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Building Materials

Myriad building materials goes into a house. and each type of material—from wood to steel—can be produced with a variety of characteristics and qualities. Choosing the proper material for a particular purpose and then picking the most desirable grade of that material are extremely important factors in good house construction.

WOOD

General Information and Properties

Wood is the basic material that most houses in this country have been made of in the past, are being made of today and apparently will be made of in the foreseeable future. Fortunately, because of wise forest- management programs, more timber is being grown each year than is being cut down and lost through natural causes. Certain species, however, are being depleted faster than they are being replaced and conservation work still is needed.

.Wood is a popular house building material because of its universal availability, low price, high compression and tension strength, resistance to bending and resistance to impact. It can be easily worked with simple tools and is highly durable, as evidenced by the many 300-year-old houses still standing today. It also has excellent insulating qualities and its natural grain is very decorative and appealing. Four basic building materials are made from raw wood: lumber, plywood, laminated timber and fiber board.

Wood is divided into two classes: softwood and hardwood. This division is based on a botanical difference and not necessarily on the actual hardness or softness of the wood. Softwood comes from coniferous (cone-bearing) trees, most of which have needles rather than leaves. It is used for framing lumber, sheathing boards, roofing, subflooring, siding, some flooring, some molding and some paneling. Hardwood comes from deciduous (leaf-shedding) trees with broad leaves. It is used for hardwood floors, some interior paneling, cabinets, furniture and some molding.

Lumber

After a log is felled, it's sawed or planed into various sizes and shapes called lumber. Lumber is divided into the broad classifications of boards (1 to 1½ inches thick, 2 inches and wider), timbers (5 inches and thicker and 5 inches and wider) and specialty products (various sizes). The majority of lumber used in residential construction is 2 inches thick or less. See Figures 7.1 and 7.2.


FIGURE 7.1 Raw Wood


FIGURE 7.2 Typical Types of Worked Lumber

Plywood

Softwood plywood is used extensively in house construction. The most common size sheet is 4 by 8 feet, but lengths up to 16 feet or longer and widths up to 10 feet also are available. The number of plies always is odd and the minimum number is three, which, together, run from 1/8 of an inch (special use only) to 3/8 of an inch thick; five plies run from 1/2 to 3/4 of an inch thick and seven plies run from 7/8 of an inch to 1 1/8 inches thick.

Two types of softwood plywood are available. The exterior type is used whenever the wood will be used where it will get wet, such as for fences, sheathing and siding. It is glued with adhesives that are insoluble in water. Interior plywood is made with less-expensive water-soluble adhesives; therefore, it must not be used where it will be exposed to water or high humidity.

Softwood plywood is graded by appearance. Poor appearance is caused by defects in the face sheets of veneer. The range of grades is: “N” grade used only for special work; “A” grade, good for the majority of ex posed painted surfaces; “B” grade (in which defects have been repaired), good for concrete forms where a smooth surface, but not appearance, is important; “C” grade, which contains light unrepaired knots and often is used for sheathing; “D” grade (with larger knotholes and defects), which is unsuitable for most house construction.

There also are three additional softwood plywood grades called engineered grades. Standard grade is designed for use as floor, wall and roof sheathing. Structural I and II grades are unsanded and made with water proof adhesives and are used in making stressed-skin panels, box beams and trusses.

Hardwood plywood is used as a decorative material for wall paneling, doors and block flooring. It takes its name from whatever species is used for the face veneer, i.e., mahogany plywood, maple plywood, etc.

Another major difference in the manufacture of softwood and hard wood plywood is the use of a solid “core” or extra-thick middle ply in many hardwood panels. Lumber-core plywood contains a core made up of narrow strips of solid wood. It often is used for cabinets and doors.

Particleboard-core plywood contains a core made of wood particles bonded together with a resin binder. It has great dimensional stability and is good for tabletops and countertops. Mineral-core plywood is used for fire-resistant panel construction. Veneers are bound to a core of hard, noncombustible material.

The most common size of hardwood panel is 4 by 8 feet, but, like softwood plywood lumber, larger sizes are available on special order. The number of plies always is odd and the minimum number is three, which, together, run from 1/8 to 3/4 of an inch thick; five plies from 1/4 to 3/8 of an inch thick, seven plies from 1/8 to 3/4 of an inch thick and nine plies from 3/4 of an inch to 1 inch thick.

There are four types of plywood available, depending on the kind of adhesive used. Type I is made with a waterproof adhesive for use where the plywood will come in contact with water; type II is made with a water-resistant adhesive for use in areas of high humidity and dampness and type III is made with a moisture-resistant adhesive for use in areas with some humidity. The technical grade (type IV) is a special product that provides equal stiffness in both directions.

Hardwood also is graded to indicate the quality of the face veneer. The grades in order of descending quality are: Premium, Good grade (#2), Utility grade (#3), Backing grade (#4) and Specialty grade (SP). Hardwood panels primarily are used for their decorative quality. Their appearance is affected by tree species (any of almost 250 different species are used to make hardwood plywood). The part of the tree the wood is cut from affects the look of the grain, as does the method of cutting. Finally, the manner in which the pieces of veneer are applied and matched produces still more variation in the appearance.

A multitude of special manufacturing processes and treatments make possible an almost unlimited variety of plywood finishes and characteristics (see Figure 7.3). Many manufacturers, in addition to making the standard panels, also make a line of their own special panels. Some of the common things manufacturers do to alter the appearance are to groove the surface, striate it, brush it or emboss it.


FIGURE 7.3 Plywood

The use of plywood as a building material increases yearly. Plywood is a highly acceptable structural material that lends itself to precutting, prefabrication and modular-home construction. The hardwood plywoods offer an almost unlimited number of decorative possibilities and are easy and economical to install and maintain.

Shingles and Shakes

The hand-split shingle or shake was one of the first exterior covering materials used in this country, dating back to early colonial days. The cob fists first made them from white pine, often smoothing the split surfaces on a “shaving horse.” The early settlers in the Pacific Northwest found the coastal natives living in wood “long houses.” Cabins made by these early settlers still are intact today.

What made shingles and shakes so durable was western red cedar wood, which is highly resistant to rot and decay. Most of the wood shingles and shakes made today in this country are western red cedar. Other desirable characteristics of this wood are its fine, even grain, its exceptional strength, its low weight, its low rate of expansion and contraction with changes in moisture content and its high impermeability to water.

The difference between a shingle and a shake is that a shingle is sawed and a shake is split. A shake may have a sawed back and still be called a shake.

Shingles that are properly applied to walls should last the life of the structure. When applied to roofs, their life expectancy decreases as the slope of the roof decreases and the grade of the shingle decreases. A premium shingle on a normal house roof with a 45-degree slope should last 20 to 25 years in most parts of the country.

WOOD FLOORING

Wood flooring can be made out of either hardwood or softwood. Its long-standing popularity comes from its natural appearance, its durability, its comfort underfoot and its ease of installation and maintenance.

Although the first settlers’ homes probably had dirt floors, it wasn’t long before wood floors became standard features of colonial houses. Those first floors were made of wide softwood planks. Gradually, as manufacturing processes improved, the narrow hardwood-strip floors became the most popular. There has been, however, a recent increase in demand for the old random-length, wide-plank flooring. When more formal houses were desired, small pieces set in intricate designs called parquet floors were installed. Wood blocks also are used for flooring.

The bulk of wood flooring is made from 12 different tree species. The most popular hardwood used for house floors is oak, followed far behind by the other hardwoods—maple, birch and beech. The two most popular softwoods are southern pine and then Douglas fir. Far behind them come western hemlock, eastern white pine, ponderosa pine and half a dozen other woods.

More than 70 % of all wood flooring is from about 20 species of oak, which is divided into the two broad classifications of white oak and red oak. With the exception of appearance, there is little difference between them for flooring purposes. For floors that take an extra amount of abuse, sugar maple makes a good flooring for it's the hardest and the most wear-resistant.

Installation

Wood-strip flooring may be installed over wood subflooring covered with polyethylene film on top of which are set 1-inch by 2-inch wood strips 16 inches on center.

The handling of the flooring material on the site is very important. If properly shipped, it still will be at the 6-percent to 8-percent moisture content that was obtained by the kiln-drying process. When exposed to moisture, the flooring will quickly absorb it, swell, twist and otherwise get out of shape and will not fit well together. Furthermore, flooring that's laid moist will shrink in the dry winter inside air and leave open joints between adjacent strips.

The laying process is started by nailing down a strip next to the wall. The nails are driven through the top of the board close to the wall so they will be covered by the baseboard. Subsequent strips are fitted lightly against each other and blind-nailed to the subflooring or 1-inch by 2-inch wood strips.

Strip flooring can be laid in various patterns. The simplest and most common method is to run all the strips in the same direction. Another method is to lay the boards parallel to all four sides of the room. This pattern is called “log cabin.” Parquet floor designs are made by cutting the strips into small pieces and laying them in a geometrical pattern. It is possible to make a very complicated design by using small pieces and woods of different colors.

If the flooring isn't prefinished, it must be scraped by hand (a process that some people think brings out the best look in the wood) or sanded with a machine.

Wood blocks can be installed similarly to strips or attached with an adhesive. Wood planks sometimes are laid to simulate old plank floors by using pieces of random widths and lengths. The floor may be blind- nailed or pegged.

CONCRETE

After wood, the most important building material in house construction is concrete. It is used for foundation footings, cellar floors and walls, sidewalks, driveway, garage floors and septic tanks. Concrete has four desirable qualities that make it a good building material: It is strong and will support heavy loads; it's watertight and therefore is good for subsurface installation; it's extremely durable, which makes it ideal for footings and foundations that must last the entire life of the house; and it's work able and may be poured into forms and troweled to obtain a smooth or designed surface.

Concrete is a mixture of portland cement, water, fine aggregate and coarse aggregate and admixtures. When portland cement is mixed with water, a chemical reaction takes place. The mixture sets and then hardens into a solid mass that will stay solid forever. Detailed information on concrete manufacture is included in Section 9.

White portland cement is used for special purposes where the white color is desirable, such as in pre-cast walls, terrazzo, stucco and tile grout. It also is used if a color will be added to the mixture. There also are several other types that are used for nonresidential construction purposes.

MASONRY

A brick made of clay is one of the oldest building materials. There is little recorded history that does not mention brick and other masonry materials for building. Today, it's widely used for wall construction in houses in almost every part of the country and for many miscellaneous purposes ranging from patios to walls to fireplaces. The cement block also has developed into a major residential building material. Primarily used for basement walls, it also is used for complete wall construction or is covered with a veneer of stucco, brick or wood.

Masonry used for exterior walls must, as a minimum, be strong, watertight and durable. Its appearance varies widely in color, texture and pattern. Masonry is broken down into the two broad classifications of clay masonry units and concrete masonry units.

Clay Brick and Tiles

Solid-clay masonry units are called bricks and hollow units are called tiles. These units are made of surface clays, shales and fire clays. All three are compounds of silica, alumina and varying amounts of metal oxides and other impurities. Metal oxides affect the final color of the brick.

Surface clays are sediments that are found near the earth’s surface. Shales are a type of clay that has naturally been subjected to high pressure and has become quite hard. Fire clays are found deep within the earth and have to be mined out. They have refractory qualities (resistance to heat).

Clay Brick and Tile Classification and Properties

The term brick means a solid masonry unit. Cored brick may have from three to more than 20 core holes, making up to 25 % of the total brick volume, and still be classified as a solid unit. Bricks may be custom made, but most are produced in standard sizes and shapes.

The properties of the brick depend on the characteristics of the clay used and the manufacturing process. Bricks with the highest compression strength and the lowest absorption rate usually are made by the stiff-mud process and burned at high temperatures. In general, the higher the burning temperature, the higher the compression rate. Well-made bricks are very durable. The only action of weathering that has any significant effect on them is alternate freezing and thawing in the presence of moisture.

The natural color of brick depends on the chemical composition of the clay used, the burning temperatures and the amount of oxygen used in the burning process and the length of time the brick is burned. Colors range from light grays and creams to dark reds and blacks. Under-burning tends to produce lighter colors and over-burning produces darker colors. Under-burned bricks, however, are softer and more absorptive and have decreased compressive strength. Over-burning produces a dark clinker brick that's hard and less absorbent and has increased compressive strength.

Textures range from very smooth, resulting from the pressure exerted by the steel dies, through fine and medium to those that have been marked by cutting, scratching, rolling, brushing or otherwise roughing up the surface as the clay leaves the die.

Fire shrinkage increases with higher temperatures at an uneven rate, resulting in bricks of uneven sizes. This problem is well acknowledged and builders accept bricks with size variations.

Hollow Masonry Tile Classification and Properties

The term hollow tile means a hollow masonry unit with the core holes exceeding 25 % of the total tile volume.

Structural clay tile is produced as load bearing and non-load-bearing. When designed to be laid with the cells in a horizontal plane, the unit is called side-construction or horizontal-cell tile. When it's designed to be laid with the cells vertically, the unit is called end-construction or vertical-cell tile.

Structural facing tile is available as glazed or unglazed. Glazed tile is produced from a high-grade, light-burning fire clay to which a ceramic glaze is applied that fuses into a glasslike coating on the tile during the burning process. Unglazed tile is produced from light-burning or dark- burning clays and shales and may have smooth or rough textural finishes.

Architectural terra-cotta is made-to-order decorative glazed tile used as a veneer to make a multicolored interior or exterior wall.

Concrete Brick and Block

Solid concrete masonry units are called bricks and hollow masonry units are called blocks. They are made of a relatively dry mixture of cementitious material, aggregates, water and admixtures. The cementitious material usually is portland cement (either the normal or high-early-strength type), portland blast-furnace slag cements, fly ash, silica flour or other pozzolanic (ash) materials.

The primary factor in the selection of aggregates is their availability locally. They are classified according to their weight as dense or normal. These classes include sand, gravel, crushed limestone and air-cooled slag. Lightweight aggregate includes expanded shale or clay, expanded slag, coal cinders, pumice and scoria.

A few admixtures have been found to be beneficial in concrete brick and block manufacture. Air-entraining agents increase the plasticity and workability and distribute minute air bubbles uniformly throughout the hardened concrete, increasing its ability to withstand frost action. They also improve the appearance and reduce the amount of breakage of freshly molded units. Water-repelling agents such as metallic stearates reduce the rate of absorption and the capillarity of the units. Accelerators (usually calcium chloride) speed up the hardening during cold weather. Workability agents are used to compensate for poorly graded aggregates.

Concrete Brick and Block Classification and Properties

Many of the physical properties of concrete blocks are similar to regular concrete, which was previously discussed. There are, however, some important differences. Concrete bricks and blocks are made with a substantially lower percentage of concrete in the mixture and a much lower water-to-cement ratio than regular concrete. Fine aggregate is used and often is made of porous or lightweight materials. Unlike structural concrete, blocks and bricks contain a relatively large volume of inter-particle void spaces between the pieces of aggregate that aren't filled with cement.

The compressive strength of the units is highest and the water- absorption rate lowest when they are made of sand and gravel, limestone or air-cooled aggregate, in that order. It is less for units made of expanded shale, expanded slag, cinders, pumice or scoria, in that order.

Bricks and blocks are available in a wide variety of surface textures for aesthetic and structural reasons. The texture is varied by controlling the gradation of the aggregates, the amount of water used and the degree of compaction at the time of molding. The surface may be ground to obtain an exact size. The face contour is controlled by using a face mold.

Most concrete blocks made with portland cement range in color from white to black and tan to brown. Other colors can be obtained by adding mineral-oxide pigments to the concrete mixture before it's cured.

Mortars

Mortar is a mixture of cementitious materials (portland cement, lime, masonry cement and sand and water). It is used to bind the individual masonry units together and to the other building elements. It also seals the spaces between the masonry units, compensates for the size variations, binds the units to the metal ties and reinforcing (if any) and improves the appearance of the wall aesthetically by creating shadow lines and /or color effects.

Mortar Properties

Mortar is laid while it's soft; later it hardens. In its soft state, it must have good workability. To be workable, the particles must not separate, must spread easily and must hold the weight of the units firmly enough, with out sagging, dropping or smearing, to permit their alignment.

The workability of mortar is affected by its water-retention capacity, which must prevent the moisture from bleeding into the dry masonry units that tend to attract it. When this happens, a thin layer of water forms between the mortar and the masonry unit and the bond is weakened substantially. When the mortar hardens, its most important quality is its bond strength. Bond strength is affected by the type of mortar mixture used, the type of unit being bonded, the workmanship and the curing.

The durability of mortar is measured by its ability to resist damage caused by the natural cycle of heating and thawing. Correctly installed mortar should last 35 years or more before requiring any maintenance. The addition of an air-entraining agent to the mixture substantially improves the durability of mortar.

The compressive strength of mortar is controlled by the amount of portland cement in the mixture. The more cement, the higher the compressive strength; the more water, the less the compressive strength. This is rarely a problem in residential construction, however.

Cracked or Loose Mortar Joints

Mortar that's not perfectly installed will, in time, become soft, crack and fall out. This will, in turn, weaken the wall and allow water to seep through. The joints can be inspected visually and by poking them with a pointed instrument. Defective joints should be re-pointed.

IRON

Iron and steel products are found throughout a house. Nails, beams, plumbing fixtures, hardware, appliances, cabinets, electrical components and heating systems all contain iron or steel.

Iron is an element found all over the earth. In fact, about 5 % of the earth’s crust is iron and possibly even a higher percentage of the earth’s molten core is iron. It is rarely found in its metallic form, however. Instead, it's usually combined with oxygen and mixed with other minerals. Iron ore is a mixture of iron, oxygen and other minerals in a combination containing enough iron to make it economically feasible to extract the iron.

Pure iron is soft and has little usefulness. It is hardened by adding small amounts of carbon and other elements. Steel is a mixture of iron and 1.2 % carbon. Cast iron is a mixture of iron and substantially less carbon, while wrought iron is a mixture of iron and substantially more carbon.

Materials

Iron ore is the primary raw material. It is mined from either underground mines or open-pit mines. The largest mines in the United States are in the Lake Superior area. Good iron ore may contain as much as 70 % iron. Fuel is necessary to produce iron from the ore. Coal, oil and natural gas are all used as fuels.

Fluxes are materials used to separate the impurities. Basic fluxes are limestone and dolomite that are mined. Acid fluxes are sand, gravel and quartz rock that are taken from quarries. Fluorspar, a mineral that also is mined, is a neutral flux used to make the slag more liquid.

Refractories, like fluxes, are basic or acid. They have high heat resistance and are used to line the steel-making furnaces. Ganister, which is a quartzite rock, is an acid refractory. Magnesia, a basic refractory, is a mineral that's extracted from seawater.

Classification of Irons

Cast Iron. By combining selected pig irons, scrap metals and alloying elements, cast iron can be made with increased hardness, toughness, corrosion and wear-resistance. This permits the casting of complex shapes difficult to produce by machining or rolling. Bathtubs, pipes and radiators often are made of cast iron.

Malleable Cast Iron. This type of iron contains a mixture of raw materials that improves its breakage resistance by increasing its toughness and ductility. It is used for builders’ hardware.

High-Strength and Nodular Cast Iron. By adding molybdenum, chromium and nickel to the blend, a high-strength cast iron is produced that's used for special purposes. By adding magnesium, nodular cast iron is produced that has high strength, ductility, toughness, machinability and corrosion resistance.

Wrought Iron. Mechanically mixing iron silicate with the pig iron and rolling it results in an iron with packed and elongated particles of iron and slag, giving it a fibrous grain structure. The iron becomes tough, ductile and easy to weld. It has low compressive and tensile strength but high rust resistance and is used for exterior rails, ornaments and pipes.

STEEL

Materials

The basic materials of steel are pig iron, carbon, phosphorus, sulfur, manganese and silicon. These materials, when present in the pig iron as it comes from the blast furnace, are called residual elements. When they are added, they are called alloying elements.

Properties

The properties of steel can be changed by adding various alloys to it, such as aluminum, copper, lead, chromium, nickel, molybdenum, tungsten, vanadium, tellurium, titanium and cobalt.

The American Iron and Steel Institute (AISI) has a letter and numerical designation system for identifying the alloys that have been added to a type of steel and how it was made.

Alloy steels are high in cost and are used only where carbon steel with similar properties isn't satisfactory. Alloy steels are used for motor parts, such as those found in vacuum cleaners, washing machines, tools and appliances.

Stainless steel has a high resistance to corrosion, a characteristic that's produced by adding chromium. When chromium oxidizes, a thin, air tight layer of chromium oxide forms over its surface that prevents corrosion. Stainless steel is classified by the AISI as martensitic steel when it contains 12 to 18 % chromium; ferritic steel when it has 18 to 27 per cent chromium; austenitic steel when it has 16 to 26 % plus 3.5 to 22 % nickel and sometimes 5.5 to 10 % manganese.

Martensitic chromium steel has moderate corrosion resistance, high- strength hardness and abrasion resistance. It is used for cutlery and bearings. Ferritic chromium steels have high corrosion resistance and are used as trim on such items as automobiles, appliances, gutters and down spouts, range hoods and range tops.

Austenitic nickel-chromium steels are the most common stainless steels. They have excellent corrosion resistance and high strength and ductility and are chemically resistant. They are used for kitchen sinks, countertops and appliances, kitchenware and utensils.

Heat-resisting steel obtains its characteristics with the addition of 4 to 12 % chromium. It retains its physical and mechanical properties at temperatures up to 1,100 degrees.

ALUMINUM

Aluminum is a modern building material that was unknown 200 years ago and not commonly used except for jewelry and tableware until the twentieth century. Its use has doubled in the past 15 years.

Materials

Aluminum is the most plentiful metal, but it's never found free like gold or silver. It always is combined chemically with other elements. Almost all rocks contain some aluminum. It isn't economically profitable to ex tract the aluminum, however, unless the ore has an aluminum-oxide con tent of at least 45 % . Aluminum ores are called bauxite. Almost all American bauxite is found in Arkansas, which, unfortunately, supplies only about a quarter of the country’s need. The rest is imported.

Products Made from Aluminum Parts

The principal aluminum products used in residential construction are doors and windows, gutters and downspouts, siding and insulation. Each of these products is covered in its respective section in this guide.

Sheet aluminum is used for many other household building products. Among them are air-conditioning and heating ducts, awnings, flashing, garage doors, range hoods, letters and numbers, shingles, termite shields, terrazzo strips, venetian blinds and weatherstripping. Extrusion aluminum products used in houses include builders’ hardware, fascia plate, gravel stops, railings and thresholds. Bar aluminum products include grating and screws. Wire aluminum is used for nails and screens. Aluminum foil is used for insulation and vapor barriers. Cast aluminum is used for hardware, grilles, letters and sculptural relief panels.

GLASS

The use of glass dates back to prehistoric times, although the exact place and date of its origin are unknown. The oldest known specimens of glass were from Egypt, where, around 2000 B.C., the glassmaking industry was well established. Glass was used for Roman window panes at the time of Christ. The process for casting glass was invented in France in 1688.

Types of Window Glass

The most common window glass used in houses is standard sheet glass. In the building trade, the thickness of glass is known as its strength. The most common types are single strength and double strength.

Single strength is used only in small lights (panes) and in areas of low wind velocity. The MPS states that nothing less that single-strength glass should be used. The strength of the glass should be increased as the size of the window increases and in areas of high wind velocity. Double- strength window glass is suitable for most regular use.

Plate glass tends to distort the view less than standard glass and is used where good vision is important, as in a picture window. It is more expensive than standard or double glass.

To obtain better insulation, two pieces of single- or double-strength glass may be hermetically sealed together with an airspace between them. This is known as insulating glass. It often is used in electrically heated houses. Each light of glass comes with a label that shows the manufacturer’s name, the quality and the thickness.

Glass that's tinted or bronzed reflects heat and has some insulation qualities. By reflection, it reduces the ability to see inside the house from the exterior.

Types of Door Glass

According to the MPS, single-strength glass should be used in doors only when the area of the pane isn't more than 6 square feet and the glass isn't less than 10 inches above the floor. Double-strength or stronger annealed glass is required when the size of the pane is increased. When the door does not have bars, special safety glass should be used. Safety glass may be made by laminating two sheets of single- or double-strength glass to a tough plastic sheet. Shower and tub enclosures also should be made of safety glass.

Fully tempered glass often is used in doors that might be hazardous if a child ran into them. This glass breaks up on impact into small pieces rather than sharp-edged pieces. Tempered and laminated glass may be identified by the permanent label on it showing the manufacturer’s name, the type of glass and the thickness, which should be left visible on the lower side when the glass is installed. Glass that meets rigid safety standards also may have an Underwriters’ Laboratories label permanently attached on it.

RESILIENT FLOORING PRODUCTS

Resilient flooring products have dense, nonabsorbent surfaces and the ability to spring back into place. Linoleum was the first resilient flooring. It was discovered in England more than 100 years ago. After World War I, asphalt tile evolved from a troweled-on mastic flooring. After World War II, vinyl asbestos and vinyl flooring products were introduced. They are available in a wide variety of textures and colors. New vinyl products a being introduced continuously and they appear to be, along with carpeting, the floor covering of the future. Resilient flooring is manufactured in sheet and tile form. Wall base, thresholds, stair treads and feature strips are available to make complete matching flooring installations possible.

Linoleum

The term inlaid linoleum is used for all types of true linoleum products, including plain, marbleized, jasper and molded types, to distinguish them from a thin-faced or enameled felt sheet product typically made in rug sizes that often is mistakenly referred to as linoleum. This inexpensive product isn't suitable for permanently adhered installation and often is found as a temporary covering over damaged floors in older houses.

Linoleum offers good grease and burn resistance, average durability and ease of maintenance, fair resistance to stains, good resilience and some soundproof quality. It has poor resistance to alkalies and indentation, however, and it shouldn't be installed on floors that are on or be low grade.

Asphalt Tile

Asphalt tiles traditionally have been classed into several groups. The least expensive group is group B, which is quite dark in color. Group C is of medium darkness and medium price and group D is light-colored and more expensive. Group K is the most expensive and includes many special colors and patterns.

Asphalt tile provides good resistance to alkalies, fair resistance to burns and indentation, fair durability and ease of maintenance but poor grease and stain resistance (except for an uncommon grease-resistant type) and poor resilience and quietness. A major advantage is that it may be installed below grade, on grade or above grade and often is used over cement basement floors. It also is expensive.

Rubber Tile

Rubber tile is flexible and has a high-gloss surface. It is very resistant to burns and stains, has good resilience, sound absorption and durability. It has fair resistance to grease, alkalies and indentation. Like asphalt tile, rubber tile may be installed below grade, on grade or above grade. In many ways, it's superior to asphalt tiles but is more expensive for comparable colors.

Cork Tile

Plain cork tile has an attractive appearance. It is a very resilient and a very quiet floor covering. Its resistance to grease, alkalies, stains, burns and indentations, however, is poor. It also is difficult to maintain and has poor durability. A clear sheet of vinyl sometimes is fused to the surface. This substantially improves the ease of maintenance and grease and stain resistance. It decreases the resiliency and soundproof qualities, however, and changes the appearance. Both plain and vinyl cork tile may be in stalled above grade and on grade but shouldn't be installed below grade.

Vinyl Asbestos Tile

Vinyl asbestos tile provides good resistance to grease, alkalies and burns. It is easy to maintain and quite durable. This tile, however, has poor stain and indentation resistance and poor resilience and quietness. It may be installed anywhere, which is a major advantage, and it represents a good value for the price. Because of the dangers associated with asbestos, it no longer is manufactured in the United States.

Solid Vinyl Tiles

Solid vinyl tile is available in a wide variety of colors. It is very durable, is quiet and has good resistance to grease, alkalies and stain. It also has fair resilience and resistance to burning and indentation. Solid vinyl tiles are relatively easy to maintain and may be installed anywhere. Usually, vinyl is more expensive than vinyl asbestos tile of a similar color and design.

Rag-Backed Vinyl Tiles and Sheets

In general, these products offer good durability and are easy to maintain. They have good resistance to grease, alkalies and stain and are fairly resilient and quiet. They are susceptible, however, to damage by burning and indentation. Solid-backed vinyl flooring may be installed anywhere, but rag felt-backed vinyl flooring should be installed only above grade.

Selection Criteria

Once the decision has been made to use a resilient floor covering rather than wood, carpet or concrete, a decision also must be made regarding which type of tile to use. The first consideration is that of moisture. Ground moisture generally affects tiles laid on floors that are below ground level or on concrete slabs that aren't completely protected by vapor barrier. Wood subfloors over crawl spaces protected by a vapor barrier generally are free of ground moisture, as are floors over basements and second or higher floors.

Linoleum, cork and rag-backed vinyl are all attacked by ground moisture and shouldn't be installed where it's present. Concrete releases moisture as it cures and care must be taken not to install linoleum, cork or rag-backed vinyl on any concrete floor no matter where it's located unless it's fully cured.

Surface moisture coming from spilled water or floor mopping, common in halls, laundry rooms, bathrooms and kitchens, tends to seep through the seams and affect the adhesives and subflooring. Sheet products tend to reduce this problem and special water-resistant adhesives should be used whenever surface moisture may be present.

Floors laid in kitchens often are subject to grease and alkalies that are found in many cleansers. For this reason, asphalt and cork tiles generally shouldn't be used in the kitchen. Linoleum has a high grease resistance but a low alkali resistance and must be kept waxed when installed in the kitchen.

Durability means the flooring is serviceable and an attractive appearance can be maintained over a long period of time. Cork has poor durability and should be used only when appearance and quiet are the primary considerations of choice. Because linoleum has low durability, it's used when price is a factor and in low-wear areas. Generally, the vinyl tiles and sheets are the most attractive and offer the most desired features. Unfortunately, they also are the most expensive and the final selection usually is based on a weighing of the poorer characteristics of the other products against their lower cost.

CARPETING

Carpets were woven in Babylon 5,000 years ago. Egyptian pharaohs carpeted palace floors around 1500 B.C. Oriental carpet weavers returned with the crusaders to fourteenth-century Europe and did a lively business.

Carpeting continues to grow in popularity as a floor covering for all rooms in the house. Since World War II, American carpet production has increased more than 400 % . The FHA has reversed a long standing policy and now accepts wall-to-wall carpeting over subflooring as an approved floor material and has established acceptable minimum standards. This wide acceptance of carpet can be attributed primarily to technological advances in carpet production. Most people choose carpet for its comfort and decorative value. As a bonus, they get its excellent sound-reduction characteristics.

Raw Materials

Backing yarns hold the pile tufts in place and provide stiffness to help the carpet lie flat. The most common materials used are jute (sisal fiber), kraftcord (wood pulp fiber), cotton, nylon and rayon.

Wool is the traditional pile fiber. Its good performance has been proven over many years and it's the standard by which the other fibers are judged. Most carpet wool is imported. Wools from various regions have different characteristics. Woolen yarn, which most carpets are made of, is composed of interlocked long and short fibers from 3’/2 to 5’/2 inches long.

Nylon, a synthetic fiber, accounts for about half of the residential carpet now being made. There are two basic types of nylon, known as type 6 and type 66, which differ chemically and in their color-retention characteristics. Otherwise, they are very similar. Staple nylon fiber is composed of 1 1/2-inch to 6-inch fibers spun into yarn. Continuous- filament nylon consists of bundles of continuous fibers that are formed into yarn without spinning.

Acrylics and modacrylics (modified acrylics) are synthetic fibers. Acrylic is a polymer composed of at least 85 % acrylonitrile. Mod- acrylic is a polymer composed of between 35 and 85 % acrylonitrile. Polypropylene is a synthetic fiber mostly produced in bulked continuous- filament yarn.

Cotton, rayon and acetate haven't proven very satisfactory for car pet construction but still are being used occasionally.

Performance Characteristics

A major factor in carpet performance is the fiber used. Pile thickness, weight and density also are important factors, plus the overall construction of the carpet. Durability is the ability of the carpet to resist destruction or loss of the fibers and is the overall measure of its serviceable life. The carpet must resist wearing away from foot traffic, which causes the fibers to break.

Alkalies are found in foods and cleaning materials. Acids also are common in food. Carpeting that will be exposed to either of these must have a high resistance.

Insects and fungi attack natural fibers but don't attack synthetic fibers. Wool carpeting, however, can be treated during manufacture, thereby greatly reducing its vulnerability.

Cigarette and other burns are a constant hazard many carpets are ex posed to. Synthetic fibers tend to melt and the heated area is very visible afterward. Wool burns, but more slowly than synthetic fabrics.

The attractiveness of the carpet is decreased when the carpet compresses under a heavy load. This tends to be related more to the car pet’s construction than to the type of fiber. The ability of the carpet to re cover from being compacted by a load is called crush resistance. The pile density, the spacing of the tufts and the tightness of yarns affect crush resistance more than the type of fiber. The same is true of the ability of the carpet to retain the surface texture imparted during manufacture.

Much has been written about the ease of maintaining carpeting as compared with other floor coverings. About the best that can be said, however, is that no form of flooring is clearly superior under all conditions. Carpeting has proved to be easy to maintain in many household situations but difficult, if not impossible, in others. Stains and grime sometimes are impossible to remove.

Wool offers excellent texture retention, durability, appearance and ease of maintenance. It has excellent crush resistance and when chemically treated, it's resistant to insects and fungi. It provides good resistance to abrasion, burns, compression, staining and soiling, but it shouldn't be used in kitchens and bathrooms for it has a low resistance to alkalies and acids and does not wet-clean easily. In the winter, wool carpeting builds up static electricity and gives electric shocks. It also is expensive compared to other carpet fibers.

Nylon now accounts for more than half the fiber used in residential carpeting. It is low in cost and is available in many bright, popular colors. It offers excellent durability, appearance retention and texture retention and is easy to wet-clean and , generally, to maintain. Nylon also provides excellent resistance to abrasion, alkalies, acids, staining, insects and fungi and makes a good kitchen, bathroom or family-room carpet. It also affords good compression and crush resistance but does soil very easily and , like the other synthetics, melts when burned and builds up static electricity.

Acrylic has most of the good features of nylon. It is somewhat less resistant to acids but has better general soil resistance. The appearance and high durability of acrylic compare favorably with wool and it's much less expensive. Modacrylic has about the same characteristics as acrylic.

Polypropylene is the newest of the synthetic fibers and is gaining in popularity. Its principal use is for indoor-outdoor and kitchen carpeting. It has low moisture absorbency and high stain resistance. The colors are locked in chemically and are very fade-resistant. Although it's easy to wet-clean, polypropylene isn't very resilient and its resistance to crushing and compression is poor.

Mixtures and blends of the various fibers are common. In general, a carpet must consist of about a third of a fiber before it takes on the characteristics of that fiber. As the various synthetic fibers are improved, there seems to be less blending of the fibers.

Standards of Quality

To date, the carpet industry still has failed to adopt industry-wide standards of quality. Several of the major fiber manufacturers and the Wool Institute have established standards for the use of their respective fibers and their labels of approval are good starting points on which to make a selection.

The FHA has issued a set of minimum standards that may become the basis of an overall industry standard. Few carpets indicate whether or not they meet the FHA minimum standards. Many dealers, however, have the information and will issue a certificate for those products that com ply. Federal law requires that all carpets be identified with a label that states the fiber content.

Carpeting that has been correctly selected for the area in which it's being used and is well cared for should last from 7 to 15 years.

Cushioning

All carpeting should be laid with cushioning that's either bonded to the backing or installed separately. Cushioning substantially increases resilience and durability. Separate cushioning is called padding. With loomed carpeting, foam or sponge rubber often is bonded directly to the back of the carpet at the mill.

Felted hair makes the most economical conventional padding. It is made with a waffle design that provides a skid-proof surface and improves resiliency. Sometimes it's reinforced with a jute backing or a burlap center. Another type of padding is made of felted hair or jute and coated on one or both sides with rubber to hold the fibers together and to provide additional resilience.

Rubber padding, in addition to being bonded directly to many car pets, also is available in separate sheets. A layer of burlap usually is bonded to one side to facilitate installation by permitting a smooth, even stretch of the carpet, which is difficult to accomplish on top of plain rub ber. Rubber padding, in general, is superior to felted hair, but it's more expensive and shouldn't be used on radiant-heated floors.

MISCELLANEOUS ROOFING and SIDING PRODUCTS

Asphalt Roofing and Siding

Asphalt roofing and siding products are classified into saturated felt products, roll roofing and siding and shingles.

Saturated felt is impregnated with asphalt but is otherwise untreated. It is used for shingle underlayment, sheathing paper and lamination strips for built-up roofing. It is available in 15-pound and 30-pound weight per square (the amount of material required to cover 100 square feet of roof).

Roll roofing and siding come both smooth and coated with mineral aggregates. Some are in split rolls that, when applied, give a patterned edge.

Shingles are classified as either strip shingles or single shingles.

Standards of Quality

A leaky roof means rotting attic timber, stained ceilings and walls and damage to the rest of the house and its contents. A roof lasts for substantially less time than the whole house and the quality of the shingles will determine how long the roof will last before it will have to be repaired or replaced. Roofing is damaged fastest by wind and sun; therefore, in the hot climates and in high-wind areas of the country, quality becomes even more important.

Fortunately, the Underwriters’ Laboratories tests and rates most of the roofing being produced today for fire resistance, wind resistance, quantity of saturant and efficiency of saturation, thickness and distribution of coating asphalts, adhesion and distribution of granules, weight count, size, coloration and other characteristics of finished products be fore and after packing.

In high-wind areas, a minimum of Underwriters’ Laboratories class C wind-resistant roofing should be used. More fire protection and usually longer trouble-free life are obtained from wind-resistant class B and class A shingles. In low-wind areas, wind-resistant shingles aren't necessary, but a minimum of class C should be used to provide fire protection and satisfactory life. Classes B and A are still better quality.

Shingles are sold by weight per square. The higher the weight, the longer the shingle will last and the more it will cost. Because labor is a big factor in the roofing cost, however, it pays to buy heavyweight shingles for their total cost in the long run will be less. A heavy shingle weighs more than 30 pounds per square.

Slate Shingles

Slate is a natural mineral that's taken from a quarry. A standard roofing slate is 5/16 of an inch thick and may be 10 to 24 inches in length and 8 to 14 inches wide. Slate is a durable roofing material that may last through out the life of the house if cracked and missing slates are replaced on a regular basis. Because slate is heavy compared to other roofing materials, the roof framing must be especially strong to support a slate roof. The other principal disadvantage is that slate is expensive compared to other roofing materials. It often is used on houses of the English and French styles.

Tile Shingles

Roof tiles are manufactured the same way that wall tiles are. They are available in a variety of styles and are used on houses of the Spanish, Italian and Greek styles. Tile makes an excellent roofing material, especially in climates where the temperature does not fall below freezing.

Gypsum Products

Gypsum (hydrous calcium sulfate) is a common, rocklike mineral found throughout the world, usually combined with clay, limestone and iron ox ides. It is unique because when it's intensely heated (calcined), it gives up some of its water content and becomes powdered. When cooled, gypsum can be restored to its original rocklike state by adding water. This mixture remains plastic for a while and then sets. During this plastic state, it can be easily shaped and worked. Gypsum has been used for 4,000 years for construction. Plaster of Paris, an early form, received its name from the mines under Paris where gypsum was found.

Gypsum also offers unique fire-resistant qualities. When exposed to heat, the surface releases its water in the form of steam. This absorbs some of the heat and delays the raising of the gypsum’s temperature to above 212 degrees. When the water is released, the surface becomes calcined and protects the underlying gypsum from the heat. This dual action makes gypsum an excellent fire-resistant material. Other materials used to manufacture gypsum products are aggregates, mineral and organic fibers and lime.

Classification of Gypsum Board Products

Regular wallboard is surfaced with gray liner on one side and calendered manila paper on the other side. Many are produced with tapered edges. Pre-decorated wallboard has a decorative finish on one side. Insulating wallboard is regular wallboard with a bright-finish aluminum foil bonded to the back. It often eliminates the need for a separate vapor barrier. Fire- resistant (type X) wallboard has a core especially formulated with additives and glass fibers for greater fire resistance. Water-resistant wallboard is made by using a multilayered covering of chemically treated paper and a gypsum core formulated with asphaltic adhesives.

Backing board serves as a base to attach other types of wallboards or tiles. It differs from other types of wallboard in that both surfaces are covered with a gray liner paper not suitable for decorating. It comes in its regular form, fire resistant (type X) or with insulating foil. Backing board is made with a highly water-resistant vinyl surface for use as a base for tile in areas such as stall showers that are subject to direct wetting.

Gypsum sheathing is used as a base for other external sidings. It usually is made of water-resistant gypsum core completely enclosed with a firmly bonded water-repellent paper that eliminates the need for sheath ing paper.

Formboards are used as permanent forms for gypsum-concrete roof decking. They are surfaced on an exposed face and longitudinal edges with calendered manila paper treated to resist fungus growth. A vinyl- faced board, which provides a white, highly reflective and durable surface, also is available.

Gypsum lath boards are used as a base for plastering. They consist of a gypsum core enclosed by a multilayered fibrous paper covering designed to assure good bond with gypsum plaster. The main types are plain, perforated, insulating and fire-resistant (type X).

Classification of Plaster Products

Neat gypsum base-coat plaster does not contain any aggregates. It comes in varieties with fiber already added. It usually is combined on the job with the aggregates and is used for base coats over metal or gypsum lath, gypsum and clay tile and concrete block and brick. It also is used as a scratch coat over metal lath and , with sand added to it, as a brown coat.

Wood-fibered base-coat plaster consists of calcined gypsum integrally mixed with selected coarse cellulose fibers that provide bulk and good coverage. It is used over the same bases as neat plaster, but it pro vides greater fire resistance than neat and other sanded base-coat plasters.

Ready-mixed base-coat plaster is neat plaster to which aggregates and all other additives except water are added at the mill.

Bond base-coat plaster, in addition to plaster, contains lime and other chemical additives that improve the bond with concrete and other nonporous surfaces.

Gauging finish-coat plaster consists of coarsely ground gypsum of low consistency. It generally is used without aggregates. The addition of fine-silica sand, however, increases its crack resistance when it's used over base-coat plasters containing lightweight aggregates.

Keene’s cement is similar to gypsum gauging plaster except that it's burned dry in a kiln instead of in a calciner or kettle. The result is a denser material with greater impact, abrasion and moisture resistance.

Other types of plaster used in house construction are gypsum-lime putty-trowel plaster and Keene’s cement-lime putty-trowel plaster, both of which are made by adding lime. Keene’s cement-lime-sand-float plaster is used where a minimum of cracking is desirable. Prepared gypsum finish plaster is available in a variety of mixtures, all of which require only water to be added on the job. Veneer (thin-coat) plaster is a high strength plaster for very thin applications. Molding plaster is used to make intricate surfaces with close tolerances. Acoustical plasters contain chemicals that form small air bubbles in the plaster to increase its sound- absorption properties.

MINERAL FIBER PRODUCTS

Fiber products are made by combining asbestos fibers, portland cement and water. The mixture is formed under pressure into thin, hard, rigid sheets or pipes. Roof shingles of this material were produced at the turn of the century. The material is completely inert, durable, fire-resistant and maintenance-free. Its main drawback is low resistance to impact.

Classification of Products

Wall siding and shingles and roofing shingles are made in a wide variety of styles, shapes, textures and colors.

Flat sheets are made in sizes from 4 by 8 feet to 4 by 12 feet and 1/8 inch to 2 inches thick. They are used for both interior and exterior applications where a high amount of fire resistance is needed, such as near fireplaces, ranges, ovens and furnaces. They are made with smooth or textured surfaces, with finishes of natural gray, pre-primed for painting or with pigmented plastic coatings.

Insulated panels are made in the factory by assembling layers of insulating core material between flat sheets. These sandwich panels are used for exterior walls, interior partitions and roof decking.

All of the products should conform to the standards set by the American Society for Testing and Materials (ASTM) and bear a label to that effect.

CABINETS

The history of bathroom and kitchen cabinets goes back several hundred years in this country. They were first called ambries and cupboards and were used to store food. The walls in the kitchen between the chimney and the side wall were filled with open and closed shelves.

Prior to World War II, most cabinets were made of wood. Many were built in the mills, while some were constructed on the site by skilled cabinetmakers. After the war, huge mass-production cabinet plants took over the bulk of cabinet production. Most of what can be said about kitchen cabinets is also true of bathroom cabinets, so they are covered together here. Figure 7.4 illustrates typical cabinet construction.


FIGURE 7.4 Cabinet Construction: Typical base cabinet construction, showing component parts. Rails and stiles of frames can be Joined by: (A) mortise and tenon, or (B) dowel joint.

Cabinet Types, Styles, Finishes

Kitchen cabinets are classified by their function as base cabinets, wall cabinets or miscellaneous cabinets that include broom cabinets, oven cabinets, lazy Susans, fruit and vegetable bins and tray holders. Bath room cabinets, also known as vanities, are similar to kitchen base cabinets, differing mainly in height and depth.

Both kitchen and bathroom cabinets are manufactured in a variety of styles, the most popular of which are colonial, contemporary, traditional, Mediterranean and Spanish. Woods used in cabinet manufacture are ash, oak, birch, maple, walnut, ponderosa pine, Douglas fir and western hem lock. A variety of finishes such as walnut, ebony, white, nutmeg, fruit-wood, cherry, pecan, birch and oak are used.

Drawer construction varies according to cabinet quality and is a good way to judge the overall quality of the cabinet. In the good-grade cabinets, the drawer sides are connected to the front and back with multiple dovetail joints. Cheaper cabinets have drawers with lock-shouldered and square-shouldered joints.

Factory-made metal cabinets often are used today. Drawers, adjustable shelves, backs, sides and fronts are made of enameled pressed-steel sheets. Doors usually are hollow steel. One sign of the better grades are drawers that move on roller slides rather than on friction slides. Because it's impossible to trim metal cabinets and the variety of sizes available is smaller than the variety of wooden cabinets, it's necessary to carefully plan the space to be filled with a cabinet arrangement.

Installation

Cabinets must be installed level, plumb and true to ensure proper operation. They should be screwed, not nailed, to the wall studs. The screws should go through the framing members.

Cabinets usually are installed by first removing any floor or wall irregularities that will interfere with their plumb and level installation. A base corner unit is installed first and then each additional unit is aligned to it and held in place with a clamp until all the screws are installed and tightened. Wall cabinets are installed similarly, starting with the end or corner unit.

MOLDING

The ancient Greek designers first used molding to divide surfaces into small parts, to create interest and variety and to produce highlights and shadows. Later, the Romans simplified molding designs and substituted various compass and mechanical curves for the freehand design of the Greeks. Molding details of both the Greeks and the Romans have passed down through the centuries and today are the basis of most molding designs.

Molding is made from a variety of hardwoods and softwoods for interior and exterior use. It is made at a mill by special machines that cut, plane and sand the lumber surfaces into the desired shapes. A general rule is that the thicker the piece of molding and the more intricate the design, the more expensive it's .

Most molding used today is “stock” molding of one of the standard sizes and shapes. In the past, architects would design a special molding for a custom house and the mill would make it to the required specifications. Although the practice is rare today, there still are a few mills that are capable of making custom molding.

Interior Applications

The use of interior molding in a modern house may be limited to simple casing around the doors and windows, baseboards and ceiling, although all of these may not be present (see Figure 7.5). In more elaborate houses and in houses that are in the architectural style of a certain period, extensive or elaborate molding may be used. The elaboration may be increased by using two or three pieces of molding together.


FIGURE 7.5 Molding

Cornices

Interior cornices are strips of wood molding nailed to the wall-ceiling joint in such a way that they may project away from the wall with a space between the back of the molding and the wall-ceiling junction. This space may be left unfilled or blocking may be installed in it for better nailing. It may be made large by attaching a frieze board to the wall and ceiling and then attaching the molding. Still more ornamentation may be obtained by adding egg-and-dart molding, dentils, meander or other details.

Mantels

The mantel is the ornamental facing around a fireplace. (It also is known as a mantelpiece, although the mantelpiece is more specifically the protruding shelf portion of the mantel.) Mantels vary from a simple shelf at the top of the masonry to elaborate facing of the fireplace front with wood, marble, limestone or other ornamental material. The opening directly around the fireplace itself, however, must be edged with masonry material and not with wood to prevent charring.

Wainscots

When the upper portion of a wall is finished with a different material than the lower portion, the lower portion is called the wainscot and what ever material it's finished with is called wainscotting. The main part, the lower section, is the dado; the upper edge is the surface or cap. Simple wainscotting is solid wood, plywood, hard plaster, cloth, linoleum or other sheet material. Elaborate wainscoting is constructed of solid lumber paneling usually made in a mill and then installed in large sections. A paneled look is accomplished by nailing wide moldings to the surface of the plywood dado.

Chair Rails

Older houses have horizontal strips of wood nailed to the wall at the height of a chair to prevent marring of the walls by chairs. These may double as the upper rails of the wainscot.

Picture Molding

A narrow wooden molding strip is shaped so that flat metal hooks can be hung from it. The hooks should be nailed into the stud and not just into the plaster.

Bookshelves

Bookshelves may be constructed similarly to cabinets. Generally, they are adjustable rather than rigidly affixed to the walls. A simple adjustable shelf may be made with a series of holes drilled or punched at regular intervals to the case ends or to the back of the case. Pegs or brackets inserted into these holes support these shelves.

Exterior Applications

Windows may be effectively accented with outside casing. When added to metal windows, moldings soften the harsh contrast of metal against siding. Eaves, soffits and rakes look more elaborate with molding and these are used in both colonial and contemporary homes.

Quality Standards and Grades

The Western Wood Moulding and Millwork Producers, in cooperation with the Western Wood Products Association and the Southern Pine Association, publish Moulding Patterns, which has become the standard reference of molding patterns. Most of the stock molding made today is from one of the designs in this guide. This guide also contains the industry grading and other standards.

DOORS

Door Types

There are seven basic types of doors: batten doors, sliding glass doors, folding doors, flush solid doors, flush solid core doors, flush hollow core doors and stile and rail doors (see Figures 7.6 and 7.7). Each of these classifications has several subdivisions.


FIGURE 7.6 Doors


FIGURE 7.7 Door Construction

Batten doors consist of boards that are nailed together in various ways. One common way is to nail two layers of boards at 45-degree angles to each other. Another way is to nail the vertical boards to ones running horizontally (called ledge boards) or brace boards that run at a 45-degree angle. Batten doors are used where appearance isn't important, such as for cellar and shed doors.

Flush solid doors are perfectly flat on both sides and made of planking. This type of door is rare in houses.

Flush solid core doors are made with smooth face panels glued to a core that's made of either a composition material, glued-together wood blocks or glued-together wood pieces. Added strength is obtained by using two layers of face board. Usually strips of the core material are glued around the edge. Solid doors often are used as exterior doors.

Flush hollow core doors also are perfectly flat. They have a core that consists mainly of a grid of crossed wooden slats or some other type of grid construction. The face wood must be three or more plies to give the door strength. The edges of the core are solid wood and wide enough so that hardware may be attached by screwing into the solid edge. These doors are light and are used for interior doors.

Sliding glass doors contain at least one fixed pane plus one or more panes that slide in a frame of wood or metal. The most common type has two panes that provide a maximum of 50-percent ventilation. The three- pane type has fixed end panes and a sliding center pane and provides only 33-percent ventilation. The four-pane type also has fixed end panes with two sliding center panes. It provides 50-percent ventilation.

Accordion folding doors usually are made of wood slats connected with tape or cord forming flexible, drapelike doors. They can be made as long as needed. They usually are designed so that when they are folded, they are about the width of the jamb. Generally, they are hung from ceiling tracks and operate on nylon rollers or glides. They are used to provide a visual screen rather than a sound barrier in such places as closets or laundry enclosures.

The solid wood type of accordion door consists of thin wood slats connected to each other with continuous metal, vinyl or nylon fabric hinges. The woven type is made of vertical wood strips that are 3/8 to 1 inch wide, interwoven basket-weave style with tape. The corded type is made with wood slats similar to the woven type, but the slats are connected with cotton cord.

Stile and rail doors consist of a framework of vertical boards (stiles) and horizontal boards (rails). These stiles and rails usually are made of softwood and give the door its strength. They are connected by using dowels or mortise and tenon joints and are glued together.

What fills the space between the stiles and rails determines the name of the stile-and-rail door style. The spaces in many of these doors are filled with from one to eight solid wood or plywood panels and are known as panel doors. They may be horizontal, vertical, square or some combination of these. When some of the spaces are filled with glass, the door is a sash door. When all of the spaces are glass-filled, it's a French door. Rim-type French doors have one piece of glass and divided-light French doors have multiple, smaller lights.

The spaces also may be filled with wood slats attached to the stiles in such a way that air may circulate between the slats. Standard slats are flat and chevron slats are curved. The slatted doors are known as louvered doors. They are used for laundry areas, furnace rooms, closets and other areas where air circulation is needed and privacy and sound insulation isn't required.

Storm doors, screen doors and combination storm-and-screen doors often are hung outside the regular door to provide additional insulation in the winter and ventilation in the summer. The spaces are filled with glass or screens that are removable so that they can be interchanged from season to season. The frame usually is made of lightweight wood or aluminum. On the self-storing type, the glass and screens slide up and down so that either may be used without removing the other. The disadvantages of this are its high expense and a maximum of only 50-percent ventilation or light available.

Door Operation

Doors can be installed so that they either swing, slide or fold open and shut. The location and use must be considered in selecting which method should be employed.

A swinging door is attached either to the side jamb with hinges or to the ceiling and floor with pivots. Most doors used in houses are the hinge type, with pivots used mainly for the door between the kitchen and the dining room when it swings in both directions. Swinging doors are called right-handed when the knob of the door is on the right side as it's viewed from the side it opens into. Hinged swinging doors provide maximum security, for the hinge can't be removed from the outside when the door is closed. (The pins may be removed from the inside in the closed position.)

The door may fit tightly when closed and can be weather-tight and sound proof. Weatherstripping on the door will increase these qualities. The main disadvantage of a swinging door is that it requires a space to swing into and in some places this clear space isn't available.

Sliding doors slide back and forth parallel to the wall. They may be attached to an overhead slide and operate on nylon rollers or they may be mounted on rollers that roll in a floor track. Sliding doors are popular for use in closets where they don't take up any valuable closet or room space. They may be designed so that two doors are used and each slides past the other. The advantage is that the wall does not have to be cut into to make space for the opened door. The disadvantage is that only 50 per cent of the opening is usable at any one time.

The major disadvantages of doors that slide along the wall surface are appearance and the need to keep the wall space clear of interfering objects. The door also may slide into a pocket in the wall. The advantage of this is that the door becomes invisible and out of the way. This is a costly installation to make, however, and usually some wall studs must be eliminated to make room in the wall for the door.

Folding doors are hung on overhead tracks and move on nylon rollers or slides. They also may have a floor track to guide the folding movement.

Installation

For a door to function properly and appear unblemished, it must be handled and stored correctly before installation. It should be handled only with clean gloves and stored flat on a level surface in a clean, dry, well- ventilated space.

To ensure proper hanging, the door frame should be square and plumb and doors should fit with a total clearance of about 1/16 of an inch in both directions. Too little clearance will cause the door to stick in humid weather and excessive clearance permits the weather and sound to pass through. Inside doors usually require two hinges and outside doors three hinges.

WINDOWS

History

When primitive society moved out of caves and trees, it was into the single-unit, one-story hut. The huts were square, rectangular or round (particularly in parts of Africa), but each one had a single opening and no internal divisions. There was no such thing as a window.

In fact, the simple concept of the window evolved slowly and was preceded by the advent of the two-story house and the floor. At first, one hut would be joined to another if the family needed more room, but there still was no room division. The next development was placing one hut on top of the other. It was at this point that, for all practical purposes, windows and doors became part of architecture. Some archeologists feel that the Mayan society pioneered this growth, while others feel that a more northern aboriginal society was responsible because windows made more progress in cold climates than in warm. The latter would appear to be the more logical premise because there is less light in northern climates and more need to have the fire indoors, thus making it necessary to let smoke out through windows.

In any event, the window was here to stay and its three basic functions of lighting, insulation and ventilation haven't changed since the first window was whittled out of a wall, be it clay, wood or ice. When the window came into its own, it seemed to “shed light on itself” and gradually became a thing of beauty as well as a functional item.

The sash window came into popularity about the last quarter of the seventeenth century when it replaced the casement window. It still is popular today.

Window Types

Double-hung and casement windows are the two most common styles found in houses. In new construction, the horizontal sliding window and the clerestory (also clearstory) window, a window placed high in the wall or in the ceiling, also is gaining popularity. There are, in addition, a variety of other window styles, each with its own advantages and disadvantages (see Figures 7.8 and 7.9).


FIGURE 7.8 Window Operation


FIGURE 7.9 Window Construction

The double-hung window consists of two sashes that move up and down in a pair of channels. The old colonial type was held up by metal or wood fittings that projected through the rail or stile into holes in the sash. Many houses built prior to World War II (and some built after as well) have sashes that are connected by a cord or chain to a center balance weight that's hung inside the wall. Modern double-hung windows are held open by tension springs.

The advantage of a double-hung window is that it offers two perfectly flat surfaces at all times, with storm windows and screens on the outside and any type of blind, curtain or drape on the inside. One disadvantage is that only half of the window can be opened at any one time. Another disadvantage is the difficulty of cleaning double-hung windows from the inside. The newest models have spring-release devices that permit the window to be removed from the inside for cleaning.

The casement window consists of one or more sashes hinged at the side like a door, swinging horizontally out or in, usually with the aid of a crank. Its advantages are that it's very easy to wash and it provides 100-percent ventilation. The disadvantages are that it usually does not fit tightly, drafts result and ugly screens and storm windows must be placed on the inside. The newest models have improved on tightness and have made the appearance of screens and storm windows less objectionable.

The horizontal sliding (traverse) window is like a double-hung window laid on its side. It consists of two sashes that slide back and forth. The outside is somewhat easier to clean than a double-hung window and it has the further advantage of not interfering with storm windows and screens on the outside and blinds, curtains or drapes hung on the inside. Additional advantages are extra privacy and safety for children when the window is set high in the wall. If the window is set high, additional furniture can be placed along the wall. The principal disadvantages are its appearance, which does not blend with many traditional designs, its tendency to stick if there is any settling of the wall or damage to the window and the fact that it permits only 50-percent ventilation.

The jalousie window is popular in warm climates, where it permits up to 100-percent or controlled ventilation of a large wall area. It is designed like a Venetian blind with slat-like glass panes that open and close with a cranking device. The disadvantage is that the many small panes are difficult to clean and tend to leak.

Awning windows open up and out, usually by means of a cranking device. They have the advantages of keeping out rain when in an open position and providing 100-percent ventilation. Their disadvantage is that storm windows and screens must be placed on the inside.

A hopper window is like an awning window hung upside down and backwards. It opens into the room and is hinged from the bottom. Its ad vantage is that it directs the incoming wind upward. Its disadvantage is that it interferes with curtains, drapes and blinds and often presents a safety hazard because it protrudes into the room.

The basement transom window is like a hopper window except it's hinged at the top. Its advantage is that it directs the air downward from its customary high location on the basement wall. A disadvantage is that it provides little rain protection and it also tends to leak.

Weather-Stripping

The purpose of weather-stripping on windows is to provide a seal to pre vent air and dust leakage. A common kind of weather-stripping used to day is the spring-tension type of bronze, aluminum, rigid vinyl, stainless or galvanized steel or rigid plastic steel. Other types are woven felt, compression sash guides and compression bulbs.

Storm Windows and Screens

Most windows transmit heat and cold far in excess of a typical house wall. Heat loss and transmission may be reduced by using storm windows that often are made in conjunction with screens. In cold weather, they save enough fuel to justify their expense and inconvenience, which vary with the house construction, climate and habits of the people in the house. Although the advantage of storm windows is that they reduce drafts, they are difficult to clean and are considered by many to be unattractive.

Hardware

The purpose of window hardware is to provide effective closure, to operate the sash and to hold it stationary in an open position. Window hard ware may be a simple lock or a complex opening and closing device. Many double-hung windows still are equipped with balancing weights and hardware.

Installation

To perform satisfactorily, a window must be properly installed. Because windows often are damaged in shipment prior to installation, they should be checked for squareness and equal spacing to the jambs. Braces often are used to hold the window in shape until after installation. The frame is fitted to the opening and shims are used to support the frame while it's being nailed into place. After the frame is nailed to the rough frame, the space between it and the rough frame is filled with insulation, flashing is installed and the entire unit is caulked. Hardware and weather-stripping are installed and adjusted for proper operation. Interior trim then is nailed in place to seal the wall cavity between the rough frame and the finish frame. All wood windows should be prime-coated as soon as they arrive on the site if they haven't been factory-primed.

Defective Windows

Dust streaks or water stains around the window trim can be evidence of leakage.

While checking windows, some with missing locks and window lifts or counterbalance weights may be discovered. It also may be difficult to reach over the kitchen sink to open that window if it's the double-hung type. A window in the bathroom over the tub or toilet lets in uncomfortable drafts.

A special look should be taken at the windows in children’s rooms. Are they high enough to be safe yet low enough to allow escape in the event of a fire?

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