Cost Segregation Studies: When the Math Works for Real Estate Investors
Cost segregation can accelerate $50K-$500K of depreciation in a single year. The breakeven property size and how the bonus-depreciation phase-out changes the math.
Cost segregation reclassifies a real-estate investment's components from the standard 27.5-year (residential) or 39-year (commercial) depreciation schedule into shorter-life classes. The result: accelerated first-year deductions, often $50K-$500K of depreciation that would otherwise spread over 30+ years.
What gets reclassified
An engineering study analyzes the building and identifies components that qualify for shorter depreciation lives:
5-year property: carpet, vinyl flooring, decorative lighting, specialty plumbing, removable wall finishes.
7-year property: cabinets, certain decorative woodwork, specific equipment.
15-year land improvements: sidewalks, parking lots, fencing, landscaping.
The remaining 27.5/39-year structural elements (foundation, framing, roof, HVAC core) stay on the standard schedule.
The first-year impact
For a $1M residential rental in 2024 with no cost seg: $1M / 27.5 = $36,364 first-year depreciation. With cost seg identifying 25% of the cost ($250K) as 5/15-year property, plus 60% bonus depreciation on the reclassified portion: ~$150K first-year depreciation, plus the standard $27K on the remaining $750K real-property basis. Total first-year deduction: ~$177K vs. $36K without cost seg.
Bonus depreciation phase-out matters
TCJA bonus depreciation is phasing out: 60% (2024), 40% (2025), 20% (2026), 0% (2027). The first-year benefit of cost seg compresses as bonus drops. Practitioner advice in 2026: still worthwhile for properties placed in service this year, much less attractive for 2027+ placements unless legislation extends bonus.
Recapture at sale
All depreciation taken — including cost-seg-accelerated portions — is subject to 25% recapture at sale. Cost seg is a tax-deferral, not a tax-elimination, strategy in the absence of further planning.
Two ways to avoid recapture: (1) 1031 exchange into another investment property, deferring recapture and gain. (2) Hold until death; basis steps up under §1014 and recapture is wiped out for heirs. Many active investors run a serial cost-seg + 1031 cycle for decades, then bequeath at death.
When cost seg pays off
Three conditions: (1) building basis above $500K-$750K, (2) you have other passive or active rental income to absorb the accelerated deduction (passive-activity-loss rules limit application), (3) you plan to hold long enough or 1031 to avoid recapture penalty.
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Frequently asked
An engineering-based study that reclassifies portions of a building's cost from 27.5/39-year real-property depreciation into shorter-life components: 5-year (carpet, decorative lighting), 7-year (cabinets, decorative trim), and 15-year (land improvements like sidewalks, parking lots). Each shorter class also qualifies for bonus depreciation when applicable.
Typically $5,000-$15,000 for a single-property study. Multi-property portfolios are cheaper per-property. Engineering firms specializing in cost seg are the typical providers; CPA firms with engineering teams also offer it.
Common practitioner threshold: $500K-$750K minimum building value (excluding land). Below that, the study cost relative to first-year depreciation acceleration usually doesn't justify the engagement. Above $1M, the math is almost always favorable.
Bonus depreciation phase-out under TCJA: 60% in 2024, 40% in 2025, 20% in 2026, 0% in 2027. The 5/7/15-year components reclassified by cost seg can be deducted at 60%/40%/20% bonus in their first year. As bonus phases out, cost seg's first-year impact diminishes — but the underlying acceleration still helps.
Yes — depreciation taken (whether normal or accelerated via cost seg) is subject to 25% recapture at sale. A 1031 exchange defers both recapture and capital gain. Death-with-step-up wipes both out entirely. Many active investors plan cost-seg-then-1031 cycles.
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