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How are Residential Buildings and Properties Measured for Property Assessment Purposes?
When assessing residential properties, it's important to know how they are measured to determine their value. The problem often lies in the complexity of measurement methods, which can affect how property size and value are calculated. To address this, homeowner should learn about the standard methods used to measure residential buildings, including the key factors that are considered and how different areas are included or excluded. This understanding will help you grasp how property assessments are made and ensure accurate evaluations.
Ensuring Consistency and Accuracy in Property Valuation
In the U.S. real estate market, measuring residential buildings consistently and accurately is crucial for determining property values. To achieve this, several key organizations and standards guide the measurement practices used nationwide.
ANSI Z765-2021: A Standard for Uniform Measurement
Fannie Mae, a major mortgage provider, adopted the ANSI Z765-2021 standard starting April 1, 2022. This standard outlines how to measure and report both the Gross Living Area (GLA) and other areas of residential properties. The goal is to ensure that square footage is measured consistently across all homes, reducing discrepancies and improving confidence in property valuations.
BOMA Standards: For Mixed-Use and Commercial Properties
The Building Owners and Managers Association (BOMA) provides measurement standards mainly for commercial properties, but these can also apply to mixed-use or multifamily residential buildings where commercial and residential spaces overlap.
International Property Measurement Standards (IPMS): A Global View
The International Property Measurement Standards (IPMS) offer a global approach to measuring properties. These standards help ensure consistent and transparent measurements across various property types, including residential, commercial, and industrial. For U.S. investors or homeowners looking at international markets, understanding IPMS can enhance their knowledge and confidence in property valuations abroad.
Exterior and Interior Measurements
Exterior Measurement (IPMS 1)
Measuring a building's external boundaries, known as the Gross External Area, is key for planning and budgeting in development projects. Here’s how the International Property Measurement Standards (IPMS) 1 guides this process.
Measurement Process
The Gross External Area measures the total space covered by the building, including its outer walls. Measurements are taken for each floor, extending to the outer faces of external features to provide a complete view of the building's size and layout.
Typically, measurements are obtained from architectural plans or directly on-site. If detailed plans are not available, estimates for wall thickness are used to ensure accuracy.
For specific features like roller shutters and openings, measurements follow the external boundary line to maintain precision. Adjustments are made for buildings with unique structures, focusing on covered areas such as canopies.
In the case of attached or semi-detached homes, measurements are taken from the centerline between units. For multi-unit buildings, distinctions are made between areas designated for exclusive use and those that are shared.
Inclusions and Exclusions
1. Inclusions. The Gross External Area covers all usable spaces within the building, including walls, columns, and enclosed passages. Features such as balconies and verandas are measured separately.
2. Exclusions. Certain elements are not included in the Gross External Area, such as temporary mezzanines, open light wells, and external spaces like parking lots and patios. These exclusions help focus on the building's enclosed space, with additional measurements taken for other structures or ground-level areas outside the main covered space.
CityStructure Analysis calculates the maximum building area allowed on your property.
Diagram 1: IPMS 1 – Residential Ground Floor (Level 0)
IPMS 1 measures the total area of each floor level of a building, extending to the outer face of external features. This includes spaces like atria, but only at their lowest floor level.
Measurements can be detailed for each component of the building if needed. The total area calculated from all components should align with the IPMS 1 measurement. If basement plans aren't available, the measurement should include an estimate of the exterior wall thickness.
Diagram 2: IPMS 1 – Residential First Floor (Level 1)
IPMS 1 refers to the total area of each floor level in a building, measured up to the outer face of external construction features.
Spaces like atria are included only at their lowest floor level.
If needed, IPMS 1 measurements can be detailed for each component of every floor in the building.
The sum of all component areas should match the IPMS 1 measurement. If basement plans are missing, the area should include an estimate of the exterior wall thickness.
Diagram 3: IPMS 1 – Residential Second Floor (Level 2)
IPMS 1 measures the total area of each floor level in a building, extending to the outer face of external construction features.
Covered void spaces, such as atria, are counted only at their lowest floor level.
When needed, IPMS 1 measurements can be broken down by component for each floor of the building.
The total of all component areas should match the IPMS 1 measurement. If basement plans are missing, the measurement should include an estimate of the exterior wall thickness.
Interior Measurement (IPMS 2)
Interior measurement for residential buildings involves determining the internal space within a structure. This type of measurement helps with understanding space usage, setting benchmarks, and marketing. It allows comparisons of floor space between different buildings, aiding users, third parties, and service providers in making informed decisions.
Definition
IPMS 2 – Residential measures the total floor area within a building, up to the Internal Dominant Face (IDF) of the external walls. This can be reported for each floor, detailing component by component if needed.
Measurement Practice
IPMS 2 – Residential measurements cover the space up to the Internal Dominant Face (IDF) for external features and extend to the Finished Surface for other areas. External walls play a key role in this measurement.
Measurements can be specified for each floor on a component-by-component basis. The combined total of these individual component areas, excluding the external wall area, should align with the overall IPMS 2 – Residential measurement.
In multi-unit buildings, measurements can distinguish between areas used exclusively by residents and shared common areas. This separation helps provide a clear understanding of space allocation.
Inclusions and Exclusions
1. Inclusions. IPMS 2 – Residential includes all space within the IDF, such as internal walls, columns, and enclosed passages. Covered void areas, like atria, are only included at their lowest floor level. Features like balconies and verandas are included but reported separately, measured to their Finished Surface.
2. Exclusions. IPMS 2 – Residential does not include temporary mezzanines, open light wells, and upper-level voids in atriums. Ground-level areas outside the External Wall, like sheltered areas and loading bays, are also excluded but may be measured and reported separately if needed.
Diagram 1: IPMS 2 – Residential Ground Floor (Level 0)
IPMS 2 – Residential measures the total area of each floor level within a residential building, up to the Internal Dominant Face (IDF).
For this measurement, areas are measured to the IDF for external construction features and to the Finished Surface for other parts.
Void areas like atria are only included at their lowest floor level.
If needed, measurements can be detailed on a component-by-component basis for each floor. The sum of these component areas, excluding the external wall area, should match the overall IPMS 2 – Residential measurement.
Diagram 2: IPMS 2 – Residential First Floor (Level 1)
IPMS 2 – Residential measures the total area of each floor in a residential building, extending up to the Internal Dominant Face (IDF).
For IPMS 2 – Residential, measurements are taken to the IDF for external features and to the Finished Surface for other areas.
Covered voids like atria are included only at their lowest floor level.
If needed, measurements can be broken down by each component for every floor. The total of these component areas, excluding the external wall area, should match the IPMS 2 – Residential measurement.
Diagram 3: IPMS 2 – Residential Second Floor (Level 2)
IPMS 2 – Residential measures the total area of all floors within a residential building, up to the Internal Dominant Face (IDF).
For IPMS 2 – Residential, measurements reach the IDF for external construction features and the Finished Surface for other parts.
Covered voids, such as atria, are included only at their lowest floor level.
When needed, measurements can be broken down by component for each floor. The total of these component areas, excluding the external wall area, should match the IPMS 2 – Residential measurement.