Cost Segregation Studies: How Miami Property Investors Turn a Building Into a First-Year Deduction
Armando Ramirez5 min read
Most real estate investors treat depreciation as background noise. You buy a building, your accountant spreads the cost over decades, and a modest deduction shows up on Schedule E every year until you sell. A cost segregation study rejects that premise. It says a building is not one asset, it is dozens, and many of them wear out far faster than the walls around them. Done correctly, a cost segregation study can compress twenty years of deductions into a single tax return.
In 2026, that compression is worth more than it has been in years.
What a Cost Segregation Study Actually Does
The default IRS schedule is blunt: commercial buildings depreciate over 39 years, residential rental property over 27.5 years. A cost segregation study, performed by engineers who inspect the property and price its components, separates out the pieces that do not belong on that long schedule.
Carpeting, cabinetry, appliances, decorative lighting, and specialty electrical serving equipment are typically 5-year personal property. Parking lots, fencing, landscaping, and site lighting are generally 15-year land improvements. The structure itself — the foundation, framing, roof, and core systems — stays on the long schedule.
That reclassification has always mattered. What changed is how quickly the reclassified pieces can be written off.
Why 100% Bonus Depreciation Changed the Math
Under the Tax Cuts and Jobs Act, bonus depreciation was phasing out on a set schedule, dropping to 40% for 2025, 20% for 2026, and zero after that. For smaller properties, that decay made studies hard to justify. Then the One Big Beautiful Bill Act, signed in July 2025, permanently restored 100% bonus depreciation for qualified property acquired and placed in service after January 19, 2025.
The critical link: bonus depreciation applies to property with a recovery period of 20 years or less, which is exactly what a cost segregation study pulls out of a building. The shell does not qualify. Everything the study reclassifies does.
| First-year treatment of reclassified assets | Old phase-down (2026) | Current law |
|---|---|---|
| Bonus depreciation rate | 20% | 100% |
| $500,000 reclassified | $100,000 deducted | $500,000 deducted |
| Status of the rule | Expiring after 2026 | Permanent |
One more detail that trips people up: the IRS looks to the binding contract date, not the closing date, when testing that January 19, 2025 threshold.
A Worked Example on a South Florida Rental
Picture an investor who closes on a small multifamily building in Miami for $2.4 million. Land accounts for $600,000, leaving a depreciable basis of $1.8 million. An engineering study breaks it down like this:
| Component category | What it covers | Recovery period | Allocated basis |
|---|---|---|---|
| Personal property | Appliances, flooring, cabinetry, fixtures | 5 years | $234,000 |
| Land improvements | Paving, fencing, landscaping, site lighting | 15 years | $270,000 |
| Building structure | Foundation, framing, roof, core systems | 27.5 years | $1,296,000 |
The $504,000 sitting in those first two rows is bonus-eligible and comes off in year one. Add the ordinary depreciation on the structure and the first-year picture looks very different:
| Scenario | Year-one depreciation | Federal tax saved at 37% |
|---|---|---|
| No study | roughly $65,000 | roughly $24,000 |
| Study plus 100% bonus | roughly $569,000 | roughly $211,000 |
Numbers are illustrative and ignore placed-in-service conventions, but the shape holds. And in Florida, where there is no state income tax to complicate the calculation, the federal savings are the whole story.
Against that, study fees are minor. Pricing commonly runs in the $5,000 to $15,000 range for commercial property, with lighter desktop studies available for smaller residential assets.
The Two Catches Nobody Should Skip
Passive activity loss limits. A large paper loss is only useful if you can deduct it against something. Real Estate Professional status lets investors apply these losses against other income immediately; without it, passive activity rules generally suspend the losses until there is passive income or a sale. Short-term rentals are the notable exception: when the average stay is seven days or less and the owner materially participates, the losses may be treated as non-passive — see the average-stay test and material participation hours that let a short-term rental's losses offset W-2 income — though the recordkeeping has to be real.
Depreciation recapture. Accelerating deductions does not erase them, it borrows against the sale. Section 1245 personal property is generally recaptured at ordinary income rates, while Section 1250 gain can be taxed at up to 25%. A foreign owner selling the property adds another layer on top of that recapture: FIRPTA withholding on the gross sale price, which applies regardless of what the recapture math actually owes. An investor planning to hold long term or exchange into another property is in a very different position than one flipping in three years.
Already Own the Property? Look Back
Missing the year of purchase is not fatal. A look-back study paired with a Form 3115 accounting method change lets an owner capture all the depreciation that should have been claimed in prior years and recognize it in a single current-year catch-up adjustment. No amended returns required. For anyone holding property bought in the last several years without ever running the numbers, this is often the largest deduction available on this year’s return.
The Takeaway
A cost segregation study is not a loophole, it is an engineering exercise the tax code explicitly permits, and with 100% bonus depreciation now permanent, the return on that exercise is at a multi-year high. The right question is not whether the strategy works. It is whether your hold period, your participation level, and your exit plan make front-loading those deductions the smart move for your portfolio. That conversation should happen before the next closing, not after.