House Construction/Structural building
Structural building
[edit | edit source]Rough Framing
[edit | edit source]The Framing begins with the anchoring of the studs to the concrete foundation. Walls are constructed of Wood Studs typical 16" on center - framing studs come in 2 x 4, 2 x 6, 2 x 8, 2 x10 and lengths of 6,8,10,12 feet and longer. Floor/Ceiling joists are typically an engineered lumber product, as are the Roof Trusses, both ordered to size. Sheer Walls are constructed by sheathing the stud walls with plywood on one or both sides - used primarily in earthquake regions. Exterior walls are sheathed with plywood or oriented strand board and usually a Owens Corning Rigid Insulation Product.
Masonry
[edit | edit source]Masonry structures are those built of stone, or of stone-like (petrous) materials, leading to confusion since at times this activity is also referred to as Stone Masonry. The enduring character of masonry structures, the relative simplicity of the processes involved, the pleasing outlines usually obtained, together with the almost universal availability of the materials and the consequent moderate cost, render masonry construction one of the most important of the builder's activities. It is often used in creating the building foundations, walls, linings.
Footing courses
[edit | edit source]Footing courses are the bottom courses in masonry; they are generally built to extend beyond the face of the wall and to cover a greater area than the base of the regular wall. Footing courses distribute the weight of a structure over a great area, thus diminishing liability of settlement and increasing stability. Always use the largest stones in the footing courses; they should be laid upon their natural beds and well bonded into the wall so as to avoid the possibility of shearing off that portion of the footing course which projects beyond the face of the wall; also care should be observed, to keep all joints in this projecting portion of the footing courses, especially in brickwork, as far as possible back of face of wall. Stones used in footing courses should be at least eight inches thick and two or three feet on other dimensions. Footing courses should extend, at the bottom, at least twelve inches beyond the face of the wall.
Lime mortar
[edit | edit source]Usage: sticking stone and brick together
Fat limes (that is, limes which are pure, as opposed to hydraulic, water transferring limes which are burnt from limestone containing some clay) should not be used for mortar; they are slow-setting, and there is a liability for some of the mortar, where there is not a free access of air to assist the setting, remaining soft for some considerable period, often months, thus causing unequal settlement and possibly failure. Grey stone lime is feebly hydraulic, and makes a good mortar for ordinary work. It however, decays under the influence of the weather. It should never be used in foundation work, or where exposed to wet. Lias lime is hydraulic, that is, it will set firm under water. It should be used in all good class work.
Ordinary lime mortar may have its strength considerably enhanced by the addition of a small proportion of Portland cement.
Roman cement is rarely used for mortar, but is useful in some cases on account of the rapidity with which it sets, usually becoming hard about fifteen minutes after mixing. It is useful in tidal work and embankments, and constructions under water. It has about one-third of the strength of Portland cement, by which it is now almost entirely supplanted.
Selenitic cement or lime, invented by Major-General H. V. D. Scott (1822-1883), is lias lime, to which a small proportion of plaster of Paris has been added with the object of suppressing the action of slaking and inducing quicker setting. If carefully mixed in accordance with the instructions issued by the manufacturers, it will take a much larger proportion of sand than ordinary lime.
Lime should be slaked before being made into mortar. The lime is measured out, deposited in a heap on a wooden " bank " or platform, and after being well watered is covered with the correct proportion of sand. This retains the heat and moisture necessary to thorough slaking; the time required for this operation depends on the variety of the lime, but usually it is from a few hours to one and a half days. If the mixing is to be done by hand the materials must be screened to remove any unslaked lumps of lime. The occurrence of these may be prevented by grinding the lime shortly before use. The mass should then be well "larried", i.e. mixed together with the aid of a long-handled rake called the "tarry." Lime mortar should be tempered for at least two days, roughly covered up with sacks or other material. Before being used it must be again turned over and well mixed together.
Roman cement mortars must be mixed as required on account of its quick-setting properties. Fresh Roman cement mixtures must be made several times a day, as near as possible to the place of using.
Cement mortars should never be worked up after setting has taken place. Care should be taken to obtain the proper consistency, which is a stiff paste. If the mortar be too thick, extra labor is involved in its use, and much time wasted. If it be so thin as to run easily from the trowel, a longer time is taken in setting, and the wall is liable to settle; also there is danger that the lime or cement will be killed by the excess of water, or at least have its binding power affected.
It is not advisable to carry out work when the temperature is below freezing point, but in urgent cases bricklaying may be successfully done by using unslaked lime mortar. The mortar must be prepared in small quantities immediately before being used, so that binding action takes place before it cools. When the wall is left at night time the top course should be covered up to prevent the penetration of rain into the work, which would then be destroyed by the action of frost. Bricks used during frosty weather should be quite dry, and those that have been exposed to rain or frost should never be employed. It is generally agreed, that from a practical point of view, bricklaying should not be carried on at temperatures lower than 14° to 9° F, for as the thermometer falls the expense of building is greatly increased, owing to a larger proportion of lime being required.
For grey lime mortar the usual proportion is one part of lime to two or three parts of sand; lias lime mortar is mixed in similar proportions, except for work below ground, when equal quantities of lime and sand should be used. Portland cement mortar is usually in the proportions of one to three, or five, of sand ; good results arc obtained with lime mortar fortified with cement as follows:—one part slaked lime, one part Portland cement, and seven parts sand. Roman cement mortar should consist of one or one and a half parts of cement to one part of sand. Selenitic lime mortar is usually in the proportions of one to four or five, and must be mixed in a particular manner, the lime being first pround in water in the mortar-mill, and the sand gradually added. Blue or black mortar contains equal parts of foundry ashes and lime; but is improved by the addition of a proportion of cement. For setting fire-bricks fire-clay is always used. Pargetting for rendering inside chimney flues is made of one part of lime with three parts of cow dung free from straw or litter. No efficient substitute has been found for this mixture, which should be used fresh. A mortar that has found approval for tall chimney shafts is composed by grinding in a mortar-mill one part of blue lias lime with one part each of sand and foundry ashes. I n the external walls of the Albert Hall the mortar used was one part Portland cement, one part grey Burham lime and six parts pit sand. The lime was slaked twenty-four hours, and after being mixed with the sand for ten minutes the cement was added and the whole ground for one minute; the stuff was prepared in quantities only sufficient for immediate use. The by-laws dated 1891, made by the London County Council under section 16 of the Metropolis Management and Building Acts Amendment Act 18781 require the proportions of lime mortar to be one to three of sand or grit, and for cement mortar one to four. Clean soft water only should be used for the purpose of making mortar.
Portland cement
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Bricks
[edit | edit source]Adobe, clay and straw bricks - hand-formed
[edit | edit source]Adobe, ado' bee, a word of Spanish origin, applies to unburnt, sun-dried bricks used in the arid regions of Mexico and the Southwest United States, and also to the peculiar clayey soil from which they are made. When moist, the soil is very plastic and can be molded into any shape, but when dry, adobe is almost unbreakable. This characteristic was recognized by the aborigines at an early date, and they not only made bowls, pitchers and other vessels from it, but shaped the muddy clay into bricks, which they laid out to dry in the sun. Adobe houses are common in Mexico and Arizona, even to-day. As they are cheap and easy to construct, they are used chiefly by the Mexicans and Indians, but many white people, who could afford other building material, prefer them because they are always cool, even in the hottest weather.
The process of making adobe bricks is simple. The wet adobe is shaped into bricks of various sizes, which are then baked by exposing them to the sun for ten days or two weeks. During this time they are turned every day. Bricks made in the same way were used by the ancient Egyptians and Babylonians, and were made by the children of Israel during their enslavement in Egypt.
The art of making bricks dates from very early times, and was practiced by all the civilized nations of antiquity. Brick-making formed the chief occupation of the Israelites during their bondage in Egypt, but in this case the bricks were probably sun-dried only. These bricks were made of a mixture of clay and chopped straw or reeds, worked into a stiff paste with water. The clay was the river mud from the banks of the Nile, and as this had not sufficient cohesion in itself, the chopped straw (or reeds) was added as a binding material. The addition of such substances increases the plasticity of wet clay, especially if the mixture is allowed to stand for some days before use; so that the action of the chopped straw was twofold; a fact possibly known to the Egyptians. These sun-dried bricks, or "adobes", are still made, as of old, on the banks of the Nile by the following method — a shallow pit or bed is prepared, into which are thrown the mud, chopped straw, and water in suitable proportions, and the whole mass is tramped on until it is thoroughly mixed and of the proper consistence. This mixture is removed in lumps and shaped into bricks, in molds or by hand, the bricks being simply sun-dried.
Brick veneer on wood frame walls
[edit | edit source]When applied over wood frame walls, a weather-resistive-barrier is critical to protect the wood framing from water damage. Masonry is not waterproof.
Roof
[edit | edit source]Mansard, Shed, Hip, Gamble, Saltbox and Gable can be covered in Asphalt and Wood Shingle, Terracotta Tiles, Slate Tiles, Copper Sheeting and Metal Standing Seam the most common roofing materials.
Based on geometry roofs can be classified as sloped, pitched or flat. The "pitch" of the roof is dependent on geographic location - Higher pitched roofs are typically found in cold climates but also in wet climates.
Straw and thatch
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Rain Control
[edit | edit source]Depending on the architectural style the Gutter, Downspouts and Collector Box's may be exposed or built with the roofs eaves and walls.