A roofing material should not be judged by its first appearance, but rather by its condition after four or five winters have passed over it. And in choosing the roof for the small house, this is a statement which applies with even greater emphasis, since the temptation is magnified to select that material which is low in cost and bright upon its first appearance.

As an illustration, there are certain types of wood-shingle roofs which have a charm in the beginning that is apt to disappear with age. These are constructed of shingles, dipped in many varieties of colored creosote stains, browns, reds, greens, blues, yellows, and the like, and when newly laid have a warm, mottled, and colorful texture which suggests the multiplicity of tone that nature often produces with age. In fact, the designer who originated this roof was trying to imitate the aging effect of nature, much as Tiffany glass is an imitation of the effect of time upon certain ancient glasses; only in the latter case the operation is the same but the time element reduced, while in the case of the roof it is a theatrical imitation of nature at work.

And there are many other fads in roofing, all of which have as their basis the imitation of the weathering effect of nature. Ridge-poles are constructed with a sag to resemble the settlement which is often observed in picturesque old houses. Shingles are laid, like the scales of an armadillo, and ridges, hips, and eaves are rounded to present the appearance of old thatched roofs. Asbestos shingles are broken with rough edges, and defective tiles are used—all for the purpose of giving that ragged appearance which nature develops with age. Now, to a certain extent there is an element of architectural truth in such devices, but they should be used with the greatest discretion, for, as has been previously asked: “If a roof looks old when it is new, how old does it look when it really is old?”

Before discussing the various methods of laying roofing materials, let us observe some of them after they have been on the house for a few years.

Of course, we are all familiar with the short life of the wooden shingle, which is only about fifteen years. But the life can be extended by dipping them into creosote stains, either just before laying or by the more convenient processes of factory dipping. Cedar has been found to be the best wood for these shingles, since it has a natural resistance to decay. The old hand-split shingles were more durable than the modern shingles, for the surface that they exposed to the weather was the natural cleavage plane of the wood fibres. The sawed shingle delights in curling and twisting out of a flat plane, and always seems to split so that the crack lines up with the space between the shingles on the course above, thus permitting the rain to leak through. And then the nails either rust away or the wood rots around them, until individual shingles drop away from the others, leaving small or large holes in the roof. It is well recognized that the sparks from a neighboring fire find a ready meal in the punk and rotten butts of the shingles, and many a house has been burned to the ground because of this.

The nearest competitor to the wooden shingle in cost is the asphalt shingle, which is made from roofing felt, saturated with asphalt compounds, and surfaced, under pressure, with crushed slate of greenish or red hue. The life of these shingles depends a great deal upon the thickness of the body. Some roofs, laid with very thin asphalt shingles, develop an appearance of chicken-pox after a year or two, for the heating effect of the sun, the lifting force of the wind and ice cause certain individual shingles to bend up from the plane of the roof and, in extreme cases, even flap in a heavy gale, like so many small pin-feathers. But this is not so true of the thicker grades of these shingles. Often, too, these asphalt shingles bulge under the hot sun, but this is due to careless laying, for each shingle should be separated from the other by a small space to allow for this expansion. It takes a good many years for the crushed slate on the surface to wear off, but gradually this happens, as also the elasticity of the body degenerates. Finally, as the surface begins to moult, the shingle itself becomes stiff and brittle and begins to break off. Of course, these shingles are superior to wood in resisting sparks from a near-by fire, and their life is longer, if they have a thick enough body.

That same material used for asphalt shingles is made into roll roofings. So-called shingle strips are made, which consist of long, narrow rolls of asphalted felt with the crushed slate surface, the lower edge of which is cut out to form the lower third of the shingles, and, when applied to the roof, the appearance is identical to a roof laid with individual units. Another type of roll roofing is made to imitate wood shingles, by having a shingle pattern stamped with black asphalt upon the surface of crushed slate. It is laid on the roof from the ridge down to the eaves, lapping joints with the next roll about two inches. At a distance the black pattern gives the camouflaged appearance of a shingle roof. The chief objection to any of these roofs is that the long and large areas are nailed down along the edges so that the sag and expansion of the material raises little bumps and hills over the entire roof, which, to say the least, is very unsightly. Then, again, the nails are exposed, and unless they are copper, the chances are that they will rust away before the roof is worn out, permitting the edges to become loose and the wind to get under the material and rip it away from the roof. Moreover, the roll roofing has only one thickness at any point, while the shingle roofing has either two or three layers over the entire area of the roof.

The cheaper grades of slate roof, such as one would be tempted to use on the small house, show weaknesses in aging that should not be used as arguments against slate roofs in general. These cheap roofs are built up of poorer grades of slate, and very thin sheets at that, and a poor grade of nail is used. The effect of weathering on such roofs is to chip off pieces of slate and to rust the nails, so that whole units drop off. Generally, too, in these cheap slate roofs, the tar paper is omitted from underneath, and the wind suction through the roof draws the snow through the cracks onto the floor of the attic, where it melts and stains the ceilings below. However, properly selected and well-laid slate roofs have none of these disadvantages, but then the cost of them is generally a barrier to using them on the small house.

As with the slate roof, so with the tile roof, the cost is generally the reason for not selecting it, and yet, from an economical point of view, in the end they are not as expensive, since with the less durable roofs one is never sure of how much damage to the interior a leak will cause. Tile roofs of poor quality have as bad reputations as slate roofs. Small, thin tile are very brittle, and falling limbs and other objects often break individual tiles, and it is very hard to replace them. Unless the tile are laid upon a building-paper the wind suction is even worse than with slate roofs.

Probably the greatest defects in tile or slate roofs is not in the material itself, but in the flashings and valley construction. Instead of using copper the flashings are usually of tin, which is permitted to rust out because of neglect in painting. Leaks develop in the valleys and around chimneys in spite of the roofing material.

While asbestos shingles can show great practical durability, even superior to slate and tile in some cases, yet there are many instances of ugly weathering. Tile and slate roofs develop warm, lovely tones with age. Asbestos shingles, since they are chiefly made from cement under pressure, must necessarily depend for their color upon inert pigments introduced into their composition at the time of manufacture, and for this reason their color is apt rather to fade than become richer with age. Their tendency is to return to the natural color of the cement. For this reason we see on every hand red asbestos shingle roofs which have bleached out to sickly and thirsty pinks, and brown roofs that have blanched to whitish-brown, much like the color which chocolate candy develops when it is very stale. Then, too, certain makes of asbestos shingles show, as time goes on, salt-like deposits on the surface, like the whitewash which appears upon brick walls. This gives a motley appearance to the roof, for some shingles will develop this white stain more than others.

The reader should not draw from these statements the general conclusion that the asbestos shingles should not be used, and that there have been none made that overcome the above difficulties, but it would be well for him to observe these defects before deciding upon any one brand.

The manufacturers of tin advise that the tin be painted on both sides when laid, and thereafter kept painted at four to five-year intervals. In other words, the tin roof is as good-looking as the paint which covers it, for it has no color or texture of its own. Can there be much charm in a roof of this kind? Can one picture a cosey and homelike small house with either a flat or standing seam tin roof? Perhaps the flat decks which do not show are satisfactory, when covered with tin, but those upon which any walking is to be done should be covered with wood lattice or else the nails of the shoes may punch through the tin and cause a leak. Tin roofs have their place and their duty to perform, but they are hardly suited to flat roofs over which is to be done much walking. Heavy deck canvas, laid in paint and covered with paint, is the best for this purpose. The ferry-boats give evidence of the practical wear of this kind of roof.

Tin or galvanized-iron shingles or imitation tiles are often seen applied to the roofs of small houses. The owner probably admired a real tile roof, and the nearest approach his pocketbook would permit him to come to it was the use of imitation tile of tin, copper, or galvanized iron. Most architects ridicule this peculiar weakness in human nature which chooses imitation diamonds, glass pearls, oil-paper stained-glass windows, and pressed-metal tiles, instead of real ones, but they should look to themselves before they throw stones, and ask who invented the imitation thatched roof of wooden shingles.

Shingle Roof

The wooden-shingle roof is of such old and traditional origin in this country that it seems useless to describe the essential features of its construction, yet for the sake of completeness we shall call attention to the important points to be observed. Cypress, cedar, and redwood are considered to be the best woods from which to saw shingles. The grain of the wood should be vertical and show the edge. It is generally conceded that creosote-dipped shingles which are treated at the factory are easier to apply than those dipped on the job, and, as all wood shingles should be treated with some preservative, it is well to consider them. However, much criticism has been aimed at factory-dipped shingles, in that they are generally too brittle from overdrying in the kilns, but this is not true of all makes. The sizes and the weathering of some of the standard creosoted shingles are as follows:

There are about thirty varieties of colored stains to select from, and special shapes are cut for constructing the so-called thatched roof, the shingles being bent to a curve of about 20 inches radius. The pitch of wooden-shingle roofs should not be less than 8 inches rise per foot for the ordinary weathering shown in the above statements. The tops of rafters are covered with shingle lath, with a spacing suitable to the weathering arrangement of the shingles. There are some who advocate the use of sheathing to cover the rafters in a tight manner and also the use of building-paper underneath the shingles, but, although this gives a tighter and warmer roof, dry rot attacks the shingle much quicker because of the accumulation of dampness on the under side of the shingle courses.

The first course of shingles at the eaves should be a double course with the upper layer breaking joints with the lower, and the shingles should project about 2 inches beyond the mouldings of the eaves and about 1½ inches beyond the edge of the gable ends of the roof.

Hips may be finished either with the saddle-board or with a row of shingles running parallel to the line of the ridge. Hips are best finished with a row of shingles running parallel with their edges, which treatment is called the Boston hip. If the courses are carried to the hip line and mitred, then the joint must be waterproofed by using tin shingles underneath the wooden ones, these tin shingles being folded over the hip. The method of flashing around chimneys, at the base of dormers, and in open valleys will be more fully discussed in connection with slate roofs, and, since the principles are the same, what is said for slate roofs in this connection is true for wooden-shingle roofs.

Method of Laying Roofs

SLATE

There has been much made of the so-called European method of laying slate roofs in recent years, but this type of roof costs more than the ordinary slate roof, since special heavy slate is used at the eaves, and the weathering is reduced as the courses approach the ridge, and special care is taken in blending colored slates. While this type of roof is very beautiful, it is really, from a point of view of cost, rather out of the race when applied to the small house, for it will be hard enough to stretch the estimates of the small house to include even the ordinary slate roof.

In the preparation of the ordinary slate roof, the rafters should be covered with ?-inch thick, tongued-and-grooved roofing-boards. In order to prevent buckling, if they should swell with dampness, it is essential not to drive the joints between boards up too tight. As these boards are surfaced only on one side, this side is laid against the rafters and the tongues are placed upward so that a better shedding of water is secured. Good nailing with tenpenny nails is important, and all joints at ends of boards should be made over rafters. A cheaper but not so good a bed for the slate can be made with common, unsurfaced sheathing-boards. In the cheapest kind of work sheathing-boards are not used, but only shingles lath.

Over the top of this rough boarding should be tacked 11 pounds per 100 square feet slater’s roofing felt, laid horizontally and lapping joints 3 inches.

The usual commercial sizes of slates are ³/16 inch thick, and of the following standard sizes: 6 by 12 inches, 7 by 12 inches, 8 by 12 inches, 7 by 14 inches, 8 by 14 inches, 10 by 14 inches, 8 by 16 inches, 9 by 16 inches, 10 by 16 inches, 12 by 16 inches, 9 by 18 inches, 10 by 18 inches, 12 by 18 inches, 10 by 20 inches, 12 by 20 inches, 11 by 22 inches, 12 by 22 inches, and 12 by 24 inches. They have two holes in each piece for nails, which nails should be 1-inch copper slater’s nails, or 3d galvanized slater’s nails for cheaper work.

The first course should be started 2 inches below the line of the sheathing-boards at the eaves, and the necessary tilt is given with a ³/16 by 1 inch cant strip. A double thickness of slate is used for the first course, the upper layer breaking joints with the lower. At the gable ends the slate should not overhang more than 1½ inches.

The exposure to the weather for courses of slate is determined by taking one-half of the length of the slate minus 3 inches.

The ridges of the roof may be finished in two ways, either with the combed ridge or the saddle ridge. The combed ridge is formed by projecting a finishing course and a combing course of slate on the north or east side of the roof 1½ inches beyond the top and combing course on the opposite side of the roof. Both courses are laid with slate set lengthwise, the length being twice the width of the slate used on the roof. This last course is laid in elastic roofing cement, and the nails are also covered with it.

The saddle ridge is formed by alternately butting the ends of the top course on one side with the top course on the other, and then doing the same with the combing course. This makes a zigzag joint which is closed by the elastic cement used in setting.

The Boston hip is the best. Each course is brought at its upper or nailing edge to within 2 inches of the hip line. A small strip of slate then finishes this off by fitting to a mitre cut made on a slate set parallel with the line of the hip. These hip slates have the lower corner of their butt ends on a line with the next lower course, and they are lapped with the opposite hip slate and made tight with roofing cement.

Hips may also be finished by bringing each course up to the hip line, and mitring them with the opposite courses on the other side of the hip.

Valleys should be lined with 16 ounces copper, 4 pounds lead, IX tin, or a prepared roofing roll weighing 37 pounds per 108 square feet. Measuring from the centre of the valley to the edge of the slate along the valley, this distance should be 2 inches at the top and increase ½ inch in every 8 feet length of valley, to widen it out toward the bottom. The flashing should extend up under the slate on either side about two-thirds the width of the slate used. If 8-inch by 16-inch slates are used, this means that the distance should be about 5 inches. If the slopes of the two intersecting roofs are different, and there is a chance that the volume of water sweeping down the larger and steeper incline may be forced up under the slate at the valleys, the metal lining should be crimped up (inverted V-shape) at the centre, 1 inch, to form a little dam against the rush of the flood.

Flashing used against chimneys, dormers, or other vertical walls should be bent up 4 inches and extend into the slate courses 4 inches. All vertical flashings against masonry should be cap-flashed and made tight with elastic cement. The cap-flashing should extend down over the flashing 3 inches, and be inserted into the masonry at least 2 inches.

Sometimes the closed valley is designed for slate roofs, in which case the valleys must be rounded out with the roofing-boards, blocked to position. The slate courses should be carried around this curved valley, but each course in the valley should be covered with flashing just under the lap of the course above and extend up toward the nails.

TILE ROOFING

Preparations of the roof for the laying of tile should follow similar lines described for slate roofs. Over the roofing-boards should be tacked asphalt roofing felt, weighing not less than 30 pounds per 100 square feet and lapping 2½ inches.

The valleys should be lined with this felt, running the entire length, and then the flashing metal placed on top, secured with clips at intervals. The width of the valley metal should not be less than 24 inches, and both edges should be turned up ¼ inch the entire length of the strip. The felt covering the main surface of the roof should lap over the valley metal 4 inches.

Cant strips must be nailed along the eaves to start the first course of tile, unless special tiles are provided. Copper nails should be used to fasten these tiles, and each unit should be locked with the next, as the pattern demands.

Tiles which border the hips should be cut close against the hip board, and elastic cement used to make the joint tight. All hips and ridges are finished with specially designed ridge and hip roll tiles, and the interior spaces should be left empty and not be filled with pointing mortar as is sometimes done.

ASBESTOS SHINGLES

Asbestos shingles are applied in practically the same way as slate. Over the roofing-boards should be laid slater’s felt as for a slate roof, and a cant strip ¼ by 1½ inches should be nailed along the eaves line to start the first course of asbestos shingles, which should be a double course and overhang the eaves 1½ inches. The average size of asbestos shingles is 9 by 18 inches by ¼ inch for the lower layer of the first course, and 8 by 16 inches by ? inch for the upper layer of the first course and the other courses. They are laid about 7 inches to the weather, and the ridges and hips may be finished with the Boston hip, or by a specially designed ridge and hip roll. Where the hip roll is used the ridge-pole should project above the roof, or a false one be added so that a substantial nailing can be had for this tile.

The most widely advertised asbestos shingle roofs employ shingles which have rough edges, and which have various shades of coloring, some gray, some red, others reddish brown, and others grayish brown. The causes which led to the development of this type of roof were the artistic failures of the first asbestos shingle roofs. These early roofs were made with shingles which had edges as smooth and sharp as steel plates, surface texture as slick as a trowelled cement floor, and colors of either gray or pale red that were so perfectly matched that at a distance the individual shingles blended into one dead-level plane, so that the roof of the house looked more like the armored plate of a battleship than anything else—it was so perfectly made.

ASPHALT SHINGLES

Before laying asphalt shingles the rafters should be covered with tongued and grooved roofing-boards, and these covered with black waterproof building-paper, lapped 2 inches.

There are two types of asphalt shingle units. One consists of a unit of twin shingles, so arranged that the butt ends which show to the weather appear as two individual shingles, and the other consists of one shingle unit. Both types are usually laid 4 inches to the weather and nailed with 1-inch galvanized nails No. 10 wire with ?-inch heads. At the eaves should be nailed a galvanized-metal drip edge, and over this a double course of shingles for the first course. Hips and ridges are finished with what appears to be a Boston hip, but the shingles are bent over the hip line. The valleys and gutters are best when they are lined with strips of ready roofing similar to the shingles themselves.

Asphalt shingles which come in long rolls or units of four or five are laid in a similar manner, except that, due to their continuous length, they are unable to expand without bulging up on the roof.

TIN ROOFS

Flat roofs, with an incline of about ½ inch to the foot, should be covered with the flat-seam roof. The standing seam may be used on roofs with a pitch not less than 2 inches to the foot. The tin is laid upon the sheathing-boards without an intermediate layer of building-paper; in fact, tar paper should never be used. In cities building codes often require that tin roofs should be laid upon roofing felt ¹/16 inch thick, placed over the sheathing-boards, but this is a fire precaution against burning brands which may drop upon the roof, for this felt cushion gives an air insulation, preventing the quick ignition of the decking below the tin.

In laying the flat-seam roof a number of sheets are fastened together to form a long strip of tin. The edges are bent over ½ inch, so that they can be interlocked with the next strip. The tin is fastened to the roof with tin cleats that lock into the seams of the sheets and are fastened at the other end with two 1-inch barbed-wire nails. These cleats are spaced about 8 inches apart. All the seams are flattened down, and solder well sweated into them, rosin being the only flux used.

Tin, approximately in thickness 30-gauge, U. S. Standard, is called IC, and recommended for the roof proper, while valleys and gutters should be lined with IX tin, approximately 27-gauge. It should be painted on both sides, before laying, with pure linseed-oil and red lead, or red oxide, Venetian red, or metallic brown. Two coats should be given to the exposed side and a third coat about a year later. Before the second coat is applied the first should have dried for at least two weeks.

The construction of the standing seam roof is shown in the drawings to consist of long strips of tin, made of standard sheets fastened together with the flat and soldered seam, but the edges of the strips fastened to the next strip with the so-called standing seam, which must run parallel to the pitch of the roof. Cleats, spaced a foot apart, are used to fasten the tin to the sheathing-boards. One edge of the next strip is turned up 1½ inches, and then over the top of the edge of the other strip. The cleat is locked in between the two. The upstanding seam is then turned down again upon itself, tightly locking the strips together.

Copper and Zinc Roofs

For a while, during the high prices created by the war, the thought of building a copper roof or a zinc roof on the small house would have been received with a doubtful shake of the head. This is no longer the case, however, for the prices of these materials have come down to within reason, and there is no doubt as to their durability. No one has questioned the weathering qualities of copper or zinc. The copper roofs which have shown such practical durability on large buildings have usually been laid about the same as that described for standing seam tin roofs. Cold-rolled or soft copper sheets, usually 20 inches wide, are used for this roof covering, weighing not less than 16 ounces to the square foot.

This type of roof is rather expensive for the small house, even with the reduced cost of copper, and for this reason a lighter grade has been made, and offered for use in the form of pressed-metal shingles of very flat design. These copper shingles have been treated so that other colors than the copper shades can be secured.

The zinc manufacturers have also placed on the market zinc shingles of special interlocking flat design for use on small houses.

It has always been a debated question as to whether pressed-metal shingles were architecturally permissible. Certainly there are some forms which imitate the clay tile shingle that are decidedly inartistic, but the more natural flat patterns are less subject to this criticism.