1. b.      Is Concrete not the stones?

Concrete is one of the oldest building materials, having been used by the Romans as early as 100 B.C. Concrete is a mixture of cement, sand, coarse and fine aggregates, admixtures, and water. When first mixed, it is plastic (able to flow and be shaped) and can be cast to take the shape of the formwork provided.

Hardening of the concrete is caused by a chemical reaction between the cement and water called hydration. Most mixtures of concrete set within 4–12 hours, depending on the temperature, the volume of the pour, type of cement, and admixtures. When the temperature is below 70°F (20°C), the reaction slows. Very little chemical reaction takes place below 40°F (4°C), and almost none occurs at 32°F (0°C). The rule of thumb is: if you are comfortable, the concrete is comfortable. Concrete continues to harden for months after the initial set, but most placements reach their compressive or design strength within 28 days. Forms can be removed after one to several days or when the concrete can support itself. This should be determined by an engineer.

Why are prices of Cement different?

Cement binds the concrete mix together. There are a number of types of cement. The most common, used for general construction, is called Type I Normal Portland cement. Another variation used in construction is white Portland cement. It is light-colored and used chiefly for architectural effects. White Portland cement is made from carefully selected raw materials and develops the same strength as the normal gray-colored Portland cement.

 

1. e.      Are there types and differences in strength etc?

Types of cement include:

• Type I, Normal Cement (most common)

• Type II, Moderate Sulfate Resistance (slow-reacting)

• Type III, High Early Strength (fast-setting)

• Type IV, Low Heat of Hydration (low heat generation)

• Type V, High Sulfate Resistance

These other types of cements, along with aggregates and admixtures, are available to produce special types of concrete. Type IV is low heat generation for large construction building foundation projects, such as dams. Others have high early strength to produce concrete that sets faster than normal, permitting earlier form removal and thus speeding construction. Still others are more resistant to deterioration caused by sulfates and alkalis in the soil.

 

1. f.        What is Concrete Mixes?

A concrete mix should be designed to produce the desired result. Characteristics and properties of concrete depend on the materials, and their proportions, that make up the mixture.

This will determine the workability, strength, durability, economy, volume stability, and appearance of the finished hardened concrete. Enough water is added to make the mix plastic, so that it will flow into the forms. Too much water, however, will reduce the strength and durability of the concrete, so the contractor needs to be careful. A typical mix would consist of 10% cement, 15% water, 25% fine aggregates, 45% coarse aggregates, and 1% to 5% entrained or entrapped air.

Any material added to the concrete mix — other than cement, sand, aggregate, and water — is known as an admixture. Admixtures are used to make the mix more workable, retard or speed up hardening, increase freeze resistance, or increase chemical resistance. Common admixtures to concrete include air-entrainment, used to improve durability in freeze/thaw environments; retarders, used to slow down the initial set of fresh concrete, especially in hot weather; accelerators, used to speed up the initial set of fresh concrete in cold weather; water reducers, used to reduce the amount of water required for a desired workability and water-to-cement ratio for strength, and coloring agents, used for altering the color of the concrete mixture. Concrete is typically transported to the jobsite in a ready-mix truck.

1. g.      What is Reinforced Concrete? Is it not a waste of money and materials?

Concrete has great compressive strength, but very little tensile (pulling) strength. To overcome this weakness, concrete is cast around steel reinforcing bars. These bars (commonly referred to as “rebar”) have high tensile strength. As the concrete hardens, it grips the steel to form a bond. The size of the bar is indicated by the bar number, which is a multiple of 1/8″. For example, a #4 bar is 1/2″in diameter (4 × 1/8″= 1/2″).

Reinforcing bars are round in shape, with projections (called deformations) formed in the rolling process to strength bonding with the concrete. Bars are placed after the forms are constructed. The concrete is then cast around the bars.

Sheets of wire mesh also are used for reinforcement.

1. h.      What is Welded wire fabric (WWF)in concrete?

This is a prefabricated material used to reinforce concrete slabs, floors, and pipe. It consists of a mesh of steel wires welded together.

It is available in sheets and rolls.

There are two types of welded wire fabric: smooth (or plain), designated by a W; and deformed, designated D. The “D” fabric has deformations along the wire to better develop anchorage in the concrete. Previously, the fabric was specified by gage number, and some drawings still use this system.

Welded wire fabric is further designated by numbers.

An example is 6×8–W8.0×W4.0. The first number (6) gives the spacing of the longitudinal wire in inches. The second number (8) gives the spacing of the transverse wires in inches. The first letter-number combination (W8.0) gives the type and size of the longitudinal wire. The second combination (W4.0) gives information on the transverse wire.

In the example given, the longitudinal wires are 6″ apart. The transverse wires are 8″ apart.

The longitudinal wire is smooth and has a cross sectional area of 0.08 in2. The transverse wire is also smooth with an area of 0.04 in2. 

1. i.        What are Masonry accessories and its use in construction business?

Masonry structures are made from a number of smaller units held together with a bonding material known as mortar. Masonry units are manufactured as brick, concrete block, stone and clay tile. Mortar is a cementitious material that bonds the individual units together.[5]

Almost all masonry construction must be reinforced with metals. Like concrete, masonry has good compressive strength and poor tensile strength.[6]

 

        i.            Brick Masonry

Brick masonry uses units (bricks) that are manufactured, rather than removed from quarries.

There are many types:

• Adobe brick.

Natural sun-dried clays or earth and a binder

• Kiln-burned brick.

Natural clays or shales (sometimes with other materials added, such as coloring) molded to shape, dried, and fired for hardness.

• Sand-lime brick.

A mixture of sand and lime; molded and hardened under steam pressure and heat.

• Concrete brick.

A mixture of Portland cement and aggregates molded into solid or cored units and hardened chemically.

There are many types and sizes of brick. Most are either building brick or face brick. Some special types are used to a lesser extent.

• Building brick. Usually called “common brick,” this is the most-used type. It is used for walls, backing, and other applications where appearance is not important.

• Face brick. This material is manufactured under more controlled conditions to produce bricks of specific dimensions, colors, and structural qualities. Face bricks are more expensive than building bricks, because of the care going into their manufacture. Face bricks with defects are often sold as common bricks.

• Glazed brick. Finished with a hard, smooth coating, these bricks are used for decorative and special service applications.

• Firebrick. Used where masonry units are subjected to extreme heat, such as fireplaces, incinerators, and industrial furnaces.

• Paving brick. Used in driveways or areas where abrasion is a concern.

Special bricks also are available in unusual shapes for window sills, rounded corners, and other nonstandard applications.

Brick Symbols

Brick is indicated on plan and section drawings with 45° crosshatch lines. For common brick, the lines are widely-spaced; for face brick, the spacing is narrower.  Firebrick is shown on plan drawings with the usual 45° lines indicating brick, plus vertical lines that designate it as firebrick.

On elevation drawings, brick is normally indicated by horizontal lines. A note identifies the type of brick. Some architects only draw horizontal lines around the outer surface of brick walls.

 

What is Brick Bonds?

There are several types of brick bonds, so construction workers should be familiar with those used most widely. A bond is the bricklaying pattern. Bonds are designed to improve appearance, add strength, or tie a Wythe wall to a backing wall.

The bonds used most widely are common bond, running bond, English bond, English cross-bond, Flemish bond, and stacked bond.

 

My builder is making different Brick Positions? Can bricks be positioned in different ways?

These positions are used by the architect to develop a design or style in the building, as well as to add to the structural strength of the brickwork. Each position has a name that identifies it.

For example, the most common position is the stretcher.

It is laid in a flat position, lengthwise with the wall. Bricks in the stretcher position make up a large portion of most walls.

In some bonds, such as the common bond (also called American bond), every sixth or seventh course is turned 90°. This is done to improve appearance or to tie the face brick with the backing wall. Bricks laid in this manner are called headers, and the course is referred to as a header course.

What is Brick Lay-up?

Brick walls can be laid up as single-Wythe walls that are 8″ or more in thickness. These can be solid or have two or more cells (spaces) in them. Sometimes the cells of the brick are filled with granular insulation.

What is Concrete Masonry Units (CMU)?

Another popular and widely used building material is the concrete masonry unit, which is formed from Portland cement, sand, and gravel.

By using different aggregates, such as sand, gravel, expanded shale, and pumice, the manufacturer can control the weight, strength, and acoustical properties of the CMU.

CMUs are made in a variety of sizes, shapes, and densities to meet specific construction needs. The most popular is the standard block, with dimensions of 7 5/8″×7 5/8″×15-5/8″. When

3/8″ of mortar is used; this becomes an 8″×8″×16″ module. Another common block size is the 3 5/8″×7 5/8″×15-5/8″

What is Concrete Block Symbols?

Symbols for concrete block in plan and section views are the same as concrete with the addition of lines crosswise of the run. The elevation view symbol for concrete block is the same as poured concrete with lines added to represent the block pattern.

Concrete block can have colored surfaces and special design features. Slump blocks give the appearance of rough adobe brick.

Tell me more about Stone Masonry?

The most common materials used in stone masonry are granite, limestone, marble, sandstone, and slate. Like concrete, stone has been used as a building material for many centuries. In the past, stones were used for structural members, roofing, and finishing. Due to the development of new materials and methods of construction, stones are now used mainly for their decorative value.

Most stones are removed from a quarry and sent to a finishing mill for final dressing. Some stones are used in their original shapes and surface finishes. Others are cut to a specific shape, size, and finish. These are known as cut stones.

Stone masonry can be laid as solid walls of stone or as composite walls backed with concrete block or tile. It is also used as a veneer. Stone walls are classified according to shape and surface finish of the stone, such as rubble, ashlars, and cut stone.

My builder says he needs ruble? What is ruble?

Rubble consists of stones as they come from the quarry or are gathered from a field or stream.

Such stones may be smooth with rounded edges or may be rough and angular. The random rubble wall consists of stones laid in an irregular pattern with varying sizes and shapes. Other rubble patterns are coursed, mosaic, and strip.

What is Ashlars stones?

Ashlars stones are squared stones that have been laid in a pattern but not cut to dimensions.

There are several ashlars patterns:

• Regular: Uniform continuous height.

• Stacked: Tends to form columns.

• Broken range: Squared stones of different sizes laid in uniform courses, but broken range within a course.

• Random range: Neither course nor range remain uniform.

• Random ashlars: Course is not uniform and ends are broken, not square.

Cut stones, also known as dimensional stones, are cut and finished at the mill to meet the specifications of a particular construction job.

Each stone is numbered for location. Unlike ashlars masonry, which is laid largely at the design of the mason, cut stones are laid according to the design of the architect.[10]

 

Structural Clay Tile

Structural clay tile is made of materials similar to brick, but it is a larger building unit. It has many uses in construction — as load-bearing walls, backup for curtain walls, and fireproofing around structural steel. Rectangular open cells pass through each unit, and tile comes in a variety of shapes and sizes.

Clay tile has largely been replaced with hollow brick and concrete masonry units. Most masonry walls today are composite walls of a finish surface material and a less expensive backup material.

Terra cotta is a type of structural clay tile principally used for nonbearing ornamental and decorative effects.

 

Gypsum Blocks

Gypsum masonry blocks are used primarily for interior nonbearing walls, fire-resistant partitions, and enclosures around structural steel. Made from gypsum and a binder of vegetable fiber or wood chips, they can be given a plaster finish coat.

Gypsum blocks have a face size of 12″ × 30″ and come in thicknesses of 2″, 3″, 4″, and 6″.

Is Mortar supposed to be the same mixture value throughout the building process?

Mortar is the binding agent used to hold masonry units together. Mortar also compensates for the differences in brick and stone sizes.

Metal ties and reinforcement are secured in mortar. Mortar consists of cement, hydrated lime, sand, and water.

The American Society for Testing and Materials has established standards for mortar. There are five different standardized types:

• Type M has high compressive strength and good durability. It is used for unreinforced underground masonry.

• Type S is also a high-strength mortar. Although its compressive strength is not as high as Type M, it has a stronger bond and greater lateral strength. It also has the greatest tensile strength of any mortar type.

Type S is used for reinforced masonry, unreinforced masonry subjected to bending, and in situations where mortar is the only connection between face brick and backing brick.

• Type N is a medium-strength, general-use mortar. It is best used for exposed, aboveground masonry.

• Type O is low-strength mortar used for interior, nonbearing masonry. This type of mortar should not be used in applications that will be exposed to freezing temperatures.

• Type K has very low strength and should only be used for interior applications when strength is not a concern.

Stone work usually requires a special type of mortar consisting of white Portland cement, hydrated lime, and sand. This mortar prevents stains caused by ordinary cements. Mortar in the joints is normally raked back from the surface as the stone is set. Later, the joint is pointed, using the same mortar or a colored sealant.

Trade associations recommend proportions of cement, hydrated lime, and sand for mortar.

Local building codes also set allowable limits. A typical mixture would be 1 part Portland cement by volume, one-fourth part hydrated lime, and 3 parts sand. Water is added as needed to make the mortar workable. Many brick masons use a special masonry cement containing plasticizing agents to make the mortar more workable.

 

What are Masonry Accessories?

Besides the masonry units and mortar, additional details are needed in masonry construction.

Bond beams, joints, lintels, and flashing are needed to complete a wall.

        I.            Bond Beams

Concrete masonry walls are usually reinforced horizontally and vertically by constructing a reinforced beam or column within the wall. This is done by pouring grout (a flow able mixture of sand and cement) around reinforcing steel inserted in the units.

Special channel blocks are used to form the horizontal bond beams, using reinforcing steel and mortar or grout. Vertical pilasters or bond beams are formed by inserting reinforcing bars in a vertical cell after the wall is laid, then filling the cell with grout. Bond beams are typically used over masonry wall openings such as windows and doors, the top of walls or anywhere that additional strength is required in the wall construction.

      II.            Lintels

Lintels are members placed in masonry walls above door and window openings. Lintels are supported on either side of the opening. They can be made of precast concrete, steel, or other materials. The door and window schedule will often include the size and type of lintel used.

    III.            Masonry Joint Reinforcement

Masonry walls are reinforced by placing various anchors, ties, and rods in the mortar joints. These reinforcing units are produced in many sizes and shapes for different applications.

Reinforcing devices are called out directly on the prints or in applicable building codes.

 

Can you tell me the use of Metals in building?

Metal is used extensively in the construction industry. Large commercial buildings use structural steel. Construction jobs make use of metal windows, doors, studs, beams, joists, wall facings, roofing, plumbing, and hardware.

Kinds of Metals

Metals can be divided into two categories, ferrous and nonferrous. Ferrous metals contain iron as a principal element, and usually have magnetic properties. They typically have more strength than nonferrous metals. Nonferrous metals contain no iron and do not have magnetic properties. They are typically lighter and less strong than ferrous metals.

a.     Ferrous Metals

Iron

Iron is malleable, ductile, magnetic, and silver white in color. There are many kinds of iron, such as pig iron, cast iron, and wrought iron. Iron is one of the principal ingredients of steel.

Steel

An iron-based alloy with a carbon content ranging from 0.2% to 2.0% Depending on the intended use, steel has many chemical compositions. Carbon steel, alloy steel, mild steel, medium steel, tool steel, spring steel, and stainless steel are a few of the varieties available. By varying the carbon content, steel can be made harder and stronger, but it also becomes more brittle. Adding chromium, nickel, and magnesium will make the metal highly resistant to corrosion.

b.Nonferrous Metals

Aluminum

Pure aluminum and aluminum alloys are used in many building applications where resistance to corrosion is important. Aluminum that is 99% pure is soft and ductile, but weak. Aluminum is typically used in such building applications as flashing, downspouts, some kinds of roofing, doors and trim, mullions for windows, etc. Aluminum also is made as an alloy with copper added for strength and casting uniformity. Aluminum alloys are made in structural shapes for use as H-beams, I-beams, and angles. Aluminum is also used for some ductwork, screens, and electrical wiring.

Copper

Copper and copper alloys have a high electrical conductivity and are resistant to corrosion. This metal is typically used in construction for water distribution, electrical wiring, and flashing. The particular metal would be indicated on the drawing as a note and most likely detailed in the specifications.

Brass

This metal is widely used for door and window hardware, trim, grilles, and railings. Brass is copper with zinc as its principal alloy element.

Bronze

A copper-tin alloy, bronze also can contain various other elements, such as aluminum or silicon. Bronze resists corrosion and is widely used for ornamental architectural products.

 

What is Surface Treatments in metals used when building?

Metals used in construction may have protective or decorative surface treatments applied to them. Treatments include:

• Chroming

Chromium applied as a finish to a metal surface.

• Galvanizing

Coating steel or iron with zinc to resist rusting. Galvanized iron is widely used for flashing and other applications where weather tends to corrode metals.

• Rusting

Certain steels are designed to form a protective layer of rust, a reddish-brown surface coating formed when the metal is exposed to moisture and air.

• Electroplating

An adherent metallic coating deposited by electrolysis; Electrolysis is a process that uses electrical current to migrate positively- and negatively-charged ions from electrodes to the metal product.[13]

 

Why am I hearing from my building contractor "Metal Gages"?

Metal materials less than 1/4″ in thickness (often called “sheet metal”) are classified in the gage system, gages typically range from 4 (thickest) to 38 (thinnest).

For example, 4-gage metal has a thickness of 0.224″, a little less than 1/4″, while 22-gage metal is 0.0299″ (approximately 1/32″).

Wall studs, lintels, window and door frames, and floor joists are made from heavy-gage metals.

Thin-gage metals are used for such items as roof flashing, duct work, roofing, and wall siding.

 

Steel in Construction

Steel is the most widely used metal in construction, with applications ranging from structural support to reinforcement to decorative uses.

Structural steel is the term applied to hot-rolled steel sections, shapes, and plates.

This includes bolts, rivets, and bracing.

Structural steel shapes are formed by passing heated strips of steel through a succession of rollers that gradually form the metal into the required shape. Structural steel shapes are available in a number of sizes and weights.

 

A typical designation for a wide-flange beam would be W12×16, which indicates a beam 12″ in-depth that weights 16 pounds per linear foot. A typical designation for a lightweight beam, sometimes called an I-beam, would be S8×23. This indicates that the beam is 8″ deep and weighs 23 pounds per linear foot.

Steel members are connected to form building frames. The frame is usually then hidden behind other materials, such as a masonry wall, precast panels, or sheet metal siding.

Steel angles (sometimes called angle iron) are used as bracing in steel framing and to construct open-web joists.

Angles are designated with the letter “L,” followed by the lengths and thickness of the “legs.” For an angle identified as L3×3×1/2, both legs are 3″ long and 1/2″ thick.

6.      Whats the use of Wood and Plastics in building?

Wood continues to be one of the chief building materials.

It is used for structural framing (rough carpentry), trim, floors, walls, and cabinetry (finish carpentry and architectural woodwork). Relative to its weight, wood has high strength in compression, tension, and bending. It also has excellent impact resistance.

While steps have been taken to substitute other materials, wood remains a valuable and widely used residential construction material.

Some steel frames are designed to support the entire weight of the building.

Open-web steel joists combine strength with light weight.

Wood Classification

Woods are broadly classified as either hardwoods or softwoods. There are many varieties used for construction. These classifications are not an exact measure of hardness or softness (because this varies) but a general classification based on type of tree. In addition to hardness or softness, woods vary in strength, weight, texture, workability, and cost. Building specifications usually indicate the type and grade of lumber to be used in different parts of the construction.

Lumber

When wood is cut into pieces of specific thickness, width, and length, it is called lumber. Lumber products include rough framing members (at least 2″ thick), such as beams, headers, and posts; finished lumber, such as flooring, door and window trim, paneling, and moldings; and specialty items, such as decorative panels, carved doors, ornamental overlay designs, and turned balusters (stair rail posts).

Lumber is classified as rough-sawn or surfaced to size.

Rough-sawn lumber has been cut to size but not dressed or surfaced.

Surfaced lumber has been dressed or finished to size by running it through a planer. The designation “S2S” is used for lumber dressed on two sides, and “S4S” for lumber that is surfaced or planed on all four sides.

Plywood is a wood product made of several layers of lumber arranged with the grain at right angles in each successive layer and bonded with an adhesive. An odd number of layers-is used so that the grain of the face and back are running in the same direction. The panels are usually 4′ × 8′ in size, and are available in finished thicknesses ranging from 1/8″ to over 1″. Because of its modular size and uniformity, plywood speeds construction and is considered an economical building material.

Interior plywood is bonded with an adhesive that is water-resistant. It is used for cabinetry, rough flooring, and finished walls. Exterior or structural plywood is bonded with a waterproof adhesive. It is used for wall sheathing, finished walls, roof sheathing, and concrete forms.

Glue-laminated Timber

The process of laminating (bonding layers of lumber together with adhesive) has made it possible to span larger distances and change traditional construction techniques. Wood beams, arches, and other members of nearly any size and shape can be fabricated. These laminated products are made of kiln-dried lumber and prepared for interior and exterior use. These beams are usually prefinished at the factory and delivered to the job with protective wrapping.

9.     What is Finishings in building?

Finishes are the visible surfaces of a building, such as gypsum wallboard, paint or wallpaper, ceramic tile, carpeting, wood flooring, and acoustical ceilings. Finishes are, in part, delineated on the drawings and specified in a room finish schedule.

Gypsum Wallboard and Plaster

Gypsum wallboard and plaster products consist of a core of air-entrained gypsum between two layers of treated paper. Wallboard comes in standard 4′ × 8′ sheets, but is available in 4′ × 9′ and 4′ × 12′. If ordered in truckload quantities, almost any special size desired can be produced.

Wallboard is fastened to wood or metal studs with nails or screws, and varies in thickness from 1/4″ to 1″. Joints are sealed with a joint compound and paper tape to provide a smooth, even surface.

The wall can be painted, papered, or given a surface texture to enhance its appearance.

Lath for gypsum plaster walls is available in 16″ × 48″ sheets with thicknesses of 3/8″ and 1/2″. The lath is fastened to the studs and a three-coat gypsum plaster finish — scratch coat, brown coat, and finish coat — is applied.

Building papers are available in a variety of types suitable for sheathing walls and roofs.

Some papers are reinforced for strength and tear resistance. Building papers are treated with asphalt, plastic, tar, or other materials. The building paper is usually specified on the print or in the specifications.