Slate Installation Tools and Materials

Slater's Tools

The tools commonly used by the slater are the punch, at the hammer, ripper and stake. If much punching is done at the yard or on the job by the roofer, a punching machine should be used for punching the nail holes and cutting the slates. It is adjustable to any size or shape, cuts and punches at one operation with a countersunk hole. The hand or mawl punch is forged from fine tool steel hardened and ground about 4 1/2" long with one end tapered. The butt end is struck with a mawl to punch the nail hole.

Slater's tools are all drop forged. An approved hammer is forged solid, all in one piece, from crucible cast steel, with an unbreakable leather handle to avoid slipping and blistering the hands. One end terminates in a sharp point for punching slate, the other in the hammer head. There is a claw in the center for drawing nails, and on each side of the shank there is a shear edge for cutting slate. The head, point and cutting edges are properly tempered to withstand heavy work. The slater's stock size hammer has a 12" handle.

The ripper is about 24" long and is forged from crucible cast steel. It is used for removing broken slate and making repairs. A hook on the end provides a means of cutting and removing the slating nails. The blade is drawn very thing and the hook end correctly tempered for hard wear.

The stake is about 18" long and T-shaped. The long edge is uses as a rest upon which to cut and punch slate or as a straight edge to mark the slate when cutting and fitting around chimneys, hips, valleys, etc. The short arm is tapered and pointed for driving into a plank or scaffold.

These tools, as well as 24" stakes, shorter rippers, left-hand hammers or special hammers or tools, can be obtained from any slate producer distributing roofing slate or from manufacturers of such tools. The slater's equipment is completed with a nail pouch, tinner's snips, rule and chalk line.

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Nails

Slate being a permanent material, is worthy of care and thought in the proper selection of the various materials used in connection with it, and especially as to the method of securing the slate to the roof construction.

Like any other construction unit, a slate roof can only be as strung and enduring as its weakest part, and the majority of slate roof failures over a period of years may be attributed to the punching of the nail holes, the nailing of the slates, or the nails themselves. As has previously been stated, the art of properly laying and nailing slate is not to be discounted and belongs to men trained especially in the work.

Before nails came into extensive use, the slate were held in place by means of wooden pegs driven through the slate and hooked over the roof lath. It is the practice in some localities today to hang the slate to the laths or battens by means of heavy wire hooked through the slate and over the laths. This method is in general use where the slate is laid directly on steel construction. Copper nails of sufficient length to be securely hooked and clinched over the structural angles may also be used. These should have large heads and the shafts be of No. 10 or 11 gauge metal.

Nailing is more extensively used today than other methods for securing the slate, and careful attention should be given the characteristics of nails selected for this purpose. The important considerations involved are shape, size and material.

For all practical purposes, the ordinary diamond point and smooth shaft are sufficient for slating nail and the needle point is seldom, if ever, necessary or of advantage. The shaft, since it supports a greater weight and must resist a small shearing stress, should be larger than that of the shingle nail. To prevent the slate from being lifted up over the nail after being laid, the diameter of the head should be greater than that of shingle nails.

The temptation to use shingle nails instead of slating nails should be discouraged, for the slight saving in cost on the entire roof cannot approach the cost of repairs which may develop as a result of this practice. Architects and owners should insist that the roofer used nails of proper size and kind of non-ferrous metals.

The much-mooted question of the material of which the nails should be made must remain a matter of opinion and judgement until an impartial investigation shall throw further light upon the subject.

It is hoped that research in this field may be undertaken in the near future and definite results furnished those interested. It is a generally accepted fact that copper is one of the most enduring of metals and that iron and steel, adequately protected from corrosion by a heavy coating of zinc applied by the hot-dipped process, will give reasonable service. Plain or ordinary galvanised nails should not be used for laying slate. Nails having a copper content, such as "yellow metal," or "Muntz Metal" and cut zinc nails are sometimes used. Nails should be carefully selected and be the best grade of a reputable manufacturer. Recently "Cimet," "Everdur" and similar chrome-iron alloy nails and other types particularly suited to resist atmospheric corrosion, have been put on the market. Their cost is higher than copper, yet for certain building with excessive or unusual acid fumes under and surrounding the slate roofs, it may prove economical to use such nails. Time and wider use of these newer types will prove whether they are or are not superior to copper. When cost is an item, the "Copperweld" nail, being less expensive than solid copper, is often used and may prove to be the satisfactory method of protecting the steel shaft.

Under ordinary conditions, it will be found satisfactory to use 3d nails for commercial standard slates up to 18 inches in length. Use 4d nails for the longer slates and 6d on the hips and ridges. Thicker slates require longer and heavier gauge nails. The proper size may be determined by adding 1 inch to twice the thickness of the slate. Where the through penetration of the sheathing will not ordinarily be seen, it provides evidence that nails of sufficient length were used. Thus a 1/4" slate will require a 4d nail which is 1 1/2" in length. Where the under side of the roof boards is exposed to view, as is sometimes the case of overhanging eaves, a nail of such length as will secure sufficient penetration but not be driven through the sheathing must be selected.

Nails suitable for roofing purposes are made in four forms, each of which has its advantages.

The common wire nail (Figure 29) is used generally for nailing flashings, sheathing, and sometimes for shining. It is not suitable for slate work, for it is of light gauge and small head.

The slating nail (Figure 30), as may be seen, is especially adapted for slating, as it is of heavy gauge and has a wide, flat head. These features make it much more desirable than the common wire nail.

The roofing nail (Figure 31) is not recommended. While the shaft is of proper thickness, its head is too small.

The cut nail (Figure 32) is made from sheets and is of quite different shape than any of those made of wire. The enlargement of the shaft gives it more stiffness than the wire nail has, but there is some danger of splitting the slate if too large a nail is used.

The following tables of slating nail sizes will be found useful in estimating or specifying:

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Roofing Felt

It should be emphasized that a standard slate roof can be laid water-tight on open lath without felt, as is often done in the South or on buildings where heat is not required. The thickness of the flat has little relation to the water-tight qualities of a slate roof. The opinion has been held by many that the thicker the felt, the tighter will be the roof. When it is realized that every nail used in fastening the slate is driven through the felt it will be seen how erroneous is this idea. Roofing felt, however, does have three other distinct uses in connection with slate roofs. The felt placed as soon as the roof is sheathed will protect the building, when necessary, until the slates are laid

It has considerable insulating value in resisting the heat of the summer sun and the transference heat from the inside during the winter months. Increasing heating costs in the colder localities makes this a factor worth careful consideration. The use of laths over the felt and under the slates to obtain an air space, a method recommended by English roofers, adds much to the insulation value of the felt.

The third value of the felt is to form a cushion for the slate. While not of great moment in the case of commercial standard slates, its value in this respect increase as the thickness and weight of the slate increases. For the commercial standard slate felt weighing 14 pounds per square will be found satisfactory. The same weight is ordinarily used under Textural roofs. Any of the heavier weight felts, as 20, 30 or 40 pounds per square, may be used where the appropriation allows. For Graduated roofs, the 30 pound weight is commonly used when the slates are 3/4" or less in thickness and the 50 pound for slates 1" or more. It is customary in some localities to place two layers of felt under the slate on a Graduated roof. The first layer is usually 30 pound felt and the second 14 pound. This provided an extra cushion for the heavy slates. The joints and laps should always be staggered.

The felt should be laid in horizontal layers with the joints lapped toward the eaves and at the ends. A lap of at least 3" should be used and the edges should be well secured to the surface over the metal lining of valleys and gutters. If metal other than copper is used as a lining the felt should be omitted in the valleys. Extend the felt over all hips and ridges at least 12" to form a double thickness.

Asphalt saturated rag felt should always be used. The so-called "Slaters'" felt includes many types of materials which cannot be recommended.

The article above explains important information regarding tools and materials used in Slate Roofing, Roofing Slate, Natural Slate, Chinese Slate, Roofing Supplies, Slate Installation, Foreign Slate, Stone Slate, Roofing Tiles and Slate Flooring. You can also contact us for more details.