Interior Components and Systems

Chapter Title: Interior Components and Systems

Introduction

This chapter provides a comprehensive overview of the interior components and systems found within buildings. A thorough understanding of these elements is crucial for appraisers to accurately assess a property’s condition, functionality, and value. We will delve into the scientific principles governing their performance, construction methods, and potential issues.

1. Interior Supports

Interior supports are structural elements designed to transfer loads from the upper parts of the building to the foundation. Their integrity is paramount for the overall stability and safety of the structure.

1.  **Beams, Columns, and Trusses**

    *   These elements work together to support floor and roof loads, particularly when spans exceed the capacity of joists.

    *   **Beams:** Horizontal structural members designed to resist bending moments.
        *   Bending Moment (M):  M = (w * L^2) / 8  (for a simply supported beam with uniformly distributed load), where w = load per unit length, and L = beam span.
        *   **Practical Application:** Observing deflection in beams can indicate overloading or material degradation. An experiment could involve loading a small-scale beam model to observe its deflection under increasing weight.

    *   **Columns:** Vertical structural members designed to resist compressive forces.
        *   Critical Buckling Load (Pcr) for a column: Pcr = (π^2 * E * I) / (L^2), where E = Modulus of Elasticity of the material, I = Area Moment of Inertia, and L = Effective length of the column.
        *   **Practical Application:** Inspect columns for signs of buckling or crushing, which indicate a compromised load-bearing capacity.

    *   **Trusses:**  Structural assemblies composed of interconnected members arranged in triangles to distribute loads efficiently.  They are often used to span large distances.
        *   **Scientific Principle:** The triangular geometry of a truss allows it to distribute loads axially, minimizing bending stresses in the individual members.
        *   **Practical Application:**  Trusses are commonly used in roof and floor systems. Their inspection involves checking for damaged or missing members, and loose connections.

    *   **Materials:** Common materials include wood, steel, masonry, and concrete. Each material has unique properties affecting load-bearing capacity and durability.

        *   **Wood:**  High strength-to-weight ratio, but susceptible to decay and insect damage.
        *   **Steel:**  High strength and ductility, but vulnerable to corrosion.
        *   **Concrete:**  High compressive strength, but low tensile strength.
        *   **Masonry:**  Good compressive strength and fire resistance.

    *   **Inspection:** Cracked or sagging beams, as well as columns exhibiting signs of crushing or buckling, are critical issues that should be documented.
2.  **Flooring System**

    *   The flooring system provides a stable and level surface for occupants and furnishings. It consists of subflooring and finished flooring.

    *   **Subflooring:** Provides a base for the finished floor material. It should be strong enough to support loads without excessive deflection.
        *   Materials: Typically wood (plywood, OSB) or concrete.
        *   **Scientific Principle:** Deflection is directly proportional to the applied load and inversely proportional to the material's stiffness and the subfloor's thickness.
        *   **Practical Application:**  Check for spongy or uneven areas in the floor, which may indicate subfloor damage.

    *   **Bridging:**  Used to stiffen joists and prevent them from twisting or deflecting under load.
        *   **Scientific Principle:**  Bridging distributes the load across multiple joists, reducing stress on any single joist.

    *   **Finished Flooring:**  The visible surface of the floor.
        *   Materials: Wood, tile, carpet, resilient flooring (vinyl, laminate).
        *   Considerations: Durability, aesthetics, and compatibility with the building's design and intended use.

2. Division of Space

The layout and partitioning of interior spaces significantly impact a property’s functionality and value.

1.  **Walls**

    *   **Residential Buildings:** Typically wood studs covered with drywall (gypsum board), plaster, or wood paneling.
        *   **Drywall (Gypsum Board):**  Composed of a gypsum core sandwiched between paper facings. Provides fire resistance and a smooth surface for finishing.
        *   **Fire Resistance:** Gypsum releases water when exposed to fire, slowing down the spread of flames.
    *   **Commercial Buildings:** May use wire partitions, glass, wood, plywood, hardboard, metals, tile, concrete, or solid masonry walls for fire protection.
    *   **Partitions:** Generally non-load-bearing and movable.
        *   Materials: Various materials, including metal studs and drywall, wood, or composite panels.

    *   **Considerations:**
        *   Load-bearing vs. non-load-bearing walls. Removing load-bearing walls can compromise the structural integrity of the building.
        *   Fire resistance requirements, especially in commercial buildings.
        *   Sound insulation properties.
2.  **Doors**

    *   **Types:** Hollow-core (residential), solid-core (older buildings, offices), fire-resistant (commercial/industrial), specialty (self-opening/closing).
    *   **Hollow-Core Doors:**  Lightweight and inexpensive, but offer limited security and sound insulation.
    *   **Solid-Core Doors:**  Provide better security, sound insulation, and fire resistance.
    *   **Fire-Rated Doors:**  Designed to resist fire and smoke for a specified period.
        *   **Scientific Principle:**  Intumescent seals expand when exposed to heat, sealing the gap between the door and frame to prevent the passage of smoke and flames.
    *   **Inspection:** Poorly hung doors that do not close properly or fail to seal the frame are common issues.
3.  **Ceilings**

    *   Materials: Gypsum board, plaster, tile, suspended panels (drop ceilings), or the underside of the upper floor.
    *   **Suspended Ceilings:**  Consist of a grid of metal runners suspended from the structure above, with panels inserted into the grid. They conceal mechanical and electrical systems and provide acoustic control.
        *   **Acoustic Control:**  Acoustic ceiling tiles absorb sound energy, reducing reverberation and noise levels. The Sound Absorption Coefficient (SAC) measures the amount of sound absorbed by a material.
    *   **Ceiling Height:**  Can affect the perceived spaciousness of a room and can impact property value if it deviates significantly from market norms.
        *   **Functional Obsolescence:** Ceilings that are too high or too low for the property’s current highest and best use may be considered items of functional obsolescence.

3. Stairs, Ramps, Elevators, Escalators, and Hoists

These elements provide vertical circulation within a building.

1.  **Stairs and Ramps**

    *   **Residential Buildings:** Provide safe ascent and descent, with adequate headroom and space for moving furniture and equipment.
    *   **Public Buildings:** Codes regulate the design and construction of stairs, including their location, enclosure for fire protection, and accessibility for people with disabilities.
    *   **Accessibility:**  The Americans with Disabilities Act (ADA) mandates accessibility standards for public accommodations, which may require ramps, elevators, or other special equipment.

        *   **ADA Requirements:** Maximum slope for ramps is 1:12 (1 inch of rise for every 12 inches of run).

    *   **Building Codes:** Dictate minimum and maximum tread and rise dimensions for stairs. Uniformity in tread and rise is essential for safety.

        *   **Rise (R):** Vertical distance between treads.
        *   **Tread (T):** Horizontal distance between risers.
        *   **Rule of Thumb:** 2R + T = 24 to 25 inches (a common guideline for comfortable stair design).

2.  **Elevators, Escalators, and Hoists**

    *   **Multistory Buildings:** Efficient elevators and escalators are crucial for moving people and freight.
    *   **Hydraulic Elevators:**  Use oil lines and cylinders in the ground; leaks can go undetected.
    *   **Special Elevators and Hoists:**  Often considered part of the building, but may be studied under the equipment category.
    *   **Capacity and Speed:**  Elevator capacity and speed should be adequate for the building's occupancy and use. Inadequate elevator service can lead to delays and tenant dissatisfaction.

4. Interior Painting, Decorating, and Finishing

These elements affect the aesthetic appeal and perceived value of a property.

1.  **Painting and Decorating**

    *   Attractiveness is subjective, but unusual decorations and colors may have limited appeal.
    *   Quality of decoration is important in valuing restaurants, stores, and other commercial buildings.
2.  **Basement Finishes**

    *   Unfinished basements are used for storage.
    *   Finished basements are used for storage and other purposes (in residences and some commercial buildings).
    *   Dampness is a common problem in basements. Signs of dampness include powdery white mineral deposits, stains, and the smell of mildew.

        *   **Causes of Dampness:** Poor foundation wall construction, excess groundwater, poorly fitted windows, poor venting, or poorly constructed roof drains.
3.  **Flooring and Floor Coverings**

    *   A wide variety of flooring is available. Some flooring materials are selected primarily for their low cost and durability.
    *   Consider how floor coverings endure wear and tear and how they conform to a building’s design and decoration.
    *   **Types:**
        *   Sand, compressed dirt, bituminous paving, brick, stone gravel, concrete (suitable for industrial buildings, warehouses, garages, and basements).
        *   Terrazzo flooring (used for high-traffic areas such as lobbies of public buildings).
        *   Wood (popular material for floors).
        *   Resilient, ceramic, stone, and quarry tiles (used in all types of buildings).
        *   Carpeting (widely used in all types of buildings).
4.  **Interior Wall Coverings and Ceilings**

    *   **Walls and Partitions:** May be painted, papered, or paneled. Supplemental finishes include ceramic tile and wainscot paneling.
    *   **Ceilings:** Can be drywall, plaster, or suspended panel (drop ceilings).

5. Protection Against Decay and Insect Damage

Wood is susceptible to decay and insect damage.

1.  **Decay**

    *   Caused by fungi that thrive in moist environments.
    *   **Prevention:**
        *   Sloping the ground away from foundations for good drainage.
        *   Using vapor barriers on the interior sides of exposed walls.
        *   Using polyethylene as a soil cover in crawl spaces.
        *   Flashing, gutters, downspouts, and splash blocks to carry water away from foundation walls.
        *   Using poured concrete foundation walls, concrete caps over unit masonry foundations, wood treatments, soil treatments, or metal termite shields.
        *   Building with dry, naturally durable woods.
        *   Conducting regular maintenance inspections.
2.  **Insect Damage**

    *   Termites are the most destructive insects to both damp and dry wood.
    *   **Prevention:**
        *   Same as decay prevention.
        *   Soil treatments to create a barrier against termites.
        *   Metal termite shields to prevent termites from reaching wood.
3. **Irrigation Systems**

    * Improperly aimed lawn irrigation systems can cause water to collect against the foundation or be directed at exterior walls or windows. This can lead to rot and mold problems.

6. Equipment and Mechanical Systems

Major equipment and mechanical systems include the plumbing, HVAC, and electrical systems.

1.  **Plumbing System**

    *   Consists of supply, waste, and vent piping and fixtures and fittings.
    *   **Piping:**
        *   Supply pipes: Copper, cast iron, or plastic.
        *   Waste pipes: Copper, cast iron, or plastic.
        *   Vent pipes: Copper, cast iron, or plastic.
        *   Galvanized steel, lead, or brass pipes in older buildings may need to be replaced.
    *   **Fixtures:**
        *   Bathroom fixtures: Lavatories, bathtubs, showers, toilets, bidets, urinals.
        *   Kitchen fixtures: Sinks, garbage disposals, dishwashers.
        *   Other fixtures: Instant hot water units, laundry tubs, wet bars, swimming pools or saunas, janitor sinks, drinking fountains, handwashing and eye-washing fountains.
    *   **Fittings:** Faucets, spigots, drains, shower heads, spray tubes, floor drains.
    *   **Water Hardness:** Hard water contains minerals that react unfavorably with soap and make it difficult to rinse.

Conclusion

A thorough understanding of interior components and systems is crucial for accurate property appraisal. This chapter has provided a foundation in the scientific principles, construction methods, and potential issues related to these elements. By applying this knowledge, appraisers can better assess a property’s condition, functionality, and value.