Site Valuation Methods and Appraisal Math

4. describe the factors that influence proper siting of a house on its lot,
5. describe the three basic activity zones of a house and describe their relationships to each other;
6. describe the characteristics that affect functional utility in the various rooms of a
   house,
7. identify the characteristics of various building components that can affect value, and
8. understand the technical terminology used to describe residential construction.

I. Classification of Houses
Houses are generally classified on the basis of four characteristics: the number of units, whether the building is attached or detached, the number of stories and the architectural style.
The NUMBER OF UNITS refers to the number of separate households that the building is designed to accommodate. Although usage may vary in different areas, the term “house” is most often used to refer to a SINGLE-FAMILY RESIDENCE. If a building has multiple units that share a common access and other common areas, it is usually referred to as an APARTMENT BUILDING.
A DETACHED HOUSE is one that is not connected to any other property. ATTACHED HOUSES share one or more walls, called “party walls,” that are jointly owned by the two adjoining properties. ROW HOUSES, common in many urban areas, are an example of attached dwellings. Ownership of an attached dwelling often involves a PARTY WALL AGREEMENT, which assigns responsibility for maintenance and repair of the party wall(s) (see Figure 7-1).
A. TYPES OF HOUSES
The “type of house” refers to the number of stories or levels in the house, and their relationship to each other.
Although modern construction methods allow for all sorts of variations, the vast majority of houses fall into five basic “type” categories (see Figure 7-2):
9. one-story,
10. one and one-half story,
11. two-story,
12. split-level, and
13. bi-level (also known as split-entry or raised ranch).

1. One-Story House
   A ONE-STORY HOUSE, often called a “ranch” or “rambler,” has its entire living area on the ground floor. It may or may not have a BASEMENT, which is a room of full story height located below the first floor, at least partially below ground level, and primarily not used for living accommodations.
   The advantages of one-story houses include: ease of exterior maintenance, flexibility of floor plan design and the fact that there are no stairs to climb.
   On the down side, this type of house is relatively expensive to build; by comparison, a two-story house with the same exterior dimensions has twice the living area, with essentially no extra cost❓ for roof or foundation. (Roof costs for a one-story house are often minimized by using a low pitched roofline.)
   One-story houses also require a greater amount of lot space in relation to the amount of living area, so they may be inappropriate❓ or impractical on small or narrow lots.
2. One and One-Half Story House
   Also known as a Cape Cod, the ONE AND ONE-HALF STORY HOUSE has a steeply pitched roof that permits part of the attic area to be used for living space. Roof dormers, which add to the amount of usable upstairs space, are a common feature of this type of house. As in the case of one-story houses, the foundation may or may not include a basement. Construction costs per square foot tend to be lower for one and one-half story houses than for one-story houses.
   One and one-half story houses are often built with expandability in mind. Because the ground floor normally has at least one bedroom (and sometimes two), the upstairs level can be left unfinished until the extra space is needed. However, ease of expandability will depend on the quality of the original design and construction, which should allow for adequate access (stairs), ventilation (windows) and plumbing (bathrooms) on the attic level.
3. Two-Story House
   Compared to a one-story or one and one-half story house, the two-story house is more economical in terms of construction cost per square foot of living space.
   The reason for the economy is that square footage can be doubled without doubling foundation and roof system costs. This design also allows for the most living space on a given size of lot. Bedrooms are normally located on the upper floor, providing a natural separation between the public and private areas of the house.
   A concern with all multi-level houses is the design and efficiency of heating and cooling systems. Because heat rises, a poorly designed system will make it difficult to keep the lower level warm in winter, and the upstairs cool in the summer.
   With a well designed system, however, heating and cooling efficiency may actually be greater than for single-story houses, since the building has less exterior surface area relative to the amount of heated or cooled interior space.
4. Split-Level House
   A SPLIT-LEVEL HOUSE has three or four different levels, which are staggered so that each level is separated from the next by half of a flight of stairs. Bedrooms and baths are located
   on the top level. Half a flight down are the main entry, living room, dining room and kitchen. Down another half-story, beneath the bedroom level, is space for a family room, den or spare bedroom; the garage is often located on this level as well. A fourth level, equivalent to a basement, may be located below the living/dining/kitchen space.
   The design of a split-level home lends itself to a sloped lot, where the garage and main entry can both open out at grade level. On a flat site, the main entry will be raised one- half story above the finished grade.
   A split-level house has some of the same benefits as a two-story house in terms of construction, cost efficiency and natural separation of the various functional areas of the home.
5. Bi-Level House
   A BI-LEVEL or SPLIT-ENTRY HOUSE has two main levels, one atop the other, with an entry or foyer located on a level halfway between. The lower level is sunk about halfway below ground, so the entry is even with the grade level. This design is sometimes called a “raised ranch,” since it is essentially a one-story home with a finished basement that has been raised partially out of the ground. The main rooms of the house are all on the upper level, with the lower story used for a family room or rec room, and perhaps a spare bedroom.
   Since the lower level of a split-entry house is partly below ground, special care must be taken to provide adequate insulation and moisture proofing. Another drawback to this design is the lack of a basement or crawlspace in which to run pipes and ductwork.
   Nevertheless, split-entry homes are cost-effective to build, and the finished lower level space is considered part of the “gross living area” for appraisal purposes in many parts of the country.

II. Architectural Styles
ARCHITECTURAL STYLE is the character of a building’s form and ornamentation.
If homebuyers in a particular area do not find a particular architectural style desirable, homes of that style are likely to sell for less than similar❓ size homes having architectural styles which are more desirable within that community.
Architectural styles have traditionally been influenced by local factors such as climate and the availability of different building materials.
There are many examples of traditional architectural styles that are adapted to a particular location: Spanish style houses with thick adobe walls and tile roofs in the southwest desert, Southern Colonial houses with deep shaded porches in the hot, humid South, or Cape Cod style homes designed for protection from cold northern winds in New England (see Figure 7-3).
Local traditional styles can still be found in many areas, but location is much less of an influence on architectural style than it used to be.
Builders are no longer limited to using local materials, since modern transportation systems make different building materials widely available at reasonable costs. The invention of central heating and cooling, as well as improved insulating materials, has broadened the range of architectural styles that can be adapted to local climates.
A. COMPATIBILITY
COMPATIBILITY means that a building is in harmony with its use or uses and its environment. In terms of value, one type or style of house is not inherently better or worse than any other. What is most important to value is the compatibility of the design. Compatibility has several different aspects. To maximize value, the design of a house should be compatible with the designs of other homes in the area, with the physical and environmental characteristics of the building site, with the materials used in the construction, and with the preferences of the local market.
First of all, the design of a house should be compatible with the styles of other houses in the local neighborhood.
The market may welcome a limited degree of uniqueness in design, but value will generally suffer if the design contrasts too radically with surrounding houses.
Subdivision developers often impose design restrictions on their developments, because they know that compatibility of design will have a positive impact on property values in the subdivision.
Case/Example: A contemporary style house located in a neighborhood of other contemporary style houses is likely to be viewed positively by the market. But the same house located in a neighborhood of traditional style homes might seem “out-of-place,” and its value could suffer as a result.
Compatibility of design also refers to the suitability of the design for the particular building lot and location. Value is enhanced by a design that takes advantage of physical site characteristics, such as views. The design should also be appropriate for the topography of the site. For example, split-level designs often work well on hilly sites, while colonial style houses do not. Finally, the design should be appropriate for the local climate. A design that is specifically adapted to a hot desert climate, for example, would be inappropriate in an area with cool, rainy weather.
A building’s architectural style is often defined at least in part by the materials used in its construction. Spanish style homes have clay tile roofs, Tudor’s utilize timber framing, contemporary designs incorporate large areas of glass. A compatible design is one where the materials are appropriate to the style.
Case/Example: A clay tile roof on a Cape Cod house would look ridiculous to most potential homebuyers.
The final aspect of design compatibility is perhaps the most important: the design must be compatible with the demands of the market.
The popularity of any given design is influenced by the economic and social forces that affect value. As lifestyles and demographics change, so does the demand for different design features in housing.
Ultimately, it is the local market that determines what is a “good” design, and what is a
“bad” one.
Case/Example: A development of new contemporary style houses is built in an older community with mostly traditional style housing. If the market places an emphasis on the historic character of the community, the contemporary homes will be viewed as incompatible, and their value will suffer. On the other hand, if market forces are creating a demand for more modern housing in the community, the contemporary homes may not be incompatible at all, but may simply represent a new trend in community standards.

III. Elements of House Design
An appraiser must be able to identify the various elements of house design and evaluate❓ any defects in those elements. The elements of house design include siting, interior functional zones, and room characteristics.
He or she may use mobile apps to reproduce accurate renderings to use for comparison purposes.
A. SITING
SITING refers to the placement of the house on the building lot. Placement is normally limited to some extent by building code set-back requirements, which call for minimum distances between the house and the property’s boundaries. Topographic considerations such as slopes or poor soil conditions may also limit where the house may be placed on the lot. Within these limits, however, careful placement of the house on the lot can have a significant impact on value.
There are four basic considerations in designing the placement of a house on its lot: orientation to the sun, orientation to prevailing storm winds, orientation to views, and the division of the lot into functional zones (see Figure 7-4).
Appraisers can create figures like the one above by using appropriate mobile apps.
Orientation to the sun affects the amount of light and heat that can enter the house. In most areas, a design where the living areas of the house face south is considered optimum. This orientation takes best advantage of natural lighting in the most used areas of the home, and helps maximize solar heat gain in the winter. Excessive summer heat gain can be avoided by using wide roof overhangs, which shade the house in summer when the sun is high in the sky, but allow light and heat to penetrate in the winter when the sun’s path is lower.
Screening with deciduous trees is another effective way to block the summer sun but still allow it to shine through in the winter when the trees are bare.
In some areas, orientation to prevailing storm winds is an important siting consideration. In areas that are subject to frequent or heavy storms from a particular direction, it is best to minimize the amount of window area that is directly exposed to the winds, in order to cut down on heat loss. Entries should also be sheltered from the direct path of the storms.
An attractive view can add significantly to the value of a house. Views should be visible from the most used areas of the house. Even if the site does not have an attractive territorial view, careful landscaping can provide a pleasant view of the lot from the living area.
The last aspect of house siting is the division of the lot into functional areas or zones, the so-called public, private, and service zones. The area that can be viewed from the street frontage is the public zone. Areas shielded from the street by the house, or by fencing or other landscaping, constitute the private area. The service area includes access ways (driveway, walkways, etc.) and outdoor storage areas. Good design maximizes the amount of private area available for household activities.
B. INTERIOR FUNCTIONAL ZONE
An appraiser cannot underestimate the importance of FUNCTIONAL UTILITY, which concerns a building’s ability to perform the function for which it is intended according to current
market tastes and standards; as well as the efficiency of use in terms of architectural style, design and layout, traffic patterns, and the size and type of rooms.
A well-designed house should provide space for three basic activities: living, working, and sleeping.
Ideally, the spaces provided for each of these activities should be separated, so that one activity does not interfere with another. For example, bedrooms should be located where they will not be disturbed by activities in the living and working areas of the house.
Figure 7-5 shows how the spaces for the three different activities can be separated into zones. The LIVING ZONE includes the public areas of the house: the living room, dining room, family room and guest bath. The WORKING ZONE is comprised of the kitchen and laundry/ utility room. Bedrooms and private baths are located in the SLEEPING ZONE.
The separate activity areas of the home are connected by hallways, stairs and entry ways, which are sometimes referred to as a fourth zone of the house, the CIRCULATION ZONE. While the three activity zones should be designed to provide separation of the activities, they should also allow for easy circulation between and within zones.
Design features that affect desirability affect value because value is determined by supply and demand features of the marketplace.
A house’s value is affected by the building’s FLOOR PLAN, which is an architectural drawing indicating the exact layout of rooms and illustrating the functional or nonfunctional relationship between them. Structures with wasted space might lack space where it is otherwise desired so that the property will be less desirable to buyers than similar size homes.
How the designer allocates space affects desirability for many buyers. An example is while a custom 3,000 square foot home might have only two bedrooms because that is what the original owner wanted, to most potential buyers, the design would be a negative feature.
Case/Example: In a retirement oriented community, a two-story home without a bedroom on the first level is likely to be far less desirable than one with this feature.
C. ROOM CHARACTERISTICS
1. Kitchens
The kitchen is commonly the most used room of the house, so its design and location have a large impact on the functionality of the overall❓ floor plan.
Kitchens should be conveniently accessible from both the main entrance and service entrance of the house, and should be located adjacent to the dining room and family room, if these rooms are included in the design. Also, the kitchen should be designed so that it is not necessary to walk through the working area in order to reach other rooms of the house.
A critical aspect of kitchen design is the work triangle, which is formed by the sink, refrigerator, and range. The distances between the three points of the work triangle can make the difference between an efficient kitchen design and a poor one. If the distances are too small, the kitchen will be cramped; if they are too great, preparing a meal will seem like a five-mile hike. A distance of four to seven feet between each point of the work triangle is considered optimal (see Figure 7-6).
Kitchen sizes vary considerably. Eighty square feet of space (8’ x 10’) is considered a minimum, but kitchens twice that size are not uncommon. Larger kitchens often include an eating area or family activity area. The design should include adequate counter and cabinet space, and plenty of electrical outlets for kitchen appliances.
Lighting and ventilation are important considerations in kitchen design. Overhead lights should illuminate all areas of the kitchen, and a vent or fan should be located over the cooking area to allow cooking fumes to escape. Natural lighting is desirable, but the placement of windows can be a problem. The best location for a kitchen window is over the sink. Additional windows are desirable so long as they do not take up space needed for wall cabinets.
Windows should never be placed over the cooking area.
2. Laundry/Utility Rooms
Laundry areas are best located where they are convenient to the sleeping area of the house, off the bedroom hallway for example. However, location of the laundry area is not as critical as most other rooms of the house, and laundries are often located in the garage or basement.
The laundry area should be well-ventilated, and located where noise from the appliances will not disturb others.
3. Living Rooms
The living room is the main public room of the house.
It should be located near the main (guest) entry, be separated from the sleeping area, and preferably be on the south side of the house. If the house has a dining room, it should be next to the living room. It should not be necessary to cross through the living room in order to reach the kitchen or bedrooms.
The size and shape of the living room should allow for easy arrangement of furniture. About 200 square feet is the minimum size, and rectangular shaped rooms tend to work best for furniture placement. The modern trend is for smaller living rooms, particularly in homes with a separate family/recreation room.
4. Family Rooms
In many areas, the FAMILY ROOM (also called a recreation room) has taken over the role of the living room as the main center of entertainment and socializing in the house. As part of the living zone, the family room should be separated from the sleeping zone; however, it is usually considered an advantage if the family room is next to (or near) the kitchen.
Since the family room is a center of activity for household members, direct access to the outside is also an asset.
5. Dining Rooms
Dining rooms may be formal or informal. A formal dining room or area is a separate room that is designed for that purpose. Informal dining areas are usually attached to or part of the kitchen itself, and may take the form of a nook or alcove.
The main considerations for the dining area are that it should be large enough to accommodate a dining table and chairs (including room to get in and out of the table), and it should have easy access to the kitchen so that food does not have to be carried through other areas of the house.
6. Bedrooms
The number of bedrooms has a major effect on house value.
Normally, homes with different numbers of bedrooms appeal to different segments of the market, that is, to families of different sizes or lifestyles. The average household size in the market will have a large impact on the desirability of three- or four-bedroom homes, as opposed to two-bedroom homes.
Ideally, bedrooms should all be located in a separate sleeping zone, to provide both privacy and noise insulation. The most common arrangement is to locate the bedrooms on a separate story or wing. Each bedroom should have convenient access to a bathroom, either directly or via a private hallway. Also, it should not be necessary to go through a bedroom to reach another room (other than a private bath).
Depending on the room layout, a size of 9’ x 10’ is the minimum needed to allow for a single bed, 10’ x 12’ for a double bed. Whether larger room sizes will add to value depends on local market preferences. Most homes have at least one bedroom that is larger than the others, the MASTER BEDROOM. Modern master bedrooms will often have walk-in closets and other amenities.
Each bedroom should have its own closet. Most building codes require that bedrooms have a closet area of at least four square feet, 2’ x 2’ for example. The value of bedroom closets can be substantially increased by adding racks and drawers, shelving, shoe racks, and mirrored doors.

7. Bathrooms
   The number and location of bathrooms has a big influence on property value. Most homes have at least one bathroom for every two bedrooms. For a family of four, a single bathroom would be considered a major deficiency, while a home with four bathrooms might be considered an over-improvement.
   There are various types of bathrooms: a FULL BATH contains a sink, toilet, and bathtub (with or without a shower). THREE-QUARTER BATHS have a sink, toilet and shower, but no tub, and HALF BATHS or POWDER ROOMS have only a toilet and sink. The minimum size for a full bath is about 5’ x 8’, or 40 square feet. Additional space is needed for the vanity and storage cabinet, for the toilet (30” x 60” of space), and for the bathtub/shower (30” x 60” is needed for a shower, 30” x 72” for a tub/shower combination).
   Bathrooms should be located so that they are convenient and accessible from the bedrooms, as well as the living and working areas of the house. If the house contains more than one bathroom, it is preferable for one to be convenient to the main living areas for use by guests, and the other(s) for use by the home’s occupants.
   In houses with three or more bedrooms, at least one bathroom should be directly accessible from the master bedroom. This design provides the occupants of the master bedroom with a private master bath. Bathrooms should also be well ventilated, to allow steam to escape and to discourage mildew growth. Bathrooms without exterior windows should have an exhaust fan that vents directly to the outside.

IV. Construction Methods and Materials
An appraiser has to understand building material characteristics.
To arrive at an opinion of value, appraisers must describe the materials used in construction, including their quality and condition. The following sections discuss basic construction methods and materials.
A. Foundations
The FOUNDATION is that part of the building that rests on the soil and supports the rest of the structure. Foundation design must take into account❓ soil characteristics, potential for frost penetration and groundwater, and the weight of the structure and its contents. An inadequate foundation can result in cracked walls and ceilings, sticking doors and windows, and other structural problems that affect value.
1. Types of Foundations
A SLAB-ON-GRADE FOUNDATION (also known as a floating foundation, or MONOLITHIC SLAB FOUNDATION) consists of a single layer of concrete, poured directly on the ground. A slab-on-grade foundation must be at least four inches thick, and rest on a layer of compacted gravel to facilitate drainage. Because there is no excavated space between the foundation and the floor, slab-on-grade foundations are typically built only in areas where the ground never freezes.
A BASEMENT FOUNDATION has walls of poured concrete or concrete block that rest on a concrete footing below ground.
Basement foundations provide usable floor space below the first story of the house, and are common in areas with cold winters. With this type of foundation, the concrete walls must extend well below the frost line to prevent movement due to freezing and thawing cycles. They must also be waterproofed to prevent water from entering the basement.
To allow for proper drainage, the excavation must be graded away from the building, and it is usually necessary to provide a drainage system on the outside of the footing that carries excess water away from the foundation wall.
A CRAWL SPACE FOUNDATION has foundation walls similar to a basement foundation, but the walls do not extend as far below ground level. Crawl space foundations provide a space in which to run ductwork and pipes. They also allow access for repairs and pest control.
The disadvantage of a crawl space foundation is that the crawl space is typically unheated, so the floor above the crawl space can become very cold during the winter. For this reason, it is important to provide adequate floor insulation. Ventilation, and moisture-proofing of the walls are also important.
A PIER AND BEAM FOUNDATION consists of concrete piers, or posts, that rest on the ground and support wood or steel beams.
Houses with pier and beam foundations have a crawlspace, but they may or may not have a continuous foundation wall. This type of foundation is often used in areas where the soil is unstable, such as coastal regions subject to flooding or earthquake zones. The advantage of a pier and beam foundation is that it allows the building to be raised above ground level.
Another advantage of the pier and beam foundation is that it allows the building to be supported on a smaller number of load-bearing points, rather than having to bear the entire load on a continuous foundation wall. The disadvantage is that buildings with pier and beam foundations are more susceptible to wind damage.
2. Foundation Materials
Traditionally, foundations were made of stone, brick, or wood. Modern construction almost always utilizes reinforced concrete.
Foundation FOOTINGS are commonly concrete, six to twelve inches thick, and at least twice as wide as the foundation wall it supports. Rebar (steel reinforcing bars) are embedded in the concrete to add strength to the footing.
FOUNDATION WALLS can either be cast-in-place concrete or concrete block (cinder block). Cast-in-place concrete walls are formed and poured on site; after the concrete hardens, the forms are removed. Walls made of concrete block are built by stacking individual blocks and mortaring them together. Cast-in-place walls tend to be stronger, but are more costly to build.
B. Framing and Sheathing
FRAMING is the process of creating the structural skeleton of the building. SHEATHING is the application of exterior wall and roof coverings that support and protect the frame structure. The quality of the framing and sheathing is critical to the overall quality and durability of the house, as well as its energy efficiency.
A well framed house will have straight walls, level floors, and plumb doors and windows.
1. Framing Lumber
Traditional framing lumber is sawed from wood; modern construction also makes extensive use of engineered wood products, such as plywood, oriented strand board (OSB), waferboard and laminated wood. For wood that is used in locations that are exposed to moisture or insect damage (exterior wood, wood close to the ground, etc.), pressure treatment is used to force preservative chemicals into the wood.
Lumber is graded for quality by the lumber manufacturer, and the grade mark is stamped on the lumber. The grade indicates the allowable stress for that piece of lumber, as well as its moisture content. (The moisture content must be less than 19% for lumber to be considered “dry.”)
Lumber is identified by nominal dimensions in inches. For example, a 2 x 4 is nominally 2 inches thick and 4 inches wide. However, the actual dimensions are smaller than the nominal dimensions. A 2 x 4 actually measures about 1 ½ inches thick and 3 ½ inches wide. This is because the nominal dimensions are the original size of the lumber before it is dried and surfaced.
There are different types of lumber cuts, which are all rated by grade. Lumber grades range from “Select Structural” to “No. 3.” Select structural lumber has no knots or blemishes, and is usually used for construction that requires high strength. No. 3 grade lumber, which has large knots and blemishes, is typically used for non-structural members such as interior trim.
2. Framing Terminology
The terms used to describe the various components of the frame structure. The bottom horizontal member of a framed wall is called the SOLE PLATE (also called the SILL). Vertical framing members that support the wall are called STUDS. The top horizontal member of a framed wall is called the TOP PLATE.
A header is used to transfer the weight of the top plate to the adjoining studs around an opening for a window or a door.
The ceiling is supported by JOISTS, which are horizontal framing members resting on the top plate, and running parallel to each other. Rafters are like joists, except that they support the roof rather than the ceiling. The roof rafters are connected to a ridge board at the top of the roof.
The sill is the wooden member that is bolted to the foundation wall and forms the base for the wood framing.
3. Framing Methods
There are three main methods of framing: balloon framing, platform framing and post and beam framing.
a. BALLOON FRAMING is the oldest method. It utilizes long studs that run continuously from the foundation to the roof. Floor joists are nailed to the studs, and provide some support for the walls.
Balloon framing is relatively strong because the long studs run continuously from foundation to roof. However, it is also more expensive because the long studs must be custom-cut and installed. In addition, the open stud channels within the walls can create a fire hazard, since they allow a fire to spread rapidly from floor to floor.
b. PLATFORM FRAMING is the most widely used method. In this method, each floor is framed separately. Studs for the first floor extend from the sill to the top plate. Subflooring is applied, creating a platform. Then the studs for the next floor are built directly on this platform. Each story or level is framed in this manner, story by story.
Platform framing is more economical, safer and easier than balloon framing. It is more economical because there is less waste. It is safer in case of fire, because the flooring automatically creates a fire stop between each floor. It is also easier to build than balloon framing, which requires custom cutting of the studs.
c. POST AND BEAM FRAMING has been around for centuries. In this technique, the house is supported by a framework of vertical posts and horizontal beams, which carry the weight of the structure. The posts and beams are typically widely spaced, with large panels or windows placed between them.
Post and beam framing is usually used for the exterior of the house only; interior walls are framed using conventional techniques. The interior can also be left completely open, without any walls, so that the entire living area is contained in a single open space. In the past, solid wood timbers were used for the posts and beams. Modern construction commonly utilizes laminated wood or steel.
a. Roof Framing
For residential construction, there are two main types of roofs: flat roofs and pitched roofs. Flat roofs are simple to build, but are only suitable for use in areas with very little rainfall. In other areas, the roof is given a slope or pitch to allow water to run off, so pitched roofs are far more common. There are many variations on pitched roof designs, and terminology also varies between different regions. However, most roofs can be described in terms of three components: the rise (vertical height), the span (horizontal distance covered), and the pitch (ratio of rise to span).
Case/Example: A roof has a rise of 5 feet over a span of 24 feet. The pitch is equal to the rise divided by the span, 5/24, which is equal to about 21 percent. If a roof is 21 percent or over (5/12), it is steep. If the roof has a slope of less than 21 percent, it is normal (3/12) and if it has less than 2.1 percent (1/12), it is shallow. A building professional should be consulted for more information regarding roofing slopes and pitches as well as what may or may not be acceptable to the local building authorities.
One type of pitched roof is the GABLE ROOF. This is the simplest and least expensive type of pitched roof. Gable roofs have a ridge running the length of the building, and two sides or slopes that meet at the ridge to form an inverted “v.” The pitch of the gable can range from nearly flat to very steep, depending on design preferences and climatic considerations.
Truss Roof Systems- A common type of gable roof consists of a series of trussed rafters, also known as TRUSS ROOF SYSTEMS which are constructed off site at a factory and delivered to the construction site. A trussed rafter or truss is a pre-fabricated framework of lumber designed to support the weight of the roof. Trusses are relatively simple to install, and do not require any interior load-bearing walls. However, trussed rafters are more susceptible to damage from high winds.
Another common type of pitched roof is the HIP ROOF. The hip roof also has a ridge running the length of the building, but unlike a gable roof, the hip roof slopes down from all four sides. The hip roof is self-bracing, and less susceptible to wind damage. Hip roofs are more complicated and costly to build than gable roofs.
A third type of roof is the Mansard Roof.
b. Chimneys, Stacks, and Vents
Modern construction standards and building codes require the installation of multiple chimneys, stacks, and vents within the structural framework of a property. Chimneys direct combustion by-products to the exterior, stacks ventilate plumbing systems, and vents exhaust attic and crawl space air. The quality of these venting systems, as well as the location of their exterior access points, is important to the appraisal process.

4. Sheathing
   After the frame structure has been built, it must be sheathed, meaning covered with an exterior skin to provide weather protection. WALL SHEATHING is commonly made of plywood, waferboard, or oriented strand board (OSB). Roof sheathing is usually plywood or OSB. Roof sheathing is applied horizontally on top of the roof rafters.
   C. Exterior Finishes
   After a house has been sheathed, an exterior finish is applied to provide weather protection and a more attractive appearance. The most common types of exterior finish include:
   Aluminum siding
   Asphalt siding
   Brick
   Cement based siding
   Stone
   Stucco
   Vinyl siding
   Wood siding (board, shingles, plywood)
   A major factor in the desirability of any of these exterior finishes is how well they withstand the effects of the local climate. Wood is easily worked and attractive, but in wet or humid climates, it tends to decay unless it is well-protected by paint or other preservatives. Brick and stone are durable and require relatively little maintenance, but are more expensive and labor intensive to install. Vinyl siding is inexpensive and virtually maintenance-free, but is not as visually attractive as other finishes.

D. Doors and Windows
FENESTRATION is the arrangement and proportioning of windows and doors in a building. The quantity, size, and placement of doors and windows all contribute to the building’s overall design and appeal. Doors and windows must also provide weather protection and allow adequate light, ventilation and access.
1. Doors
Exterior doors should be solid, weather tight, and at least 2’ 8” wide and 6’ 8” high (32” x 80”). In addition, glass doors or doors with glass panels must use safety glass, which will not shatter into sharp pieces. Interior doors can be either solid or hollow-core. Hollow-core doors are cheaper, but do not provide as much insulation or noise reduction as solid-core doors.
The side and top pieces of the door frame are called JAMBS.
There are two types of doors: swing doors, where the door is hinged on one side, and sliding doors, where the door slides open and closed. For most interior doors, swing doors are the norm. Both types of doors are common for exterior access.
Door quality ranges from wood hollow core with basic hardware to solid core wood doors to metal fire resistant doors.
2. Windows
The number, location, and size of windows greatly affect the amount of natural light available in a home, as well as ventilation. Like doors, window frames are usually made of wood, aluminum, or vinyl. Window types are classified based on how the window opens:
Awning: Hinged at the top; swings outward
Casement: Hinged at the side; swings outward
Fixed: Does not open
Horizontal Slider: Slides open from side to side
Jalousie: Made of overlapping horizontal glass slats that pivot open and closed in unison
Single/Double Hung: Two sashes; the bottom sash slides up, the top sash slides down
Picture: Does not open, large single pane provides a scenic view
Skylight: Mounted on roof; fixed or vented
A major factor in the performance of windows is whether they are single or multiple pane (double or triple pane). MULTIPLE PANE windows have two or more sheets of glass that are separated by a small space. This arrangement greatly reduces heat loss in the winter, and heat gain in the summer.

E. Insulation
Insulating materials act as a barrier to heat flow, which reduces winter heating costs and summer cooling costs. The insulation is rated by its R-value, a measure of thermal resistance, or the ability to resist heat transfer. The higher the R-value, the better the material is at resisting heat transfer. Insulating value depends on type, thickness and density of the material.
Different areas of the house should be insulated to different R-values. Ceilings and attics are typically insulated to R-38 or more, walls to R-19, and floors to R-13. The location and amount of insulation varies depending on local climate and codes. Some common types of insulating materials include:
Blanket: Made of fiberglass or rock wool. Comes in rolls that are installed between studs, joists, or rafters.
Loose-fill: Made of cellulose, fiberglass, or rock wool. Can be blown into enclosed cavities, or poured into open ones.
Rigid Board: Made of polystyrene, polyurethane, fiberglass, or other materials. Comes in boards