Partial Asset Dispositions: The Write-Off Hiding in Every Renovation

When you replace a building component, the old one does not leave your depreciation schedule on its own. Its remaining cost usually stays inside the building asset and keeps depreciating for another 20 or 30 years, which is why it gets called a phantom roof. A partial disposition election under Treas. Reg. §1.168(i)-8 can let your preparer recognize that remaining basis in the year the component came out. It is available only if the component was placed in service by you, is not in a general asset account, was yours rather than a tenant’s, and the filing deadline for the year of removal has not passed.

What a partial disposition is

A building is one depreciable asset. Its structural components, the roof, HVAC, windows, walls, plumbing and electrical distribution, are part of that asset rather than assets of their own. So when you tear off a roof after nine years and put on a new one, the new roof starts its own depreciation schedule, and the old roof’s undepreciated cost keeps depreciating inside the building as if it were still there.

The partial disposition rule lets you treat the removed portion as disposed of. Its adjusted basis comes off the building, and the gain or loss on it is recognized in the year of removal. For structural components that treatment is elective, and the election is the part people miss.

It matters most on the projects we already see in renovation studies: roof replacements, HVAC change-outs, storefront and facade work, interior demolition for a new tenant, and kitchen and bath gut-renovations on rentals.

The election, and why the deadline is the whole game

The election is made by reporting the disposition on a timely filed original return, including extensions, for the year of disposition. No separate statement is required. A superseding return, one filed before the extended deadline to replace a return already filed, is still an original return, so a filed return does not by itself close the door while the window is open.

After the deadline, the options narrow sharply:

• The late-election method change is closed. A one-time automatic change (DCN 196) once let taxpayers make late partial disposition elections through Form 3115. It is no longer available for current years; it closed after tax years beginning in 2014.
• DCN 198 is for exams, not second thoughts. The current automatic-change list, Rev. Proc. 2025-23 §6.10, keeps a partial disposition change that applies when the IRS disallows a repair deduction on examination and capitalizes the cost. It is not a general route for an election you did not make.
• Otherwise it is discretionary relief under §301.9100-3, which is a request, not a filing.

So the practical question is not “can we do this someday” but “is the return for the year of removal still open.” For an individual on extension for 2025, the extended deadline is October 15, 2026. Your preparer confirms the date that applies to you.

The gate that surprises buyers

The first gate is the one that catches people after a value-add purchase. Only property you placed in service can be disposed of. If you bought a building and gutted it before it was ever ready and available for rent or used in your business, the interior you demolished never became a depreciable asset in your hands, so there is nothing to dispose of. What you paid for it is a basis question for the rehab, not a disposition. You would still have an acquisition study and a renovation study; you would not have a partial disposition.

If the building was in service before the demolition, even briefly, the analysis changes, and how long it was in service is a question for your preparer.

Separately depreciated items versus structural components

Not every removal needs the election. If a prior cost segregation study already split an item out as its own 5-, 7- or 15-year asset (carpet, cabinetry, dedicated equipment circuits, site paving), that item is its own asset. Retiring it is a disposition of that asset, and no election is required.

Structural components are different. A roof, an HVAC system or a set of interior walls stays inside the building asset even after a study, so recognizing its removal does require the election. A useful disposition schedule keeps the two apart: “disposition of a separately depreciated asset” on one side, “partial disposition of the building, election required” on the other.

How the removed basis is measured

The number that matters is the adjusted basis of the removed portion: its original cost, minus the depreciation allowed or allowable on it through the disposal date, including any bonus depreciation or §179 attributable to it.

When original cost cannot practicably be determined from your records, the regulation allows any reasonable method, applied consistently to the asset. Three are commonly used:

• Discounting the replacement cost with the Producer Price Index back to the year the building was placed in service. This is only for a restoration, not a betterment or an adaptation, and only where the result is reasonable. The IRS’s own examiner guidance gives a discounted roof cost larger than the building’s basis as an example of an unreasonable result.
• Pro rata by replacement cost: the unadjusted basis of the asset, times the replacement cost of the removed portion divided by the replacement cost of the whole asset. For a structural component, the asset is the building.
• A cost segregation study that already allocates cost to the component. If we studied your acquisition, the removed roof or finishes already have an original cost and a placed-in-service date on the schedule.

Accumulated depreciation should come from what was actually claimed: your fixed-asset ledger, prior Forms 4562, or a figure from your preparer. It should not be modeled from statutory rates alone, because bonus depreciation, §179 and method changes all change it.

Amount realized, removal costs, and Form 4797

The loss is not simply the adjusted basis. Recognized gain or loss equals the amount realized minus the adjusted basis of the removed portion. Scrap value, salvage proceeds and insurance recoveries are all amounts realized, and each one shrinks the loss. Most removals realize nothing, but the question should be asked.

Removal costs are a separate line. Demolition and haul-off are shown on their own. When the adjusted basis of a removed component is taken into account as a loss, the replacement is treated as a restoration and capitalized under §1.263(a)-3(k), and the removal costs are then not required to be capitalized under §1.263(a)-3(g)(2). Whether they are deducted or capitalized is your preparer’s decision.

The disposition goes on Form 4797. Character (§1231, §1245 or §1250), netting, the §1231 lookback and passive-loss limits are all the preparer’s determination, and they affect what the election is worth to you. The building’s basis drops by the disposed portion.

An illustrative example

The figures below are illustrative, built to show the arithmetic. They are not a client engagement.

An owner buys a small office building and places it in service in January 2016. A cost segregation study on the purchase allocates $120,000 of the building’s cost to the roof. In June 2025 the roof is torn off and replaced.

In this example the owner’s ledger shows straight-line depreciation on the building with no method changes, so the roof’s share follows the same schedule. A real ledger may differ, and the real figure governs.

Without the election, that $91,026 would keep depreciating at about $3,077 a year for close to 30 more years while the roof it represents sits in a landfill. With the election on a timely 2025 return, it is recognized in 2025. At a 37% federal rate a loss of that size could be worth roughly $33,700, but the actual effect depends on character, netting and passive-loss rules, so treat that as an order of magnitude rather than a result. Removal costs for the old roof would be listed separately for the preparer.

What we do, and what your preparer does

We compute and document; your preparer makes the election. Our partial asset disposition study produces a disposed-asset schedule with one row per removed item: the original placed-in-service date, original cost and the method used (with the reason), accumulated depreciation and its source, adjusted basis, amount realized, recognized gain or loss, removal costs, and whether the election is required. It comes with a methodology narrative, a section for the preparer on the election mechanics and Form 4797, and import rows for their software.

Your preparer decides whether to elect, decides repair versus capitalization, characterizes the result, and files. We do not promise a fix for a year whose filing window has closed.

The price is one flat fee: $995 per building, the same whether it is added to a renovation study or bought on its own. The intake answers decide whether the study can be done, never what it costs, so a roof with a clean ledger and a gut renovation with a rebuilt depreciation history are the same price.

Each additional building is its own engagement at the same fee. Details are on our pricing page. It is quoted on the renovation-study intake or by proposal; email hello@costsegsmart.com with what was removed, when, and the property’s placed-in-service date, and our team will tell you whether the four gates hold before anything is priced.

If you would rather send it in one file, our partial disposition questionnaire (Excel) asks for the same facts, plus removal costs, rents and the renovation.

For how the renovation spend itself is classified, see cost segregation for renovations. For the landlord side of a tenant’s demolished fit-out, see who depreciates a build-out.