end, and the other about the middle of the blade. The blade is about eleven inches long, and two inches wide ; the handles are about ten inches long, so that they project four inches on each side of the blade. In using this tool the workman takes it in both his hands, placing one hand to each side of the handle in the middle of the blade, and allowing the other to press against both his wrists • in this manner he works away all the uneven parts from off the surface of the slate, and gets it to a smooth face.
The slater's other working tools consist of numerous chisels and gouges, together with files of all sizes, with which he finishes his slates for the better parts of his work into mould and other forms.
Slates are also fashioned into chimney-pieces, partaking of the different varieties of labour applied to marble ; but it is incapable of receiving a polish like it, except by japanning. It makes excellent skirtings of all descriptions, as well as casings to walls where dilapidations, or great wear and tear, are to be anticipated. It is capable of being fixed, for these purposes, with joints equally neat with wood, and may be painted over if required, to appear like it. Staircases may be executed in slate, and will have an effect not unlike to black marble.
Slaters' work is measured by the surveyors, as most arti ficers' work now usually is, and is afterwards reduced into squares, each square containing 100 feet superficial.
Slaters are allowed, in addition to the nett dimensions of their work, (when taking the measure of roofs,) six inches for all the eaves, and four inches for the hips ; this allowance is made in consequence of the slates being used double in the former case, and for the waste in cutting away the sides of the slates to fit into the latter. Some of these eaves, for in stance, when rags or imperial slates are used, require an addi tional allowance of nine inches for the eaves, such kind of slates being so much larger than the size of most of the other kinds now in use. All faced work in slate skirtings, stair cases, galleries, &c. is charged by the foot superficial, without any addition. Chimney-pieces are made up and sold at per piece, by the masons.
The following Table of Comparisons will be found useful :