🇺🇸 Made in America·100% U.S.-Based Team · 24+ Years in Cost Segregation
A developer named Rachel was building a $14 million medical office complex in Tampa in 2024. A real estate investor named Marcus had just closed on a $14 million existing office building in Atlanta the same month. Both reached out to the Cost Seg America team about cost segregation studies. Both expected to save substantial federal tax in Year 1. Both did.
But the methodology for Rachel's new construction project was fundamentally different from the methodology for Marcus's acquired property. The reports they received told the same story (cost segregation produces large Year 1 deductions) through different documentary frameworks. The fee was different. The timeline was different. The kinds of documentation each one received was different. And the answers to several common questions were different.
This article walks through what changes between cost segregation on new construction and cost segregation on acquired property. The math at the end of the analysis is similar (both Rachel and Marcus claimed roughly $4 million of Year 1 deductions). The path to that math is meaningfully different. Property owners considering either scenario should understand the distinction before commissioning a study.
The IRS Cost Segregation Audit Technique Guide (Publication 5653, current edition dated February 6, 2025) identifies six possible methodologies for performing a cost segregation study, labeled Approaches 1 through 6. The Guide explicitly names Approaches 1 and 2 as preferred because they produce the strongest component-level documentation. The other four methodologies (surveys, residual estimation, sampling, rule of thumb) are recognized but produce weaker documentation that is more vulnerable on IRS examination.
The two preferred approaches correspond directly to the new construction vs acquired property distinction:
Approach 1: Detailed Engineering Approach from Actual Cost Records. This methodology applies when actual construction cost records are available. The cost segregation engineer takes the contractor invoices, change orders, payment requests, architect drawings, and other documented construction costs, and assigns every documented cost to its proper MACRS class based on the underlying engineering analysis. Each classification is tied to a specific invoice or cost record.
Approach 2: Detailed Engineering Cost Estimate Approach. This methodology applies when actual construction cost records are not available (typical for acquired property). The cost segregation engineer performs an engineering analysis of the property, measures and documents every component, and builds cost estimates using the Replacement Cost New Less Depreciation methodology supported by industry-standard cost references (Marshall Valuation Service, R.S. Means, and similar published cost data).
Both approaches produce defensible component-level analysis that holds up on IRS examination. The choice between them is determined by what documentation is available, not by the property owner's preference.
The Cost Seg America team has been performing engineered cost segregation studies using both Approach 1 and Approach 2 on every study for more than 24 years. 16,000 studies. 125 IRS audits defended. Zero losses. $0 ever returned to the IRS. The average first-year savings across the 16,000+ completed studies is $438,511. Every study is engineered, not estimated. Made in America, by Americans. Approach 1 on new construction. Approach 2 on acquired property. The IRS-preferred methodologies, applied to whichever circumstance applies to the specific property.
New construction is the cleanest scenario for cost segregation because the underlying documentation is created during the construction process itself. Every dollar spent on the project generates a record (contractor invoice, subcontractor payment, change order, supplier receipt) that ties the cost to a specific scope of work.
The Approach 1 methodology takes that existing documentation and reorganizes it into MACRS class lives. The process looks like this:
Phase 1: Cost records review. The cost segregation firm reviews every available construction cost record. Contractor payment applications. Subcontractor invoices. Change orders. Direct purchases by the owner. Architect and engineering fees. Site work costs. Equipment installation costs. Every dollar gets traced back to its source document.
Phase 2: Construction Specifications Institute classification. The documented costs get sorted by Construction Specifications Institute (CSI) divisions: Division 03 Concrete, Division 04 Masonry, Division 05 Metals, Division 07 Thermal and Moisture Protection, Division 08 Doors and Windows, Division 09 Finishes, Division 14 Conveying Systems, Division 15 Mechanical, Division 16 Electrical, and similar. This division-based organization establishes the audit trail from the contractor payment requests through to the final tax classification.
Phase 3: MACRS classification through the Whiteco analysis. Each cost element gets analyzed under the Whiteco 6-factor test (Whiteco Industries v. Commissioner, 65 T.C. 664, 1975) to determine whether it qualifies as Section 1245 tangible personal property or Section 1250 real property. The classification is supported by specific reference to the actual installation, the design intent, and the attachment method documented in the construction records.
Phase 4: Report production. The completed study contains the three core schedules: Project Cost Summary (total costs by CSI division), Component Unit Summary (every reclassified component grouped by MACRS class), and Component Unit Detail (every individual cost element with the supporting source document referenced). The report ties every line item back to a specific construction record.
The fee on new construction studies. Approach 1 studies typically run lower fees than Approach 2 studies because the underlying cost records do most of the work. The cost segregation engineer is organizing and analyzing existing documentation rather than building cost estimates from an engineering analysis. The fee depends on the complexity of the project and the volume of records to review, but Approach 1 is generally the more efficient methodology.
The timing on new construction studies. Approach 1 studies are typically commissioned during construction or shortly after substantial completion. The construction records are fresh, the contractors are still available to answer questions, and the timeline aligns naturally with the property being placed in service. The completed report is ready for the first tax return that includes the new property.
Acquired property is the more common scenario in commercial real estate. Most cost segregation studies are performed on buildings that the current owner did not build themselves. The original construction records may be decades old, partially lost, or simply unavailable to the current owner.
Approach 2 handles this circumstance by building cost estimates from a physical engineering analysis of the property as it stands today. The process looks like this:
Phase 1: Documentation review. The cost segregation firm pulls every available document on the property. Purchase contract and HUD-1 settlement statement. Property tax records showing the assessor's allocation between land and improvements. Appraisal reports if available. Any construction documentation that came with the property at closing. Architect drawings if any survived. Each of these informs the analysis.
Phase 2: Engineering analysis. This is the defining step of Approach 2. A qualified engineer performs the engineering analysis on the property, evaluating every relevant component, dimension, and system. The analysis identifies the installation method, attachment method, and condition of each item from available construction records, design documentation, plans, and property specifications. The engineering analysis typically takes one to two days depending on the property size and complexity. Without the engineering analysis, the study is not running Approach 2.
Phase 3: Cost estimate construction (RCNLD methodology). The Replacement Cost New Less Depreciation methodology builds an estimate of what each documented component would cost to replace today using industry-standard cost data. Marshall Valuation Service and R.S. Means Facilities Construction Cost Data are the most commonly used cost references. The cost estimate is then adjusted down for accrued depreciation to arrive at the Replacement Cost New Less Depreciation figure. This is the cost basis allocated to that specific component.
Phase 4: MACRS classification through the Whiteco analysis. Each documented component, with its supported cost estimate, gets analyzed under the Whiteco 6-factor test to determine whether it qualifies as Section 1245 personal property or Section 1250 real property. The classification is supported by specific reference to the observed installation, the design intent, and the attachment method documented during the engineering review.
Phase 5: Report production. The completed study contains the same three core schedules as a new construction study: Project Cost Summary, Component Unit Summary, and Component Unit Detail. The Component Unit Detail in an Approach 2 study includes the cost source for each item (Marshall Valuation Service, R.S. Means, engineering estimate, etc.) instead of the contractor invoice reference used in an Approach 1 study.
The fee on acquired property studies. Approach 2 studies typically run higher fees than Approach 1 studies because the work involves an engineering analysis of the property, cost estimate development from published references, and engineering analysis of each component based on observed conditions. The fee scales with property size and complexity, but the methodology is more labor-intensive than the construction-records-based approach.
The timing on acquired property studies. Approach 2 studies can be performed at any time after the property is placed in service. Most are commissioned in the year of acquisition, but lookback studies on properties acquired in prior years are also common. The Form 3115 process allows the catch-up depreciation from prior years to be claimed in the current year when a lookback study is performed.
Several practical differences between Approach 1 and Approach 2 studies affect how a property owner should think about the work.
Documentation availability matters less than property owners often think. A common misconception is that without complete construction records, an acquired property cannot benefit from cost segregation. The opposite is true. Approach 2 was specifically designed for circumstances where construction records are unavailable. The engineering analysis and RCNLD methodology produce defensible classifications regardless of what construction documentation exists.
The Year 1 deduction is similar on both methodologies. A properly built study under either Approach 1 or Approach 2 produces similar percentage reclassifications. The methodology determines how the analysis is documented, not how much can be reclassified. A 30 percent reclassification rate on a new construction project produces the same percentage on an acquired version of a similar property.
The fee difference is meaningful but does not change the value calculation. Approach 2 studies typically cost more than Approach 1 studies on equivalent properties. Both fees are recovered many times over by the Year 1 tax savings on properties above the $250,000 threshold. The fee difference matters for the ROI analysis on smaller properties but rarely changes the decision to proceed.
The audit defense is identical regardless of methodology. A study built on Approach 1 and a study built on Approach 2 both contain the component-level analysis the IRS Audit Technique Guide describes. Both hold up on IRS examination when properly executed. The Cost Seg America team has defended 125 IRS audits across both methodologies without a single loss or returned dollar.
Whether you are building a new commercial property or acquiring an existing one, cost segregation works. The methodology differs (Approach 1 for new construction with records, Approach 2 for acquired property without records). The deduction outcome is similar. The audit defense is identical. The Year 1 federal tax savings on a typical commercial property in the $1 million to $10 million range run in the hundreds of thousands to seven figures regardless of which methodology applies.
The Cost Seg America team has performed Approach 1 and Approach 2 studies on 16,000+ properties over more than 24 years. 125 IRS audits defended. Zero losses. $0 ever returned to the IRS. The average first-year savings across those studies is $438,511. Every study uses the IRS-preferred methodology that fits the property's circumstances. Engineered, not estimated. Made in America, by Americans.
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