🇺🇸 Made in America·100% U.S.-Based Team · 24+ Years in Cost Segregation
If you buy a rental, renovate it, rent it and hold it, the renovation is usually the most valuable part of the deal for tax purposes. A fully engineered and accounted cost segregation study separates the rehab spending and the purchase price into the pieces the tax code treats as 5-, 7- and 15-year property instead of one 27.5-year line, and for property acquired and placed in service after January 19, 2025, those pieces get 100 percent bonus depreciation in the first year the property is in service. Two catches come before the benefit: the loss is passive unless you are a real estate professional, the property is a short-term rental you materially participate in, or you fit the small-landlord allowance, and otherwise it carries forward. And if you buy, renovate and resell, the house is inventory rather than depreciable property, and no study helps a flip.
Marlene is a project manager at a software company in Burlington, Vermont, with a steady salary and three rentals on the side. In February 2026 she closed on a 1970s duplex on the south side for $400,000. The inspection was ugly: original kitchens, worn carpet, a failing fence, a cracked driveway. Her lender and her contractor agreed on a $120,000 renovation. The work finished the first week of June, both units were listed that week, and tenants signed by the end of the month.
Her purchase agreement and the county records supported $80,000 of the price as land. That left $320,000 of building. Add $120,000 of capitalized rehab and she had $440,000 of depreciable cost. Her tax preparer put all of it on the 27.5-year schedule, and in the year the duplex went into service that produced $8,668 of depreciation. Next to what she had spent, it felt like a rounding error.
A fellow investor asked her one question: "Did anyone look at what is actually inside the $440,000?" Cost segregation is the process of answering it. Marlene is illustrative; the rules and the arithmetic are real.
If the concept is new, the sections below start from the beginning, and the section on when a study does not make sense says whether the numbers justify one.
A study is an engineered analysis of what you bought and built, sorting every cost into its class under the Code and the regulations. On a residential rental, where the engineering supports it:
The IRS lays out what a defensible study contains in its Audit Techniques Guide, and the courts' test for separating personal property from the structure is the six-factor test from Whiteco Industries. The study applies both to your property and your invoices.
A study on a purchased building usually prices components from engineered estimates reconciled to the purchase price, because the original construction cost is unknown. A rehab changes that in your favor. You have a scope of work, contractor invoices, draw schedules, permits and photos, which is the documentation an engineer wants, and it supports Approach 1 pricing from actual cost records. Rehab spending is also richer in short-lived items than the shell: flooring, appliances, lighting, fencing, driveway, landscaping. The original structure is mostly framing, roof and foundation, which stay on 27.5 years. Renovation is one of the property types where the reclassified share can exceed the usual 20 to 35 percent of depreciable basis.
Before depreciation enters, you and your CPA decide which rehab dollars are repairs, deductible now, and which are improvements, capitalized and depreciated. The rules are the tangible property regulations, and the line is drawn in the repair-or-improvement rules. The concept that bites rehab investors is the betterment standard: spending that fixes a material condition or defect that existed when you bought the property is a capital improvement, even if the line items look like maintenance. The roof you replaced after closing and the panel you upgraded fixed conditions that came with the building. They are capitalized.
Three safe harbors help at the margins, each by election on a timely return. The de minimis safe harbor deducts items under $2,500 per invoice or item for a taxpayer without an audited financial statement. The small taxpayer safe harbor deducts repairs and improvements on a building with an unadjusted basis of $1,000,000 or less when the year's spending is under the lesser of $10,000 or 2 percent of that basis. The routine maintenance safe harbor covers recurring work expected more than once over the class life. None of them turns a gut renovation into a repair. Capitalize correctly, then accelerate through the study.
Depreciation starts when the property is ready and available for rent, whatever the closing date. The duplex was out of service while it was torn apart, so a February closing with a June finish means depreciation begins in June, and the bonus lands on the 2026 return. Finish in December and the deduction is this year; let it drag into January and it moves a return. Units placed in service one at a time each have their own date.
The One Big Beautiful Bill Act, Public Law 119-21, enacted July 4, 2025, restored 100 percent bonus permanently for qualifying property acquired and placed in service after January 19, 2025. Bonus reaches property with a recovery period of 20 years or less, which is exactly the 5-, 7- and 15-year property a study identifies, and not the 27.5-year structure. That is why the study is the gateway: without it, almost nothing in a residential rental is bonus-eligible. Improvements you pay to have installed are your own new property. The components inside a used building you buy qualify if you never used the property before and did not buy it from a related party. Bonus is automatic; the election is to opt out by class.
Illustrative, with land removed before anything is divided by 27.5. June mid-month on residential rental property is 1.970 percent in the first year.
| Line | No study | Engineered study |
|---|---|---|
| Purchase price | $400,000 | $400,000 |
| Land | $80,000 | $80,000 |
| Building | $320,000 | $320,000 |
| Capitalized rehab | $120,000 | $120,000 |
| Total depreciable cost | $440,000 | $440,000 |
| Reclassified to 5-, 7- and 15-year (25%) | $0 | $110,000 |
| Bonus depreciation, year 1 (100%) | $0 | $110,000 |
| Remaining on 27.5 years | $440,000 | $330,000 |
| 27.5-year depreciation, year 1 (1.970%) | $8,668 | $6,501 |
| Total first-year depreciation | $8,668 | $116,501 |
| Additional deduction | $107,833 | |
| Federal tax at 37% | $39,898 |
The $110,000 was the new flooring, appliances, lighting, window coverings, the fence, the driveway and the landscaping, from the rehab invoices, plus the components already in the building from the purchase. At 37 percent, the rate this site uses for comparability, the first year is worth $39,898; at Marlene's actual 32 percent bracket it is $34,507. The total depreciation over the life of the duplex is the same dollars either way. The study moves them forward, and time value is what you are buying: that $34,507 is most of the down payment on the next duplex.
A $116,501 first-year deduction on a duplex netting $18,000 before depreciation is a $98,501 paper loss. Rental activity is passive under Section 469, and passive losses offset only passive income. Three paths widen that.
The small-landlord allowance. Up to $25,000 of rental loss against other income for an owner who actively participates, phasing out between $100,000 and $150,000 of modified adjusted gross income. Marlene's salary puts her above it.
Real estate professional status. More than 750 hours and more than half of working time in real property businesses, with material participation in the rentals. Spouses cannot combine the hours, and Section 461(l) still applies above it.
The short-term rental route. Average stays of seven days or less take the property out of the rental definition, so an owner who materially participates treats the loss as nonpassive without professional status. The material participation tests are more than 500 hours, or more than 100 hours and not less than any other individual, and the hours have to be documented.
Marlene fits none of them this year. Her loss offsets the passive income from her three other rentals, and the rest carries forward on Form 8582, to be used against future passive income or released in full when she sells the duplex in a fully taxable sale. Above the passive rules sits Section 461(l), which caps net business losses against wages at $256,000 for a single filer and $512,000 on a joint return for tax years beginning in 2026, adjusted annually, with the excess carried forward as a net operating loss. Know your path before you order the study.
The R that scares people is the refinance. Loan proceeds are borrowed money, so a cash-out refinance creates no taxable income and leaves your depreciable basis alone; basis is built from what you paid and what you capitalized, and the new appraisal and the new loan never enter it. You can pull equity out and keep the full schedule. Financing also multiplies the benefit, because the deduction is computed on the whole basis while your cash in the deal is the down payment. The cautions: interest is deductible against the rental only to the extent the borrowed money is used for the rental under the tracing rules, so cash spent on personal items carries nondeductible interest, and the refinance date changes nothing about the placed-in-service date or the study.
Cost segregation applies only to depreciable property. Buy, renovate and sell as a business, and the house is inventory; the renovation is cost of goods sold when it sells, and nothing depreciates. The line is intent and facts: how long you held, whether you listed it for sale, how often you buy and sell, whether you actually rented it. An investor who buys to hold, rents, and later sells for a good reason looks different from one who resells renovated houses within months. If you do both, keep flips and rentals in separate entities with separate books. The rental side is where the study applies.
Depreciation on the 5- and 7-year property is recaptured as ordinary income under Section 1245 up to the depreciation taken. The 15-year land improvements are Section 1250 property: the bonus taken above straight-line is ordinary income under Section 1250, and the straight-line portion, like the building's depreciation, is unrecaptured Section 1250 gain at up to 25 percent. Basis is reduced by depreciation allowed or allowable, so skipping the study forfeits the benefit while the recapture stays. A 1031 exchange can defer the gain and the Section 1245 recapture, subject to the replacement property carrying enough Section 1245 property to absorb it, which is why BRRRR investors who keep trading up plan the exchange with the study in hand. And when you later replace a roof or an HVAC system, the partial asset disposition election, made as a rule on that year's timely filed return, writes off the remaining basis of the old one.
A look-back study analyzes the property as of its original in-service date, and the missed depreciation is claimed in the current year as a Section 481(a) adjustment through a change in accounting method on Form 3115, with no amended returns, at the bonus rate of the year the property went into service. Cost Seg America prepares the Section 481(a) computation and, for a separate fee, the Form 3115 itself; your CPA files it. For a current-year property, the real deadline is the filing date of the return, extensions included, rather than December 31.
A rehab study is only as good as its paper trail. For rehab investors the documents that matter most:
If your contractor billed "renovation, $120,000" on one line, ask for an itemized breakdown now, while the project is fresh.
The study is a tax position on your return. A fully engineered and accounted cost segregation study prices every component under the first two approaches the IRS Audit Techniques Guide describes, Approach 1 from your actual rehab invoices and Approach 2 from engineered estimates reconciled to the purchase price for the components that came with the building. On a duplex, the review is a live video walkthrough or a guided photo and video checklist you follow room by room, with the team reviewing every frame. The deliverable is a component schedule your CPA imports and an examiner can trace line by line, signed by credentialed professionals and engineered in the United States, and it is the document that makes a partial disposition possible when you replace the roof in year eight. An estimate applies a percentage and leaves you to defend it. Cost Seg America defends its studies for as long as you own the building, with no time limit, hour cap or additional fee, through written responses and participation in examiner calls alongside your CPA; our team has prepared and defended engineered studies since 2002. The fee is quoted in the proposal, before you commit to anything.
If the property has less than $180,000 of depreciable basis after land, counting the rehab, the fee can outweigh the benefit; a $150,000 house with a $30,000 rehab is usually too small. If you are going to flip it, there is nothing to study. If you plan to sell within a couple of years without exchanging, the ordinary-rate recapture on the reclassified property arrives before the time value has done anything. And if the loss would be passive, you have no passive income, and your exit is years away, the deduction is a carryforward with no date on it; it may be better to wait for a year in which one of the paths opens and bring the deduction forward then with a Form 3115.
Yes, when the property is held as a rental. The purchase price net of land and the capitalized rehab are both studied. A house renovated and sold as inventory is not depreciable.
The portion a study classifies as 5-, 7- or 15-year property is, at 100 percent, for property acquired and placed in service after January 19, 2025. Costs that are part of the 27.5-year structure are not.
No. Depreciation runs on cost basis, and the appraisal and loan size never touch it. The proceeds are borrowed money, and the tracing rules decide how much of the new interest is deductible.
Not necessarily. Professional status, a short-term rental you materially participate in, or the small-landlord allowance each works. Otherwise the loss offsets passive income and carries forward.
No, while you still own the property. A look-back study with Form 3115 claims the missed depreciation in the current year without amending prior returns.
Basis includes the materials you bought and the subcontractors you paid, and the study addresses those; your own labor stays out of it. Keep the receipts.
The floor is $180,000 of depreciable basis after land, including the rehab. The free proposal will say if the property falls short.
Depreciation on the 5- and 7-year property is recaptured as ordinary income under Section 1245, bonus above straight-line on the 15-year land improvements is ordinary under Section 1250, and the rest is unrecaptured 1250 gain at up to 25 percent. A short hold is the main reason to skip a study; a 1031 exchange can change the answer. Marlene plans to hold her duplex for at least a decade, which is what makes the study worth ordering.
Marlene's $120,000 of rehab invoices turned an $8,668 first-year deduction into $116,501. If you have a rehab underway, just finished one, or closed on a renovated property in a prior year, send the address, the purchase price, the rehab budget and the date the units were ready to rent. Jim Dougherty and his team will send a free proposal within 24 hours showing the projected first-year deduction, and will say plainly if a study is not right for the property. Bring your CPA into the conversation. Call 1-888-365-5023 or email info@costsegamerica.com.
This article is for educational purposes only, with illustrative rounded figures, and is not tax, legal or accounting advice; confirm your situation with your CPA before acting.
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