Part 5

The ideal form of a fireplace would be a cone with all sides tapering to the apex for the escape of smoke. Therefore, to approach this ideal in practice, the sides of the fireplace are splayed and the back curved forward as shown in Figs. 36 and 37. This forward curve of the back throws the smoke from the fire forward to a throat 4 inches wide, extending the full width of the opening at the front and top of the fireplace, and at the same time forms a shelf above for the deflection of down drafts in the chimney. The rear wall of the fireplace should never be straight, having the throat at the rear, as down drafts would be sure to blow smoke and dust into the room.

[Sidenote: The Damper]

Always place a damper in the throat for regulation of the draft. The damper should completely fill the throat. There are many dampers on the market that also serve the purpose of a lintel for the brickwork, giving a smooth surface for the exit of the smoke. These patent combinations of damper and throat give a good draft, prevent smoke, and deserve a more general use.

Especial care should be taken in laying up the brickwork above and around the damper. The joints should be well filled, and nowhere should there be less than an 8-inch thickness of brickwork unless protected by the flue lining.

[Sidenote: The Flue]

Immediately above the damper, the brickwork should be corbeled in both ways to the size of the flue lining, which should always be started on a line with the middle of the fireplace and run vertically for one length. It then may be jogged over to the location desired on the floor above. It should be started as low as possible as this is the hottest part of the chimney.

The back and sides of the fireplace, as well as the back portion of the hearth are usually built of fire brick. Certain kinds of face brick are suitable for this purpose and have been used by architects with very artistic results.

[Sidenote: The Hearth]

The hearth may be either of face brick or tile. If of brick, they should be preferably smooth so as to facilitate cleaning. They may be laid either on edge or flat in a variety of patterns. Two examples of brick hearths are shown in Figs. 38 and 39, one with the brick set on edge and the other with the brick laid flat. Tiles may be of any size and laid in various patterns, and if suitable, may be used also in the back portion of small hearths. The mortar joints of the hearth should be thin and preferably of a fire clay mortar, though pure cement mortar will answer the purpose. Wherever possible, an opening and ash chute in the back hearth, with a pit and iron cleanout door in the basement, should be installed.

Always build the fireplace in the rough first, leaving the brick facing and hearth to be finished after the plasterer has completed his work. The accompanying designs, A, B, and C, suggest various methods of treatment.

Outside Ornamental Features

The possibilities of the use of brick for floors, walks, steps, pergolas, gate posts, seats, and other places about the house and garden are unlimited. For outside work it is a most permanent and beautiful material which never cracks or decays requiring periodic repairs or painting such as other materials do. It may always be the same color and texture as the brickwork of the house, thereby linking the house and garden together into one harmonious whole.

[Sidenote: Steps]

Brick steps, except where supported by the foundation wall, as shown in our working drawings, should always be laid over a concrete slab, reinforced, unless resting on solid, undisturbed soil. The concrete slab is poured in the form of steps, to correspond to the finished brick steps, but with proper allowance for laying the brick flat or on edge in a cushion of sand, at the option of the owner. Figs. 40-42 illustrate different pitches of steps and methods of setting the brick. Great care should be taken in the laying of brick steps, if they have to withstand severe usage. The joints should all be filled with a rich cement mortar composed of one part cement to two parts sand.

[Sidenote: Walks and Floors]

Brick walks and floors, with the brick on edge or flat, are usually laid on a filling of cinders or sand, but if subjected to hard use, they should be placed on a bed of concrete the same as steps. Two favorite patterns of edge set brick are shown in Figs. 55 and 56. The brick may be laid flat in the same patterns, but the effect is not quite so pleasing. The joints in the brick walk or floor are usually filled with sand, swept into place with a broom so as thoroughly to fill the joints, but they may be filled with cement grouting if desired. The thin grouting is carefully poured into the joints after the brick are laid, and all grouting that spills on the surface of the brick cleaned off before it hardens. The borders of the walk or floor may be made of brick set on edge or on end; or, if preferred, of concrete, especially when the walk or floor is placed on concrete. If it is desired to prevent grass and moss from growing in sanded joints, mix salt with the sand before filling the joints.

[Sidenote: Pergolas]

For pergola posts, brick imparts a feeling of strength and solidity, yet care must be taken not to make the posts too large, as they will be entirely out of fit proportion to the light wooden rafters and vines which they support. In most cases, a post 12 inches square will be about the right size. Foundations for these posts should always extend below the frost line and be of brick or concrete. A long, one half inch steel rod with nuts and large washers at each end should be imbedded about 18 inches in this foundation and extend beyond the top of the finished post. The brickwork of the post above grade should be one brick thick, laid in cement or cement-lime mortar giving a hollow space 4 inches square in the center of the 12-inch post. As the work progresses this space is filled with concrete around the rod, which, passing through the center, binds the brickwork together in a solid, reinforced mass (Fig. 43). The cap of the post may be either brick, stone, or concrete placed when filling the interior. The wooden girders of the pergola may now be bolted to the post by means of the bolt projecting above the top.

If conditions or design demand a heavier post than 12 inches square, as in Fig. 44, no steel rod reinforcing will be necessary for stability.

[Sidenote: Gate posts]

Gate posts are usually lower and heavier than pergola posts and made stable enough to carry whatever weight the iron or wooden gate may demand. Large driveway gates (Fig. 45) should have a steel I-beam or angle placed in the center of the post and extending from the bottom of the foundation to the top of the post. The anchors for the support of the gates should be riveted to this steel beam or angle so that no undue strain will be exerted on the brickwork. The brickwork should always be laid in cement or cement-lime mortar. If ornamental caps are desired, they should be of stone or concrete. On large posts, it is desirable to lay brickwork in some natural bond as this not only increases the rigidity of the post but gives a beautiful effect.

[Sidenote: Garden Walls]

Long, straight garden walls under 4 feet in height may be built 8 inches thick; over 4 feet high they should be 12 inches thick. If the walls are snort or reinforced at intervals with buttresses they may be only 8 inches thick provided they are not carried up over 6 feet. A footing is not needed but the foundation of common brick should extend below frost line. The wall should be finished on both sides with face brick, laid with cement-lime mortar in a natural bond, and should have a brick rowlock coping laid in rich cement mortar. Fig. 45 gives an idea of a garden wall with soldier base and rowlock coping.

BRICK BONDS

Bond in brickwork is the overlapping of the brick one upon the other, either along the length of the wall or through its thickness, in order to bind them together into a secure structural mass. It is true, mortar is used to cement the brick together into a monolithic whole, but the real bond is the overlapping of the brick which the mortar serves to maintain. Units are shifted back and forth so that the vertical joints in two successive layers or "courses" do not come into line; in other words, the brick are laid so as to break joint, the whole forming a natural bond or a structural unity giving strength to the wall.

The strength and rigidity of a wall due to this bonding are clearly shown in Fig. 46. A concentrated load at any point on the wall is thus distributed over a larger area as indicated by the dotted arrows.

[Sidenote: Stretcher and Header]

In speaking of brick bond, two terms are constantly recurring, viz., "stretcher" and "header." When a brick is laid lengthwise of the wall, thus showing its long, narrow dimension or "face" on the surface, it is called a stretcher. If its length extends back into the wall, so that its short dimension shows on the surface, it is called a header. The stretcher secures strength in the length of the wall. The header serves to form the transverse bond, that is, the strength of the wall through its thickness. When a brick is broken, as the case may require, the fragment is called a "bat." Bats are used either simply to fill in; or, as definite sized pieces, cut and used to make the bond come out right, in which case they are called "closures." While at certain points of the wall bats may be necessary, they should be sparingly used and then only according to the best practices of the craft.

[Sidenote: Design in Bonds]

In the old days, and indeed up to comparatively recent times, brick bond was used only in a structural or natural way, that is, to secure the strength of the wall as a solid mass; but in the seventeenth century European builders began to see an artistic possibility in the bond as it appeared on the surface. They began to see the fine tracery of the mortar joint running over the background of the brick, which could be varied into attractive patterns by different arrangement of the brick bond. As a consequence, there have been developed, in the main, three different types of bond, Running or Stretcher, English, and Flemish, which are used at the present day, with various modifications, to secure attractive effects in pattern.

When, as compared with the past, the great variety of brick colors and textures now offered is taken into consideration, it may be realized what charming results may be secured in the wall surface by the combination of brick patterns, colors, textures, and mortar joints.

[Sidenote: Running]

The first and most obvious of these bonds is what is called Running or Stretcher Bond. The wall surface is made up of stretcher courses having at the corners a header which appears as a stretcher on the return side. This bond has the merit of being very strong longitudinally, but lacks transverse strength; consequently, it is modified into what is called Common or American Bond by laying a course of headers about every sixth course (Fig. 47). In order to maintain the effect of the running bond, a special double header bond is sometimes used as explained on page 19.

This method of using headers as in Common or American Bond, in order to secure transverse strength of wall, can be treated in a way to produce very much more pleasing effects, as may be seen in the English and Flemish Bonds.

[Sidenote: English or Dutch]

The English Bond is made up of alternating courses of stretchers and headers (Fig. 48). This produces a very pleasing series of Greek crosses and ripple lines up and down the surface of the wall, and the English brickbuilders claim for it the great merit of giving transverse strength to the wall. It however has a certain monotony that has lead to a modification which greatly beautifies it as a pattern, by breaking the joints of the successive stretcher courses (Fig. 49). This is called English Cross or Dutch Bond and results in a very attractive pattern in the wall of Greek crosses running in diagonal lines. The Dutch Bond differs from the English Bond only in the way the corners of the wall are treated.

[Sidenote: Flemish]

The Flemish Bond (Fig. 50) secures its effect by laying each course in alternate stretchers and headers, the header resting upon the facile of the stretcher in successive courses. This produces a very attractive pattern of inlaid Greek crosses and is a favorite among builders because of its artistic effect. It also may be modified in various ways by shifting the stretcher or header so as to produce different pattern effects, thus the Garden Wall Bond so-called (Fig. 51), is made by laying the courses with from two to four stretchers alternating with a header.

Figs. 47-51, illustrating the above bonds, are all drawn to show both exterior and interior corners of a wall, which is drawn as a two-brick wall at the left end and a three-brick wall at the right. The inside face of the three-brick wall in all cases is bonded to the middle tier by Common Bond. The method of starting the bond at the corner is clearly shown, whether by a quarter, half, three-quarter, or whole brick, also how the brick are cut or clipped, and how closures are used.

[Sidenote: Face Brick Patterns]

With these three fundamental bonds--the Running or Stretcher, the English, and the Flemish, innumerable other patterns may be made by the simple device of shifting the stretcher or header in successive courses back and forth, always breaking the joint, that is, never permitting two successive vertical joints to lie in the same line. To illustrate, we give examples of diamond-shaped patterns in Figs. 52 and 53 which are secured by a modification of the Garden Wall Bond. It is, however, only in case of large wall surfaces that patterns of an elaborate character could be recommended; ordinarily, the three bonds mentioned, with their simple modifications, will cover all requirements of domestic architecture. Simple patterns in brickwork may be made very attractive. Any departure from simple bonds adds to the cost of the bricklaying.

In addition to bonds proper and the patterns that may be woven out of them, there are certain other pleasing ornamental effects that may be secured in the wall surface by the arrangement of the brick. Thus for a water table or a sill course, the header or the stretcher may be set vertically. Treated in this way headers are called "row-locks" and stretchers, "soldiers" (see Figs. 44 and 45). For dadoes and friezes or for paneling, especially on large surfaces, patterns of a simple or ornate design may be used, as in Figs. 52-56.

MORTAR JOINTS

[Sidenote: Great Importance]

In examining the bond in a brick wall, the eye naturally is first attracted to the brick units as so many colored spots arranged in different order so as to produce a certain pattern effect; but this pattern effect in the brickwork depends very largely upon what at first may be overlooked or disregarded, the mortar joint. The mention of mortar suggests in the mind a very commonplace thing which the workman mixes and carries in a hod to the bricklayer; but it is concave one of the most important elements entering into the beauty, as well as the strength, of a brick wall.

[Sidenote: Effect of Mortar Color]

When you consider that all the joints in brickwork, both vertical or "head" joints, and horizontal or "bed" joints, are filled with mortar weathered of one color or another, amounting on an average to one-seventh of the wall, it is evident what a vital part they play in the appearance of the entire wall surface. An artist will tell you that this amount of color introduced into any surface will greatly modify, by contrast or analogy, the general effect, so that it is of the utmost importance, in selecting the sort of brick you wish for your wall surface, that you also select the mortar joint.

[Sidenote: Three Elements Involved]

Three elements must be carefully considered in dealing with the mortar joint: its color, its texture, and its size and kind. The color of the mortar joint may be such as entirely to destroy the beauty of the brick. On the other hand, if it is properly chosen, it will bring out the fine shades and tones of the brick in such a way as to enhance very greatly its natural beauty. Then, the mortar joint has a certain texture which is produced either by finishing it rough or smoothing it with the trowel or a tool made for that purpose. This mere treatment of the surface of the mortar joint has more to do with the appearance of the wall than one might at first suppose. In addition to that, the size of the mortar joint, running from a thin "buttered" joint up to an inch in width affects the color relation of the whole surface; and the kind of joint, whether cut flush, raked out, or tooled in various shapes, has a distinct bearing on the whole effect (Fig. 57). In a word, do not neglect the mortar joint, for it is one of the most important elements that go to make up the beautiful fabric of the brick wall, in the building of which there is deserved and required the exercise of a fine discriminating taste.

All in all, what with the convenient units of stretcher and header, each with its color and texture, you have a medium in the choice of bond, mortar joint, and pattern for weaving the most charming mosaic or tapestry effects into the wall surface, a possibility offered by no other material than face brick.

Mortar Colors

Colored mortar joints may be produced in two ways, first, by the use of a natural colored sand or ground granite or other stone, and secondly, by the use of artificial mortar colors. Pure white joints are obtained by using white sand or ground limestone or marble. As the color of the mortar greatly affects the appearance of the finished wall, much care should be given to the selection and proper use of these colors, whether natural or artificial. As the color of the finished mortar after it has set and dried is never the same as that of the fresh mortar, experience is the only guide for the proper preparation of the mortar. Someone has well said that the right way to make mortar is to mix brains with it.

When artificial color is used, it should first be thoroughly mixed with the dry sand. Never add this mixture to hot lime. But after the slaked lime has thoroughly cooled, mix it with the colored sand in batches in a separate box. If preferred, the color may be made into a thick paste with water and then added directly to the mortar. In either case, thorough mixing and uniform proportion of quantities are essential. The more thorough the mixing and uniform the proportions, the more permanent and uniform will be the color and the less color required. Use the best colors obtainable on the market, as cheap colors may ruin the appearance of the wall.

[Sidenote: Quantities]

As to quantity required, the exact amount of color varies greatly with the exact shade of the color selected, the width of the mortar joint, and the brand used. As a fair general estimate, it will take approximately 75 pounds of coloring matter for every 1000 bricks laid with 3/8 to 1/2-inch mortar joints. But it is always safest to follow the directions of the manufacturer as to the kind of color and the exact amount required.

Various Kinds of Mortar

[Sidenote: Materials]

Mortar, as the bonding material between brick, must be given careful attention as the strength of the wall depends on its quality. Mortar is composed of sand and either lime or cement, or both. In all cases the materials should be the best. The cement should pass the test of the American Society for Testing Materials. The lime should be either fresh and well-burned lump lime, slaked so as to produce a smooth, puttylike mass without lumps, or the prepared hydrated kind found on the market. The sand should be sharp, clean, and free from foreign matter, and screened through a mesh of the size to secure the proper fineness. For wide joints, the mortar needs, instead of sand, fine gravel of the size required to give it sufficient body.

[Sidenote: Kinds of Mortar]

In large cities the building ordinances require certain mixtures of mortar. For various mixtures see page 104. But where there are no legal requirements, the contractor's own judgment and experience should guide him in the selection of the proper mix, as each one has certain qualities which recommend it. Portland cement mortar is stiffer and harder to work than lime mortar, but should always be used where permanence and strength are required, as in exposed or heavy bearing situations, or in cold weather when the mortar must set before it freezes. Lime mortar may do for the usual work, above the grade in dry warm climates. It should not, however, be used for basement walls, except possibly where the soil is extremely dry, nor for piers or points in the wall that carry heavy loads. It is smooth and works easily, so that more brick can be laid per day than with cement mortar, but its use should be limited to the proper situations. Cement-lime mortar has the combined qualities of both cement mortar and lime mortar. It has both strength and good working qualities, and costs less than cement mortar. It is preferred by many to cement mortar; we recommend its use in proper situations, throughout this Manual.

[Sidenote: Mixing Cement Mortar]

Cement mortar must be mixed and used immediately, as cement sets very quickly. On this account, it should not be made in large quantities and, once it has obtained a partial set, should never be re-tempered. The cement and sand for cement mortar should be thoroughly mixed while dry, by turning the material over three or four times with a shovel, when sufficient water to make a plastic mass should be added, turning again several times. It is always desirable to add a small quantity of lime, when tempering the cement mortar, in order to make it easier to work.

[Sidenote: Mixing Lime Mortar]

Lump lime should be slaked as soon as possible after delivery on the job. If it is allowed to stand for any length of time, it should be stored in an air-tight box; otherwise, it may become air slaked, reducing mostly to powder and soft, crumbly lumps. The fresh lime is always in hard lumps and should be free from cinders. Lime is slaked in a mortar box by adding water to the lump lime. On adding water the lime becomes very hot, gives off vapor, and finally burst into a powder which gradually reduces to a paste known as lime putty. The exact amount of water necessary varies with different limes, but in all cases, the right proportions used in slaking must be watched carefully. An excess of water will stop the slaking process. If not enough water is used the lime will "burn" and lose its strength. If left overnight, the mortar box should be covered with planks.