Ch. 19 - Basic Construction

Major Types of Foundations: Basement

A basement is part of a house or building partially or entirely below grade (ground level) that supports the rest of the structure. Basements are at least one full story in height and are formed by excavating the site before a house is built. A house may have a full basement or a partial basement. With a partial basement, only some of the home's footprint is excavated. The remainder is either a slab-on-grade foundation, typically found under a garage, or is partially excavated to create a crawl space with concrete walls. Basement walls, which sit on the concrete footers, can be constructed from many different materials. The most common is poured concrete or concrete block. However, it is not unusual to find brick and stone—and even treated timbers—in older dwellings. The greatest advantage of a basement is the extra space that it offers, but there are disadvantages as well. A basement foundation is the most expensive and time consuming to construct. Also, there is a greater risk of mold problems or foundation damage from flooding.

Foundation: Construction Termite Treatment

After a foundation is set, new residential construction must be protected against the invasion of termites as set forth by North Carolina's building code. Though other methods of termite treatment are allowed in North Carolina, two common methods are: Wood treatments applied to critical structural wood members during construction. Soil-applied liquid treatments applied around the foundation walls and piers.

Roof Components: Outer Roof Coverings

After the sheathing is in place, the roof is ready for its final covering. Different covering options include: Composition Asphalt Shingles. Composition asphalt is the most common type of roofing material. The shingles are composed of a base material of fiberglass felt with an asphalt coating, followed by granules. Most composition asphalt roofs have lifespans between 15 to 40 years. Wood Shingles or Shakes. Wood, typically cedar, is a traditional roofing material, though more expensive than asphalt. Wood shakes are rough and have an irregular, rustic finish; wood shingles are milled and appear more regular. Although durable, wood roofs require regular maintenance to remove moss and mildew. Slate. Slate roofs are made of very thin slices of slate rock. The weight of a slate roof is tremendous—it is estimated at about 8 to 10 pounds per square foot. Slate roofing is very expensive, compared to asphalt, but if maintained, a slate roof can last for decades. Metal. Metal roofs have been around for a long time and are enjoying a renaissance. While they are generally ribbed steel, a metal roof may imitate the look of other building materials, such as tile. Metal roofs last a very long time, come in a variety of colors and do not require sheathing. Clay Tile. Clay is the oldest known roofing material. It has a distinctive red color and is extremely durable, heavy, and costly. Roof tiles can also be made of concrete, which can be mixed in a variety of colors. Clay tile is more likely to be used in warmer climates.

Roof Components: Sheathing and Roofing Materials

After the trusses are in place, sheathing is installed to strengthen the roof and serve as a base for exterior weatherproof covering (often roofing felt). In home construction, builders generally use plywood or oriented strand board (OSB). Flashing is added to protect areas of the roof where two or more types of materials join, for example, a strip of metal over the seam between a brick chimney and a shingle roof, or the point at which two angles of a roof meet. This prevents water from penetrating the joint. There are other parts of the roof that are also more visible: The eave is the lowest section of the roof that projects beyond the side walls. The eave protects the property from the elements. The soffit is the underside of an arch, beam, overhang, or eave. It is often ventilated to provide adequate airflow to the attic. The fascia is a panel or board facing the outer edge of the soffit. If the property has gutters, they are fastened to the fascia. Fascia can act as decorative trim to give the roof a finished look. The frieze board is board under the soffit on top of the exterior wall. Gutters and downspouts reroute water that falls on the roof away from the foundation.

Air Conditioning Systems

Air conditioners remove heat and humidity from a house to cool it. An air conditioner can be used to cool one room in a home or a central forced-air system powered by electricity, gas, or oil used to cool the entire home. In its most basic sense, a central forced-air conditioner system is a closed system through which a chemical refrigerantflows. In its simplest description, a typical air conditioner has three main parts: Evaporator. The evaporator is most often located inside the house, typically mounted in a sealed box called a plenum on the furnace. The evaporator has coils through which a cold liquid refrigerant runs. A blower moves warm air from the house over the coils, which absorb the heat. The now cooled air is blown through the ductwork of the house. Compressor. As the liquid in the coils heats up, it expands and becomes a gas, which flows into the compressor. The compressor, usually located in an outdoor unit, acts like a pump that pressurizes the gaseous refrigerant from the evaporator, turning it into a hot, high-pressure gas. Condenser. The high-pressure gas then moves across the condenser coils, also located in the outdoor unit. This allows the heat to be released into the outdoor air. As heat is released, the coils condense the gaseous refrigerant back into a cool liquid. The liquid flows into the evaporator, and the cycle begins again.

Basic Foundation Components

All home designs are structurally built on some type of foundation, such as a concrete slab, crawl space, or basement. We'll look at these options in a moment. The foundation rests on footers that must provide a firm base that will withstand the forces of nature, which include gravity, frost heaving, and soil swelling. Footers, in conjunction with the foundation, transmit the load of the structure to the soil. Let's look at the different types of foundations.

Foundation: Damp-proofing and Waterproofing

Also to comply with building codes, foundation walls that retain earth and enclose habitable or usable spaces located below grade must be damp-proofedfrom the top of the footing to the finished grade. Exterior basement walls that retain earth and enclose habitable or usable spaces located below grade most often must be waterproofed.

Chapter Overview

As a real estate licensee, it can be very helpful to be familiar with specific terms that define the components of a building. When walking a client through a new building, talking with a contractor, or assessing an existing house, you should be prepared and informed. In this chapter, you will review the basic components that are part of housing construction, such as the foundation, framing, exterior walls, and heating/cooling systems. You will also learn about state and federal laws and entities that regulate the construction business. Chapter Outline and Objectives This chapter is divided into two units and a chapter quiz: Construction Components Construction Regulations and Requirements After completing this chapter, you will be able to: Identify foundation, framing, roofing, and exterior wall components that are foundational to the construction of a house. Recognize construction elements that secure the home, such as windows, doors, insulation, and systems for ventilation, heating, and cooling. Identify key regulations and organizations that govern the construction business, including requirements for a building permit, certificate of occupancy, and contractor licensing.

Key Terms

Blueprint—A detailed diagram, usually created by an architect, that is used to evaluate design, determine feasibility, and guide construction of a structure. Building Codes—Written criteria, typically adopted and enforced at the local level, intended to protect the public by imposing minimum construction standards related to methods and materials, sanitary equipment, electrical wiring, fire prevention, etc. Building Inspection—Formal process through which government authorities, usually local, are charged with ensuring compliance with prevailing building codes. Building Permit—Official government document obtained from the appropriate authority acknowledging the proposed construction meets the department's standards and granting permission for the work to be performed. Certificate of Occupancy—Issued to builders after all inspections have been made and the property is deemed fit for occupancy. International Building Code—A model developed by the International Code Council (ICC) that sets minimum standards, often used as a baseline for stricter codes at the local level.

Codes and Compliance

Building codes protect the public by setting minimum construction standards, including specific methods and materials, sanitary equipment, electrical wiring, fire prevention standards, etc. Building codes usually are specific to the type of work being done and the type of structure being built. Most states have adopted building code statutes based on the provisions of the International Building Code, a model that was developed by the International Code Council (ICC). It is important to note, however, that while states may set minimum building standards, local jurisdictions can pass stricter requirements. Building codes adopted and enforced by local jurisdictions generally allow older work in residential properties to stay in place, as long as the work was up to code at the time it was installed and is presently in safe condition. Often, though, if remodeling or improvements are performed, all conditions must reflect the current code for that jurisdiction. Builders, particularly commercial builders, must comply with the accessibility provisions of the Americans with Disabilities Act (ADA). If stricter standards are later imposed, owners may need to renovate. Fines and injunctions are used to enforce this law.

Certification of Occupancy Requirement

Building inspection is the process through which government authorities, usually local, ensure compliance with prevailing building codes, zoning ordinances, etc. Since building codes are written to address safety issues, enforcement of these codes through inspection is in the community's best interest. Depending on the project and the local requirements, there may be separate inspections, for example, for electrical, plumbing, structural, and mechanical. Building inspectors typically visit a site multiple times throughout the construction process. Once construction is complete, a final inspection must be conducted. If the structure complies with all relevant building codes, the jurisdiction issues a certificate of occupancy, which is a required state permit describing the legal use and occupancy of the building (NCGS § 160A-423). A certificate of occupancy also confirms: The construction matches submitted plans. All applicable zoning laws, ordinances, and regulations have been followed. All required approvals were obtained and the necessary paperwork filed. All required fees have been paid. A certificate of occupancy is required for all work for which a building permit was required and whenever the general occupancy classification for a building is changed. Building inspections are NOT the same as home inspections performed at the request of a prospective buyer. Building inspectors work for local governments to validate compliance with building codes.

British Thermal Unit

Determining the correct size of the furnace or air conditioner a house needs is truly a science. Not only must the size of the house be taken into consideration, but also the number of windows, type of foundation, amount of ventilation, the site (shaded or sunny), and often the biggest unknown—how the house is insulated. The capacity of furnaces and air conditioners is given in British Thermal Unit (BTU) per hour. The BTU is the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. Knowing how many BTUs the house loses per hour is essential. For example, a well-insulated 2000-square-foot house in a moderate climate might need 50 BTUs per square foot, or a 100,000 BTU furnace (2000 square feet x 50 BTUs = 100,000). But you need to also consider the efficiency rating of the furnace, which measures the actual output. Let's say that 100,000 BTU furnace has an efficiency rating of 80%. The actual output is only 80,000 (100,000 x .80 = 80,000). To find a furnace that would deliver the necessary 100,000, divide by the efficiency rating: 100,000 / .80 = 125,000. A 125,000 BTU furnace with an 80% efficiency rating would deliver the desired 100,000 BTU. You may see 100,000 BTUs as 100K, with K being shorthand for one thousand.

Doors

Doors contribute to the overall energy consumption in much the same way as windows. In addition to the potential for air leakage, the type of building material of the door and the frame it is connected to may contribute to the home's thermal heat gain. However, unlike windows, most doors do not have much direct sunlight coming through, so they are not as big a contributor to solar heat gain. Door types can include flush, panel, sliding glass, atrium, and French. Sliding glass doors, atrium doors, and French doors must be considered in the same way as windows in terms of heat, light, and air leakage.

Weather-Stripping and Ventilation

Doors, windows, and other potential areas where elements like rain or air may enter must be sealed. The sealing of openings around doors and windows to protect against elements entering the home is called weather-stripping. For maximum energy efficiency and moisture control, houses should be relatively airtight. However, they also need to have good ventilation. Interior air can contain high levels of pollutants and irritants—including dust, pet dander, and chemicals—as well as high moisture levels. The long-term effects of moisture, mold, and mildew are detrimental to the building, and can, in extreme cases, cause materials to rot. A certain level of natural ventilation is achieved by airflow through windows, vents, and gaps in the building envelope. Even if a house is drafty, however, it may not have a reliable source of fresh air, as natural ventilation depends on factors such as temperature and wind. Effective ventilation involves both a controlled ventilation rate and a means of distributing the fresh air to habitable spaces. Ventilation systems are often comprised of an exhaust fan and ducts to remove stale and polluted air from the home. To ensure proper ventilation, the building should have a minimum ventilation rate of 15 cubic feet per minute (CFM) per person. This rate should be continuous when the property is occupied. Attic ventilation systems and vapor barriers prevent warm moist air from accumulating in the attic, which may damage the structure.

Key Terms

Foamed-In Insulation—An insulation product that is sprayed into irregularly shaped spaces as a liquid and expands into a plastic solid. Footer—The support for the foundation of a building. Footers are installed below the frost line and are wider than the foundations that they support. Foundation—The support for a building that can be constructed of stone, poured concrete, pre-engineered concrete walls, concrete block, or even wood. Framing—The basic load-bearing skeleton of a structure to which the interior walls, exterior walls, and roof system are attached. Loose-Fill Insulation—An insulation product made of fiber pellets or loose fibers that can be blown into small, tight-fitting areas. Pitch—A roof's vertical rise in inches, divided by its horizontal span in feet, indicating its slope. R-Value—A measurement of thermal (heat) resistance. A higher R-value of insulation indicates greater resistance to heat flow. Sheathing—A layer of boards or other wood or fiber materials applied to the outer studs, joists, and rafters to strengthen the structure and serve as a base for exterior weatherproof covering. Siding—The outer covering for a building's exterior walls, designed to shed water and protect the building from the elements.

Unit Summary

Foundation types include concrete slabs, crawl spaces, or basements. Framing types include platform, post and beam, and balloon. Roof framing styles include gable, hip, gambrel, mansard, and flat. Sheathing is installed to strengthen the roof and serve as a base for exterior weatherproof covering. Exterior finishes include sheathing, house wrap, and siding to protect the walls of the house from the outside elements. The primary way to combat air leakage and the resulting energy consumption is by placing insulation around the building envelope as a thermal boundary. Insulation is rated by its R-value, which is a measure of the insulating value or resistance to heat flow through a material or an object. Two critical elements of the envelope responsible for the transmission of heat and air leakage are windows and doors. The heating system of a house is comprised of several elements, including such things as a furnace or heat pump, flue, ducts and ductwork, registers, and thermostat. Common types of heating systems include: Hot water system, steam system and forced warm air system. Air conditioners remove heat and humidity from a house to cool it. In its most basic sense, an air conditioner is a closed system through which a chemical refrigerant In its simplest description, a typical air conditioner has three main parts: Evaporator, compressor, and condenser.

North Carolina Uniform Residential Building Code

In North Carolina, state building code requirements are located in the North Carolina Uniform Residential Building Code. In 1933, the North Carolina Building Code Council was established in cooperation with the Office of Insurance to write the initial North Carolina Building Code. It was first adopted in 1935 and passed by the North Carolina Assembly in 1941. In 1957 the state legislature rewrote the 1933 law and expanded the responsibility of the North Carolina Building Code Council. The purpose of the North Carolina Uniform Residential Building Code is to protect the public from any dangerous or unsanitary conditions in design and construction.

Major Types of Foundations: Crawl Space

In some parts of the country, builders choose to employ a crawl space foundation (also known as pier and beam foundation). Instead of digging a trench as a footer, the builder drills holes, and either pours concrete into the holes to create columns or uses pre-made concrete blocks or timbers. The piers, which should be wider at the bottom than at the top, transfer the load of the structure into the ground. Concrete or timber beams then span from pier to pier to support the exterior walls of the house. With this type of foundation, the floor of the house is elevated above ground level, creating a crawl space between the ground and the floor of the structure. The crawl space is typically accessible from an exterior scuttle so that utilities such as electrical wiring and plumbing can be serviced. The crawl space is generally about 18 or 24 inches high, but might also be partially excavated and, therefore, as much as 3 or 4 feet high. A crawl space foundation is more stable in areas where the soil is subject to contraction and expansion or in areas that receive a lot of rain or are flood-prone. A disadvantage to this type of foundation is the crawl space can be enticing to pests and may be prone to moisture problems. To rid the home of potential moisture issues, foundational vents are installed through the exterior foundation walls. Construction ventilation systems are covered more later in this chapter.

Insulation R-Value

Insulation is rated by its R-value, which is a measure of the insulating value or resistance to heat flow through a material or an object. The more effective the insulation, the higher the R-value it will have. Higher R-value insulation is generally denser and thicker. The North Carolina Uniform Residential Building Code requires insulation with: R-value 13 in walls. R-value 30 in ceilings. R-value 19 in floors. Higher R-values are required in the colder, mountainous counties of northwestern North Carolina.

Insulation

Insulation is the primary way to combat air leakage and create a sound barrier. Ensuring a proper amount and type of insulation is one of the most cost-effective decisions made during new home construction. Floor, walls, ceiling, and attics are all parts of a structure that need to be insulated against outside elements. Common types of insulation materials include: Fiber Blanket. This insulation often comes in a pre-measured width for use with standard stud, joist, or rafter spacing. It is made of a mineral fiber, such as fiberglass, mineral wool, plastic, or natural fibers, generally enclosed in a paper covering. Blanket insulation can be applied to unfinished walls, floors, and ceilings as well as fitted between studs, joists, and beams. Loose-Fill or Blown-In. This type of insulation is blown into an area, often the attic space, or other building cavities that may be irregularly shaped or have obstructions. It is made of fiber pellets or loose fibers and is good for filling small, tight areas. The materials used are cellulose, fiberglass, and mineral wool. Foamed-In. Foamed-in insulation is sprayed into an area as a liquid then expands into a plastic solid. It is often made of a polyurethane mixture and works well for insulating irregularly shaped spaces. Foam beads or liquid foam can also be applied to unfinished walls. Like blown-in insulation, foam is a good solution if the insulation needs to go into an irregular space or around a barrier.

Construction Components

Introduction This unit covers the fundamental components of a house's structure and the systems that stabilize the ventilation, heating, and cooling of the home. After completing this unit, you will be able to: Identify different types and components of foundations used in the construction of a residential house. Identify different framing systems and components for floors, walls, and ceilings/roofs. Recall materials required for the construction of exterior walls. Identify types of insulation materials and R-Value requirements set forth by the North Carolina Uniform Residential Building Code. Recognize types and components of windows and doors and how they both impact home energy. Recall different ventilation, heating, and cooling systems.

Construction Regulations and Requirements

Introduction This unit describes what must be done before actual construction can begin and outlines state and federal regulations that need to be observed throughout the construction process, such as obtaining the proper permits and passing the required inspections. After completing this unit, you will be able to: Identify steps to the pre-construction process, including developing a blueprint and obtaining a building permit. List federal and state building codes and entities that protect North Carolina consumers. Recall North Carolina-specific requirements specific to a building permit, certificate of occupancy, and contractor licensing.

Basic Types of Home Designs

Let's quickly review some common house designs, defined by their functional layout and the number of stories or levels that a house has: One Story. One story residences have one level of living area. The roof structure generally has a medium slope. The attic space is limited and is not intended as a living area. One-and-One-Half Story. One-and-one-half story residences have two levels of living area. Characterized by a steep roof slope and, often, dormers, the area of the upper level, whether finished or unfinished, usually equals 40% to 60% of the lower level. Multi-Story. Two story residences have two levels of finished living area. The area of each floor is approximately the same. The roof structure has a medium slope. The attic space is limited and not designed for usable living area. Two-and-one-half-story residences have three levels of living area. Having a steep roof slope with dormers, the third floor, whether finished or unfinished, usually equals 40% to 60% of the second floor. Split-level residences have three levels of finished living area: Lower level, intermediate level, and upper level. The lower level is immediately below the upper level, as in a two story. The intermediate level, adjacent to the other levels, is built on a grade approximately four feet higher than that of the lower level.

Framing Systems

Next, the builder installs the vertical framing elements that delineate the house. The framing is the basic load-bearing skeleton to which the interior walls, exterior walls, and roof system are attached. Generally, all perimeter walls are load-bearing, although most houses have some interior load-bearing walls as well. There are three basic frame construction types: Platform framing - This is a common type of framing by which the house or building is constructed one story at a time, with each story serving as a platform for the next. With this method, the builder uses studs as the vertical framing members. The studs are cut to the height of each story, capped with horizontal top plates that create a platform to which the studs for the next story are attached. The top plates support the floor joists for each story as well as the ceiling joists. Balloon framing - With this type of framing, long studs are used to frame the entire height of the house, from the foundation to the roof. Horizontal elements (called ledger boards) are nailed inside these tall studs to provide support for the floor. Balloon framing is no longer permitted as a construction method by most building codes because of its poor fire-resistant design. Post and beam framing - With this framing, the floors for second stories and above are supported by beams that sit on posts and the outside wall perimeter. The roof sits on beams, too. With post supports, as opposed to studs, fewer interior walls are needed, allowing for larger, more open space. Posts, beams, and frame members are heavier than other types of framing elements and, in the case of wood, may often be left exposed for decorative purposes.

Unit Summary

Once the site is selected, planning and pre-construction begin with the specifications, or A blueprint is usually developed concurrently and is used to evaluate design, determine feasibility, estimate costs, and, ultimately, guide the construction of a structure. The next step in the construction process is to submit the building specifications and blueprints to local authorities. The local building department reviews these documents to ensure they meet the appropriate codes and standards. Then, they issue the permits that grant permission for the project to proceed. Building inspection is the process through which government authorities, usually local, ensure compliance with prevailing building codes, zoning ordinances, etc. Once construction is complete, a final inspection is conducted. If the structure complies with all relevant building codes, the jurisdiction issues a certificate of occupancy. Most states have adopted building code statutes based on the provisions of the International Building Code, a model that was developed by the International Code Council (ICC). In North Carolina, state building code requirements are located in the North Carolina Uniform Residential Building Code.

Specifications and Blueprints

Once the site is selected, planning and pre-construction begin with the specifications, or specs. These are detailed written documents, usually created by a builder or architect, that describe the requirements and scope of the work, including materials, standards, and expected quality of the finished product. The specs also prescribe the construction methods and the project responsibilities. A blueprint is usually developed concurrently. Blueprints are detailed diagrams, drawn to scale, that show the size and position of rooms, walls, doors, stairs, windows, systems, major fixtures, etc. Blueprints are used to evaluate design, determine feasibility, estimate costs, and, ultimately, guide the construction of a structure. While blueprints guide construction, the specs describe the quality, type, and quantity of finish materials, such as flooring, cabinetry, etc., that are needed for an accurate bid and successful completion of the project. For example, the drawing may indicate that a kitchen floor is tile, but the materials list in the specs would indicate the exact manufacturer, size, color, etc., of the tile to be used. Generally, the specs are the final authority in construction projects, but because the blueprint and specs have potential for deviation, construction contracts may contain an order of precedence clause that indicates which—the specs or the drawings—governs in the event of any conflict.

State Building Permit Requirement

Per the requirements of state law (NCGS § 160A-417), a person will need to file for a permit to complete a construction project. The permit application is filed with either the county or city where the property is located.

Exterior Walls: Sheathing, House Wrap, and Siding

Recall, sheathing is required to protect the walls of the house from the outside elements. The most common materials are, again, plywood or OSB. After placing a layer of wood over the frame, builders cover it with some type of house wrap, which is usually a treated paper or plastic film designed to keep air and water out while allowing water vapor to escape. A common example is Tyvek®. In the past, tar paper (asphalt treated paper or felt) was used to insulate the home, but plastic house wrap has replaced the use of tar paper. Siding is the outer covering for a building's exterior walls, designed to shed water and protect the building from the elements. Materials are chosen for their ability to stand up to the elements, to protect the house, and to keep it looking good with minimal maintenance. Aluminum siding is common on older homes. In addition to being relatively inexpensive, aluminum is easy to maintain. The main drawback to aluminum is that it can dent easily and needs to be painted after the factory finish wears off (about 10-15 years). Vinyl siding is a more common siding today. It is relatively inexpensive and easy to maintain. Today's vinyl can imitate more expensive wood siding or shingles. Vinyl siding can typically last 25 years or so. Wood siding (also called lap siding or clapboard) is common on older homes because it is tough, economical, and it enhances the appearance of a home. It is more expensive than vinyl or aluminum, and will last longer, but needs regular maintenance and painting. Wood shakes and wood shingles, usually cedar or redwood, are popular choices for homes but are more expensive than wood siding. With some maintenance, wood shakes and shingles can last 50 years or more. Stucco is a popular material used to cover houses. Stucco is durable because it has no seams to let water or moisture in, but it can crack from repeated freeze-thaw cycles. Brick and stone veneer sidings are the most expensive types of siding and, arguably, the most attractive and the most durable. Brick and stone are easy to maintain—even cleaning is rarely necessary—although older brick and stone exteriors may show signs of deterioration from the weather and water. Other siding materials include manufactured wood, fiber cement, and synthetic stucco (exterior insulation and finish systems or EIFS).

Framing Roof and Ceiling: Basic Components

Roof framing is a critical part of a structure. A roof rafter is a sloped support beam that follows the pitch of the roof and serves to hold the outer roof covering. Rafters are typically fastened to the roof ridge beam, a horizontal beam at the top of the roof. Roof joists are long beams of wood or steel that support the loadbearing walls of a roof. Trusses are the framework of rafters, posts, and beams that form the support for a roof. For stability, time, and accuracy, builders often install prefabricated roof systems that are placed on the attic floor joists and form the roof support. They have a "W" shape within the structure and are known as truss roofs. With a sloped joist roof, instead of rafters, joists go from the outer load-bearing walls to the pitch of the roof. Since there are no joists parallel to the floor, this construction allows for vaulted ceilings.

Major Types of Foundations: Concrete Slab

Slab-on-grade construction is the cheapest and simplest type of foundation to build. With this method, concrete is poured onto the ground, usually onto a shallow bed of gravel, inside the footers that mark the perimeter of the house. The concrete is usually reinforced with steel mesh or rebar. There is no basement or crawl space; the water and sewer pipes—and sometimes ductwork for heating and cooling—are instead put in place before the concrete is poured. The floor is then laid on top of the concrete foundation. This type of foundation is common in many parts of the country, particularly in warmer climates where there is less risk of shifts due to freeze and thaw. The concrete slab is not appropriate for some soil types, such as heavy clay, and is considered inferior in many markets. In addition to the lower cost, there are other advantages to slab-on-grade foundations. For example, the entrances to the house are typically at ground level, eliminating steps for those with mobility issues. Also, there is no chance of pests getting under the house, and there is less risk for mold.

HUD Minimum Property Standards

The Minimum Property Standards (MPS) supplement model building codes by establishing certain minimum standards for buildings constructed under HUD housing programs. This includes new single-family homes, multi-family housing, and healthcare-type facilities. Until the mid-1980s, HUD maintained separate Minimum Property Standards for different types of structures. Since that time, HUD has accepted the model building codes, including over 250 referenced standards and local building codes in lieu of separate and prescriptive HUD standards. However, there is one major area of difference between the MPS and other model building codes: durability requirements. Homes and projects financed by FHA-insured mortgages are the collateral for these loans and their lack of durability can increase FHA's financial risk in the event of default. More specifically, the model codes do not contain any minimum requirements for the durability of such items as doors, windows, gutters and downspouts, painting and wall coverings, kitchen cabinets and carpeting. The MPS includes minimum standards for these items to ensure that the value of an FHA-insured home is not reduced by the deterioration of these components. HUD requires that each property insured with an FHA mortgage meets one of the nationally recognized building codes or a state or local building code based on a nationally recognized building code. In areas where such state or local codes are used, HUD determines if the state or local code is comparable to the model building code.

Building Permits

The next step in the construction process is to submit the building specifications and blueprints to local authorities. The builder may also need to submit a plot plan showing the proposed layout of the property site, including the building's position and the elevation of the land. Plot plans provide necessary data related to excavation and grading. Submission of these documents is the first step in obtaining necessary building permits. The local building department reviews these documents to ensure they meet the appropriate codes and standards. Then, they issue the permits that grant permission for the project to proceed. The issuance of permits also prompts the government authority to monitor the project and follow up with appropriate inspections. In some jurisdictions, one building permit may cover the entire new construction, building addition, or renovation project. In other jurisdictions, separate permits may be needed for various elements of the construction, e.g., the framing, the electric, plumbing, etc. In those cases, different inspectors may be engaged.

Heating Systems - Central Forced Warm Air

The power sources from heating can come from many different sources, such as the sun, gas, oil, electricity, coal, and wood. Most homes today are heated using forced-air furnaces. The components of this system include a furnace, a blower, a heat source, distribution air ducts, and return air ducts. In this system, air is heated in the furnace then a blower moves the air through ductwork in the walls. Eventually, the warm air enters a room through a register in the floor or wall. Cool air is then recirculated through return air ducts. Common sources of heat for forced-air furnaces include: Gas or Oil. The fuel is burned in a chamber of the furnace to heat the air. Fueled furnaces must have a flue to vent combustible gases to the outside. Electricity. An electric furnace uses heating elements, usually metal or ceramic, to heat the air. As electrical current passes through a heating element, it encounters resistance, which creates heat.

Framing Floor and Walls: Structural Support Elements

The sill plate is the bottom piece of a frame that is anchored horizontally to the foundation. The sill plate provides a nailing surface for the floor or wall system and is the first layer of wood that starts construction of the house. Floor joists are long horizontal beams of wood or steel that span the foundation and support the floor. Wood or metal bridging may be installed between the joists to prevent them from twisting. The floor joists sit on the sill of the foundation walls around the perimeter of the building, supported by and perpendicular to the girder. The girder is the main support beam that runs from one foundation wall to another. Girders may be steel I-beams or timber. The subfloor, often plywood, is attached to top of the joists and girders. Walls are framed out with vertical studs, often 2x4 lumber, attached to horizontal sole plates and top plates and supported by horizontal blocking. Wood reinforcements installed above openings for door and window placement are called headers.

Heating Systems - Other Types/Methods

There are other heating systems available, for example: Hot Water and Steam Systems. These systems use a boiler, which is an enclosed vessel in which water is heated. Hot water or steam is then circulated through pipes into radiators or other devices in walls or floors that radiate heat to warm the room. Steam eventually becomes water again, which is recirculated back to the boiler to be heated again. Boilers can be fueled by wood, coal, oil, natural gas, propane, or electricity. Electric Heat Pumps. Heat pumps can be used in addition to or instead of a furnace and air conditioner. To warm a house, a heat pump moves heat from the outdoors into the house. To cool the house, it moves heat from the house to the outdoors. Because the pump transfers heat, as opposed to generating heat, the heat pump is more energy-efficient than furnaces and air conditioners. However, it is generally not effective in cooler climates. Gravity Warm Air Heating. More often found in older homes, a gravity heating system allows warm air to rise naturally throughout a home using a furnace without a duct distribution system or fan. Electric Baseboard. Baseboards that generate heat can be installed in every room without ductwork. Baseboard heat is often used as a supplement to other heating systems. Space Heating Systems. Wood stoves and fireplaces are space-saving heating systems that can be included in a home. Whether fueled by wooden logs or pellets, a wood-burning stove can be an effective way to supplement more traditional heating systems. Other types of space heaters include gas heaters, kerosene heaters, and electric heaters. Alternative, environmentally friendly systems for heating homes include solar and geothermal energy. Solar. Solar panels, usually on the roof, can harness the thermal energy from the sun to heat homes. Geothermal. Below the earth's surface, temperatures remain relatively constant. A geothermal heating system transfers heat from the earth to provide warmth without the use of fossil fuels.

Contractor Licensing

To ensure compliance with state and federal building code requirements, general contractors in North Carolina must be licensed by the North Carolina Licensing Board of General Contractors. The Licensing Board for General Contractors separates their general contractor licenses into three different limitations based on financial information and the project size: Limited license for individual projects not exceeding $500,000. Intermediate license for individual projects not to exceed $1 million. Unlimited license for any size project. See the North Carolina Licensing Board of General Contractors website for more information on contractor licensing.

Windows

Two critical elements responsible for the transmission of heat and air leakage are windows and doors. While windows allow for natural light, views, and the health of the occupants, each pane of glass can be a source of air leakage if the sealis not in good condition. However, air leakage around the window is not as critical as the solar heat gain. Window glass transmits between 20% and 80% of the sun's heat into a home, making it a major thermal flaw. One way to combat this is the use of low-emissivity window glass. Low-emissivity, or Low-E, glass has a clear, microscopic coating that allows short-wavelength sunlight to pass through, but reflects the long-wavelength infrared radiation that emits heat. Low-E windows can be used in most climates, but it is important to make certain the coating is on the correct surface of a double-pane window to achieve the energy goal: In cooler climates, the coating should be on the interior surface of the exterior pane. In warmer climates, the coating should be on the exterior surface of the interior pane. Window types can include sliding windows (double-hung and horizontal sliding), swinging windows (casement, jalousie, hopper, and awning), and fixed windows (picture, bay, and bow). Window components include the header and the sill at the top and bottom of the window. The window jamb frames the inside of the window for structural support. The window sash is the part of the frame that holds the window glass in place. Decorative grill-like patterns on windowpanes can be made with the use of muntins (horizontal dividers) and mullions (vertical dividers).

Framing Roof and Ceiling: Major Designs

You can tell a lot about the style of a roof from its pitch or the degree of a roof's slope. More specifically, the pitch is a roof's vertical rise in inches, divided by its horizontal span in feet. However, most people envision a specific roof stylewhen they think of pitch, not a mathematical equation. A few common roof styles include: Gable. This triangle-shaped roof is one of the most common styles. A gable roof has two equal sides that meet at the ridge. Hip. This roof has a slope on all four sides, forming a ridge at the roofline. There are many variations of a hip roof, depending on the pitch. Gambrel. This is typically a two-sided roof with an upper slope that's shallow and a lower slope that is steeper. Like gables, the slope of the roof may appear on the front or side of the home. Mansard. This is a combination of a hip and a gambrel roof. The upper slope is essentially a hip roof, and four lower slopes are steep. Mansard roofs often have dormers. Flat. Flat roofs are most often used for contemporary homes, though they also may be found on porches and garages.