Chapter 4, Unit 11: Construction

Foundation Walls

-The foundation wall sits on top of the footing and is usually about 8 inches wide and made of poured concrete or concrete blocks. If the area between the foundation walls has been excavated deeply enough to provide head room, then a basement has been created. If the foundation area is only partially excavated, then what results is called a crawl space. -The National Building Code requires that the foundation wall of a basement or crawl space and floors that come in contact with soil be treated for ground and surface water seepage by the placement of a vapor barrier. A vapor barrier is most often a plastic sheet that keeps moisture from passing through a wall. In addition, the local code may require that the vapor barrier and/or the area beneath be treated for termites. This requirement is dependent on local conditions.

Wood Framing

-Wood framing refers to the framework of the structure. The exterior framing must be large enough and strong enough to support floor and roof loads. The walls must also resist lateral wind loads and, in some locations, earthquake forces. -The pieces of wood that are used in this framing are called studs. Studs in exterior walls of one and two-story buildings are at least 2x4 inches with the 4-inch dimension forming the basic wall thickness. Stud spacing is normally 16 inches in exterior walls, although 24-inch spacing of 2x4 studs is acceptable in one-story buildings if wall sheathing or siding is of adequate thickness to bridge across studs. In three-story buildings, studs in the bottom story are at least a nominal 3x4 or 2x6 inches and may not exceed 16-inch spacing. Studs are arranged in multiples at corners and partition intersections to provide for rigid attachment of sheathing, siding and interior wall finish materials. -These same size studs when used horizontally to frame floors and ceilings are called joists. Studs used to frame the roofing system are called rafters.

Sill Plate

-A sill plate is a wooden support member that is laid on top of and bolted to the foundation wall. This sill plate serves as the base for the wall framing. The sill plates are the first part of the frame to be set in place. -The floors of the building are supported by a series of joists. The distance between an opposing pair of outside walls is usually too great to be spanned by just one joist. So when two or more joists are required to cover the span, support is provided for the joist ends by girders or support beams. These beams or girders can be made of steel or can be several wooden members fastened together. Sometimes the main floor beam of the structure is supported by lally columns. These are steel cylinders filled with concrete. The lally columns are placed in the crawl space or basement and adjusted to the correct height. Their spacing is determined by the size and material of the main floor beam.

Amperage

-Amperage is measured in amperes which can then be converted into watts or kilowatts to determine the amount needed in the electric capacity for usage projected for the building. -If the wire size or service is not strong enough for the building's needs, the circuits can overheat, resulting in blown fuses or tripped circuit breakers. A fuse is a protective device containing a wire that melts and breaks the circuit when the current exceeds a certain value. Melted or "blown" fuses can be replaced with new ones. A circuit breaker is an automatic switch that stops the flow of electric current in a suddenly overloaded or otherwise abnormally stressed electric circuit. Circuit breakers "trip." Unlike fuses, they don't need to be replaced, just reset. -The panel where the fuses or circuit breakers are located may have an amperage rating written on it. However, the only sure way to know the service size is by looking at the service entrance cables for a size indication. The number of fuses or circuit breakers is not an indicator of size, although each fuse or breaker can be identified as to the number of amps it can carry. This rating is specified in the National Electric Code.

Standards

-Before beginning any construction project, a contractor or developer must comply with all of the applicable federal, state, county, and local regulations. Federal Standards, Laws, and Regulations -If a property is built with any money from a federal program, such as the Veterans Administration (VA) or the Federal Housing Administration (FHA), the property must be approved in advance and be inspected by the proper agency as the construction progresses. -Federal laws and regulations include: 1. The Minimum Property Standards (MPS), which is a set of HUD regulations, establish certain minimum standards for buildings constructed under HUD housing programs. This includes new single family homes, multi-family housing and health care type facilities. 2. Interstate Land Sale Full Disclosure Act - This program protects consumers from fraud and abuse in the sale or lease of land. In 1968 Congress enacted the Interstate Land Sales Full Disclosure Act, which is patterned after the Securities Law of 1933 and requires land developers to register subdivisions of 100 or more non-exempt lots with HUD and to provide each purchaser with a disclosure document called a Property Report. The Property Report contains relevant information about the subdivision and must be delivered to each purchaser before the signing of the contract or agreement. 3. National Electric Code - The National Electrical Code (NEC) is a United States standard for the safe installation of electrical wiring and equipment. It offers minimal guidelines and standards. It is part of the National Fire Codes series published by the National Fire Protection Association (NFPA). While the NEC is not itself a U.S. law, NEC use is commonly mandated by state or local law. 4. Americans with Disabilities Act - ADA mandates that persons with disabilities have equal access to jobs, public accommodations, government services, public transportation and telecommunications. It prohibits discrimination in the "full and equal enjoyment of goods and services" provided by public places, including hotels, shopping centers and offices, and it applies to the lease and operation of commercial facilities. If a contractor is planning to build a new facility or modify an existing one, he or she needs to consult the ADA Standards for the specific requirements. Renovations or modifications are considered to be alterations when they affect the usability of the space; for example, installing a new display counter, replacing fixtures or flooring, or replacing an entry door. However, simple maintenance, such as repainting a wall, is not considered an alteration by the ADA. ADA also requires new multi-family housing that has at least four units to be easily accessible for the disabled and elderly. ADA is enforced by the United States Attorney General. Violation can incur penalties of injunctions against the operation of a business, up to $50,000 in fines for the first offense, and $100,000 for successive violations. NOTE: Many communities also have State or local accessibility codes enforced by local building inspectors. When a local accessibility code exists, the owner must follow both the code and the ADA requirements

Air Conditioning Systems

-Central air conditioning and HVAC systems are now common in new construction. Most air conditioning units are situated outside the building, either near a wall or on the roof. However, in some instances, the unit is located in the basement of the structure. -Air conditioning systems are combined with forced-air heating units to deliver heat through the ductwork system in cold seasons and cool, dehumidified air for air conditioning through the same ducts during warm seasons. -The air-conditioning unit pumps liquid refrigerant (a liquid that cools something) into the air-handling unit (AHU), the unit inside the home that generates heated or cooled air. The most common refrigerant used in air conditioners is Freon. The AHU generates cool air and forces it through the home through the ductwork and into rooms. The ductwork system also returns air from the rooms back into the AHU for re-circulation. Meanwhile, the slightly warmed refrigerant travels back outside to the air conditioner, to be cooled and re-circulated. -Air-cooled systems use air as the condensing medium and have a fan that moves the air over the coils. Water-cooled systems use water as the condensing medium and use a pump to circulate the water through the condenser and out to a cooling tower. -Most central air conditioning units can be expected to last about 15-20 years. However this number may be affected by the climate in the geographical location of the unit. For example, a central air conditioning unit in Florida probably has a life expectancy of closer to 10 years.

County and Local Standards, Laws and Regulations

-Cities, counties and local governments have the power to impose their own land use regulations and building codes. These laws may not be in opposition to any federal or state laws; however, they can be more restrictive. -Local laws tend to cover those issues that are specific to the area and are enforced by local agencies, such as planning boards and local building code departments. Any legal matters that arise are handled by the local courts.

Environmental Regulation

-Construction is also subject to environmental regulations. Most legislation is overseen by the Environmental Protection Agency (EPA). Applicable legislation includes the following: 1. National Environmental Policy Act of 1969 -This act requires that an environmental impact statement be filed with the appropriate state or local agency before implementing any new construction or development. This procedure helps to ensure that the proposed project will not have a negative impact on the environment. -Other regulations cover waste disposal, soil and water contamination, air quality, lead treatment, mold, toxic building materials, and radon treatment. Refer to the unit on Land Use Control and Regulation for more details.

Heat Pumps

-For climates with moderate heating and cooling needs, heat pumps offer an energy-efficient alternative to furnaces and air conditioners. Like a refrigerator, heat pumps use electricity to move heat from a cool space into a warm space, making the cool space cooler and the warm space warmer. During the heating season, heat pumps move heat from the cool outdoors into the warm house. During the cooling season, heat pumps move heat from the cool house into the warm outdoors. Because they move heat rather than generate heat, heat pumps can provide up to 4 times the amount of energy they consume. -The most common type of heat pump is the air-source (air-to-air) heat pump, which transfers heat between the building and the outside air. Higher efficiencies are achieved with geothermal (ground-source or water-source) heat pumps, which transfer heat between the building and the ground or a nearby water source.

Sanitary Waste

-In spite of the trend toward public sewerage systems, individual household sewage treatment systems are still the only method of sewage treatment available in many areas. Properly-designed, constructed, and maintained sewage treatment systems minimize the possibility of disease transmission and potential for contamination of ground and surface waters. Soil percolation must be adequate for absorption and land area must be sufficient for the necessary leach field. -A septic system is an onsite system designed to treat and dispose of domestic sewage. It is used when a sewer line is not available to carry wastes to a sewage treatment plant. -The individual parts of the system are the septic tank, a distribution box, and a leach field. Bacterial action takes place in the septic tank where the end products are mainly water, gases, and undigested material, called sludge that sinks to the bottom of the tank and scum that floats to the top of the tank. The septic tank contains baffles that prevent any scum that floats to the surface and sludge that settles to the bottom from passing out of the tank. The gases that are generated vent to the atmosphere via the plumbing vent system. -From the septic tank, the segregated and relatively clear liquid flows into a small distribution box where it is then distributed to several perforated pipes. These perforated pipes then deliver the liquid to a large soil surface area, called a leach field, or absorption field, for absorption. The soil also acts as a filter to remove any small amounts of solids that may be carried along with the liquid. The sludge in the bottom of the tank must be periodically pumped out and properly disposed of.

Importance of Basic Construction Knowledge

-It is important for real estate licensees to be knowledgeable about their products for a number of reasons. Perhaps the most basic is to be able to match home buyers with the types of properties they are most likely to be interested in. Construction knowledge also comes into play in assisting sellers with their pricing and marketing decisions and buyers with their offering decisions. -In addition to knowing about a property and its neighborhood location, it is essential that a licensee take note of the specifics of any property that he or she lists, including such things as: The roof Cracks or chips in the exterior finish The condition of any masonry - chimney, foundation, patio Any broken windows or doors Type of heating and cooling systems Septic tank or sewer Type of water supply - well, cistern, municipal or private -Noting the home condition does not give the agent license to make judgments about the soundness of the structures. If customers ask for opinions, the licensee should refer them to a professional for answers. A general knowledge of construction standards and a community's planning and permitting requirements are also useful in the agent's mission to serve sellers and buyers with competence and expertise. At a minimum, agents are expected, as part of their due diligence, to be familiar enough with zoning and building ordinances to be able to alert a seller or buyer to potential problems.

Wells

-Most municipal areas are supplied by a public water system. This system brings water into homes via a pipe system from a municipal water main or a community well. The water is delivered under pressure and usually has, or should have, cutoff valves at each building and at individual fixtures, so that if a problem arises, it can be repaired without having to turn off the entire system. -Residents in rural areas who do not have access to public water must depend on private wells for their water supply. A state's Department of Health usually provides guidelines for the construction of such wells. The guidelines include information about the proper location for the well. -Here are a few of the typical guidelines. Wells should be located in an area that: 1. will allow adequate access to the well for inspection, maintenance, repair, renovation, treatment, and testing. 2. is not subject to seasonal flooding or surface water contamination, or it should be constructed in such a way that seasonal floodwater cannot enter the well. 3. is up-grade from any potential or known source of contamination unless property boundaries, site topography, location of structures and accessibility require a different location. The minimum horizontal separation distances from potential sources of contamination are published in a table available from the Department of Health. -The ground surface immediately surrounding the well casing should be graded in such a way as to divert surface water away from the well. Concrete should not be used for grading purposes.

Roof Framing

-Roof construction must be strong enough to withstand anticipated snow and wind loads. Framing members must be securely fastened to each other, to sheathing and to exterior walls to enable the roof system to serve as a structural unit. -A rafter is a structural member which supports the roof of the building. Carpenters build rafters to frame the pitch or slope of the roof. The roof ridge beam is the highest part of the frame and forms the top line of the roof. The rafters are attached to the ridge beam at the peak of the roof. -The roof sheathing is made up of wood structural panels or 1-inch board lumber which provides a solid base for roof coverings. Structural panels are manufactured in various thicknesses and are usually 4'x8' in surface dimension. Recommended spans, spacing between panel edges, and the board thickness are stamped on the panel face. Structural panels are installed with the long dimension perpendicular to rafters and with the panel continuous over two or more spans.

National Electric Code

-The National Electric Code covers the installation of electrical conductors, equipment, and optical fiber cables for the following: 1. Public and private buildings, structures, mobile homes, recreational vehicles, and floating buildings 2. Yards, lots, parking lots, carnivals, and industrial substations 3. Installations of conductors and equipment that connect to the supply of electricity 4. Installations used by the electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings, that are not an integral part of a generating plant, substation, or control center

Wall Finishing

-The high resistance of wood frame construction to hurricane, earthquake and other natural forces is provided when wall sheathing is nailed to the outside edges of exterior wall studs, plates and headers. Wall sheathing includes plywood, particleboard and other structural panels such as wafer-board, oriented-strand board, structural insulation board and one-inch board lumber. This sheathing must be applied in strict accordance with manufacturer's nailing requirements to provide a rigid, yet resilient, wood frame system. Some structural panels function as both sheathing and siding. Siding can also be metal or vinyl. -For interior wall finishing, contractors use plasterboard, wallboard, drywall, or sheetrock.

Voltage and Amperage

-Voltage is a measure of how much pressure the electrons in a circuit are under. Amperage is a measure of the amount of electrons moving through the circuit. For example, when a light is on, there is a voltage across the filament of the bulb that is pushing amperage through the circuit. When the switch is off there is voltage across the switch, but there is no current flowing because it is "blocked" by the switch. -Most of the time you can identify whether an appliance, a tool, or a fixture such as a lamp, is 110 or 220 volts by looking at a tag that is attached to the appliance or fixture. Also, the plugs and receptacles for the two types of voltage are different. In most cases, 110 volt plugs have either two straight prongs or three straight prongs, while 220 plugs have three prongs, one straight and two that are L-shaped.

Wall Framing

-Wall framing refers to both the exterior and interior walls. The wall studs are usually 2 x 4 in size with 16-inch spacing. Those walls that support the ceiling and the roof are called bearing walls. Non-bearing walls are part of the interior framework and do not support the building itself. -The studs are arranged in a row with their bottom ends bearing on a long wooden member called a bottom plate or sole plate and their tops capped with another plate called a top plate. Double top plates are used in load-bearing walls and partitions. The double top plate is sometimes called a flitch beam and is made up of two or more structural timbers bolted together with a steel plate sandwiched between them for added strength. -Headers are required at window and door openings to carry vertical loads across the opening. Headers may be supported by doubled studs or, where the span does not exceed 3 feet, framing anchors may be used with single supporting studs. Headers are also known as lintels. They support the ceiling and the roof over the doors and windows.

Roof Finishing

-When roof rafters are installed, they typically extend beyond the structure walls to form an overhang. The overhangs are called eaves. The eaves are the lowest part of the roof. The contractor then installs a thin impermeable material called flashing to prevent water penetration and/or provide water drainage between the roof and the walls. Flashing is often installed over exterior door openings and windows as well. -The term fascia is used to describe the horizontal "fascia board" which caps the end of rafters outside the building. The fascia can be used to hold the rain gutter. The finished surface below the fascia and rafters is called the soffit.

Slab-on-Grade Construction

-When the ground at a building site is level, the developer can use a slab-on-grade foundation. The slab is probably the easiest foundation to build. It is a flat concrete pad poured directly on the ground. It takes very little site preparation, very little formwork for the concrete and very little labor to create. It works well in warmer climates, but it has problems in the north because the ground freezes in the winter. At worst, this freezing can shift the slab. And it can result in cold floors in the winter. -Around the edge of the slab, the concrete forms a beam that is perhaps 2 feet deep. The rest of the slab is 4 or 6 inches thick. A 4-inch or 6-inch layer of gravel lies beneath the slab. A 4-millimeter sheet of plastic lies between the concrete and the gravel to keep moisture out. Embedded in the concrete is 6-inch by 6-inch wire mesh and steel reinforcing bars. This kind of foundation is often referred to as a floating slab. It "floats" on the soil, with the deeper concrete around the edge holding it in place. In northern climates, the concrete around the edge has to extend deep enough to remain below the frost line in winter.

Wiring Materials

-Wiring runs throughout the structure from the electric panel box through the walls to the outlets. Outlets can be plugs, switches and light fixtures. 1. Aluminum versus Copper- Aluminum wiring is used where the current is the heaviest, usually where the current comes into the building. It is also used for heavy appliances, such as dryers and air conditioners. Aluminum wiring has been known to cause overheating in outlets and switches that are not designed for use with aluminum wire, so older buildings should be inspected to be sure there are no potential wiring problems. Copper wiring does not overheat and it can carry both large and small loads. Most new buildings have copper wire throughout, except at the service entrance where aluminum is still used. 2. BX Cable- BX cable is technically known as armored cable or "AC." It has a flexible aluminum or steel sheath over the conductors and is fairly resistant to damage. 3. Romex Cable- Romex is a brand name for a type of plastic insulated wire, sometimes called non-metallic sheath. The formal name is NM. This cable is suitable for use in dry, protected areas that are not subject to mechanical damage or excessive heat. Most new homes are wired almost exclusively with NM wire. 4. Conduit- A pipe made from plastic, steel or aluminum that is used for protection and routing of electrical wiring, conduit can be used for both above ground and underground applications. 5. Greenfield Conductors- This is a type of flexible metal conduit (FMC) similar to armored cable, except that the conductors are installed by the electrician. With armored cable, the armor is wrapped around the conductors at the factory to form a complete cable assembly. FMC is often referred to as Greenfield after the person who submitted the product for listing in 1902. FMC is not suitable for wet locations and it should not be buried underground or in concrete. It is easy to use and work with in small, confined spaces.

Types of Pipe

1. Cast iron - Used for underground drainage systems because of its strength and sturdiness. It can be lightweight or heavyweight, depending on the application. Iron pipes are very heavy and are prone to rusting on the inside. 2. Galvanized - Used for hot and cold water supply lines. Galvanized steel pipe was commonly used years ago for the water supply lines, but more recently it has been replaced by other types of pipe. Steel is not used for underground plumbing. 3. Copper - Used for both water supply lines and drainage. Copper lasts longer than other metal pipes. It is easy to work with and resists corrosion. Copper is used for both hot and cold water supply lines. Copper pipe can be rigid or flexible, depending on the application. 4. PVC - Used mostly in areas where hard water is a problem. PVC is plastic pipe, so it is very lightweight and inexpensive. Unlike metal pipe, PVC crushes more easily, is less resistant to heat and requires more support because it is so much more flexible than metal. Some municipalities including New York City have restrictions on the use of PVC pipe. 5. Brass - Rarely used in plumbing installations today because of its expense. 6. PEX - Ideally suited for potable water plumbing applications. It is flexible, making it easy to install and service. PEX is able to withstand the high and low temperatures found in plumbing and heating applications, and it is highly resistant to chemicals found in the plumbing environment. PEX is also very resistant to freezing and breaking. PEX systems have fewer joints and are easier to install providing a lower-cost installation over traditional plumbing materials.

Categories of Insulation

1. Loose fill - Includes loose fibers or fiber pellets that are poured or blown into building cavities or attics using special equipment. 2. Batts and blankets - Made of mineral fiber -- either processed fiberglass or rock wool -- and used to insulate below floors, above ceilings, and within walls. 3. Rigid board - Made from fiberglass, polystyrene, or polyurethane and used for work on flat roofs, on basement walls and as perimeter insulation at concrete slab edges, and in cathedral ceilings. 4. Spray foam - Two-part liquid containing a polymer and a foaming agent sprayed through a nozzle into wall, ceiling, and floor cavities. 5. Reflective - A metallic foil material (usually aluminum) designed to block radiant heat transfer across open spaces.

BTU Ratings

A British Thermal Unit (BTU) is the amount of heat energy needed to raise the temperature of one pound of water by one degree F. BTUs measure the amount of heat an air conditioning unit can remove from the room. As the BTU rating increases, so does the size, weight and cost of the unit.

Steam Systems

A steam system delivers steam to radiators or other heating elements where the steam gives up its heat and is condensed back to water. The radiators and steam supply pipes are pitched so that gravity eventually takes this condensed water back down through the steam supply piping to the boiler where it can once again be turned into steam and returned to the radiators.

Insulation

All the materials that are used in construction absorb and transfer heat. Eighty to ninety-five percent of this heat is transferred, from the warmer side to the cooler side by conduction, convection or radiation

Pipe Size

Building codes dictate the minimum pressure (the lowest pressure that will allow the system to operate safely and efficiently) for plumbing fixtures. The codes also dictate the maximum pressure allowed, which is the highest pressure that will not cause damage to the system. Pipes that are too small or those that have a mineral deposit buildup prevent the pressure from moving the water to the fixtures. Pressure regulating valves can reduce and maintain the correct water pressure within the system, while a booster pump can increase the pressure if needed.

Electric Heat

Electric heating in homes is usually in the form of baseboard heaters along the walls of a room, although it can be in the form of a heat pump. Electric heating has several advantages: it can be precisely controlled to allow a consistency of temperature within very narrow limits; it is cleaner than other methods of heating because it does not involve any combustion; it is considered safe because it is protected from overloading by automatic breakers; it is quick to use and to adjust; and it is relatively quiet.

Electric Water Heaters

Electric water heaters are also storage tank units and are very popular because they are inexpensive and easy to install. Electric heat is 100 percent efficient, but the cost per KWH of electricity is more than the cost of using a gas-fired water heater. Electric hot water heaters are also slow to recover as compared with gas-fired water heaters. However, maintenance of the electric water heater is easier as it requires very little maintenance.

Floor Framing

Floor framing consists of a system of sills, girders, joists or floor trusses and sub-flooring that provides support for floor loads and gives lateral support to exterior walls.

Forced Air

Forced air heating is probably the type most commonly installed in North America. The three types of air furnaces are electric, oil-fired, and gas-fired. A forced-air system draws room air through ductwork and a filter into a furnace, where the air is heated. The warmed air is then blown back to rooms through ductwork. The system includes an air filter, blower, heat exchanger/element/coil, and various controls. Like any other kind of central heating system, thermostats are used to control forced air heating systems.

Gas Water Heaters

Gas water heaters are very popular. These units have an insulated tank where water is heated and stored until it is needed. They offer fast recovery times and can offer more economy than electric water heaters. The standing pilot light gas water heater has a pilot light which remains lit 24 hours a day, 7 days a week and consumes gas to stay lit, while a gas-fired water heater with electronic ignition only lights a pilot light when it necessary to fire the main burners.

Hot Water Systems

Hydronics is the name for the use of water as the heat-transfer medium in heating and cooling systems. Some of the oldest and most common examples are steam and hot-water radiators. In any hot water system, the water is heated in a boiler and circulated by means of one or more circulator pumps. A system may be broken up into individual heating zones using either multiple circulator pumps or a single pump and electrically operated zone valves.

Balloon Frame Construction

In balloon-frame construction, exterior wall studs continue through the first and second stories. First floor joists and exterior wall studs both bear on the anchored sill. This type of construction is not widely used today.

Platform Frame Construction

In platform-frame construction, first floor joists are completely covered with sub-flooring to form a platform upon which exterior walls and interior partitions are erected. This is the type of construction most generally used in home building.

Post and Beam Construction

In post and beam construction, wider beams are spaced up to eight feet apart. Floors and roofs are covered with 2-inch planks. These serve as subflooring and roof sheathing, and, where tongue-and-grooved planking is used, provide an attractive finished floor and ceiling. The ends of the floor and roof beams are supported on posts which provide the wall framing. Supplementary framing between posts permits attachment of wall sheathing and exterior sidings.

Hot Water Boiler

Many people who use hot water boilers for their heat also use a domestic hot water coil in their boiler, which produces hot water for domestic use. The hot water boiler domestic coil is located inside the boiler heat exchanger and uses a constant supply of water which it heats as it passes through the coil. This water supply is separate from the water supply which is in the boiler loop. It is not the same water and has a different pressure than the water which is used for heating the home.

Solar Hot Water Heaters

Solar hot water heaters are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage. The system may use electricity for pumping the fluid, and have a reservoir or tank for heat storage and subsequent use. The systems may be used to heat water for a wide variety of uses, including home, business and industrial uses.

Plumbing

Structural plumbing is actually made up of two systems: the water system that comes into the home for drinking, cooking and washing and the drainage system for wastewater. Building codes specify how each system must be installed.

Tankless Hot Water Heaters

Tankless hot water heaters are basically "on-demand" water heaters. When the consumer opens the hot water faucet, a flow switch senses the flow of water and the water heater fires up and begins heating the water passing through its heat exchanger. Within seconds hot water comes out of the faucet. There is no tank to maintain or worry about leaking in the future. These systems are economical and last many more years than a regular water heater with a tank. They require little maintenance. Since they are on-demand, the tankless water heater only uses fuel when hot water is needed.

R-Value

The R-value or R-factor is the degree or resistance to the heat transfer. The R-value of a surface determines how quickly heat is conducted across it. The larger the R-value, the greater the insulation value. Exterior walls will usually use insulation with an R-value of 13, floors and crawl spaces R-19, attics R-30 or higher.

Electrical

The installation of an electrical system should take into consideration both present day and future needs. The standard service is 120/240 volts of electricity. The electricity is brought into the building through a system of outside cables which can be either above ground or below ground.

Ventilation

Ventilation is the intentional movement of air from outside a building to the inside. Ventilation air is that air used for providing acceptable indoor air quality. When people or animals are present in buildings, ventilation air is necessary to dilute odors and limit the concentration of carbon dioxide and airborne pollutants. Ventilation air is often delivered to spaces by mechanical systems which may also heat, cool, humidify and dehumidify the space. Many heating and cooling systems are referred to as HVAC (Heating, Ventilation, and Air Conditioning) systems. Ventilation systems have exhaust fans and ducts to remove stale air from the building, while introducing fresh air to replace what has been exhausted.

Venting Requirements

Water and wastes are carried from the kitchen, laundry and bathroom fixtures through a system of pipes that lead to the main structure drain. A venting system is made up of pipes that allow air to flow to and from the drainage system. The vent system allows gases and odors to circulate up through the system and escape into the outside air. Every plumbing fixture should be connected to a vent pipe that leads to a roof vent pipe. The local building code dictates the venting requirements.

Footings

When preparing the site for a structure, the ground itself forms the bed for the structure's foundation. That part of the foundation which transmits loads directly to the soil is called the footing. The purpose of the footing is to spread the load over a greater area to prevent or reduce settling. The footing holds the entire weight of the building.