No, a roof replacement does not qualify for bonus depreciation when the roof is installed on a commercial building. Bonus depreciation is limited to property with a MACRS recovery period of 20 years or less, and a roof is treated as part of the 39-year building structure. The useful workaround is Section 179, which specifically lists roofs on nonresidential buildings as eligible for full first-year expensing. For most commercial roof projects in 2026, the practical result is the same deduction you were hoping bonus depreciation would deliver.
Why the Roof Doesn’t Qualify
Bonus depreciation under IRC Section 168(k) applies only to tangible property with a MACRS recovery period of 20 years or less.1Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill A commercial building is nonresidential real property with a 39-year recovery period, and the roof is treated as part of that structure.2Internal Revenue Service. Publication 946, How To Depreciate Property That alone disqualifies it.
The one classification that could have shortened the roof’s life is Qualified Improvement Property, which carries a 15-year recovery period and is fully bonus-eligible. QIP doesn’t reach a roof. IRS Publication 946 defines QIP as an improvement to the interior portion of a nonresidential building placed in service after the building was first placed in service, and excludes enlargements, elevators, escalators, and changes to internal structural framework.2Internal Revenue Service. Publication 946, How To Depreciate Property A roof is an exterior component. Publication 946 also lists roofs separately as qualified Section 179 real property, which only makes sense because they are not QIP.
Section 179 Is the Actual Path to Full Expensing
IRC Section 179(e) treats a roof replacement on a nonresidential building as “qualified real property” that can be fully expensed in the year it is placed in service, as long as the improvement is made after the building was originally placed in service.2Internal Revenue Service. Publication 946, How To Depreciate Property The statute names four categories of nonresidential improvements that qualify for Section 179 even though they fall outside QIP:
- Roofs
- Heating, ventilation, and air-conditioning property
- Fire protection and alarm systems
- Security systems
For tax year 2026, the maximum Section 179 deduction is approximately $2,560,000, with the phase-out beginning once total qualifying property placed in service during the year exceeds approximately $4,090,000. These limits adjust for inflation. Most roof replacements sit well below the cap, so the whole cost can be expensed in year one.
Section 179 carries one restriction that bonus depreciation does not. The deduction cannot exceed the taxpayer’s net taxable business income for the year. If your business shows $200,000 of taxable income and you spend $350,000 on a new roof, Section 179 covers $200,000 and the remaining $150,000 carries forward. Bonus depreciation, by contrast, can create or deepen a net operating loss. For a large roof on a thin-income year, that income cap is the main thing to plan around.
Is the Work Even a Capital Improvement?
None of this matters if the work is actually a repair, because repairs are deducted immediately with no Section 179 or bonus depreciation needed. Under the tangible property regulations, a capital improvement is an expenditure that produces a betterment, adaptation, or restoration of the property.3Internal Revenue Service. Tangible Property Final Regulations A full roof replacement almost always counts as a restoration because the roof is a major component of the building. Replacing load-bearing structural elements that support more than 40 percent of the roof, or replacing more than 40 percent of the insulation layer, pushes the entire cost into capital territory. Patching a leak or swapping out a section of flashing usually stays a deductible repair.
Residential Rental Property Is a Different Rule
Everything above is written for nonresidential buildings. If you own residential rental property, the rules are harder. A roof on residential rental is depreciated over 27.5 years as part of the building, which exceeds the 20-year bonus depreciation threshold.2Internal Revenue Service. Publication 946, How To Depreciate Property The Section 179 categories for roofs, HVAC, fire protection, and security systems apply only to nonresidential real property, so a landlord replacing the roof on an apartment building has to capitalize the cost and depreciate it over 27.5 years using the straight-line method. The only opening is a cost segregation study that identifies specific components as shorter-lived personal property.
Components That Can Still Get Bonus Depreciation
Even though the roof itself is 39-year property (or Section 179 qualified real property), a roofing project often bundles in components with shorter recovery periods that genuinely do qualify for bonus depreciation. Electrical conduit, drainage systems, specialized ventilation equipment, and certain mechanical components installed as part of the project may fall into 5-year, 7-year, or 15-year classes depending on their function.
A cost segregation study breaks the total project cost into components and assigns each to the correct asset class. With 100 percent bonus depreciation restored permanently for qualified property acquired after January 19, 2025,1Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill reclassified components are fully deductible in year one. The study should be done by a qualified engineering firm, with documentation to back each reclassification. The IRS has issued audit technique guides for cost segregation, and positions without engineering support tend to draw scrutiny.
Watch the Section 163(j) Election
If your business has elected to be treated as an electing real property trade or business under IRC Section 163(j)(7)(B) to avoid the business interest expense limitation, there is a catch on the depreciation side. The electing business must depreciate nonresidential real property, residential rental property, and QIP using the Alternative Depreciation System.4Internal Revenue Service. Questions and Answers About the Limitation on the Deduction for Business Interest Expense Property depreciated under ADS cannot take bonus depreciation, so even interior QIP you might otherwise bonus becomes ineligible once the election is in place. Section 179 remains available, which means a roof replacement can still be fully expensed under Section 179 after the election.
Claiming It on Form 4562
Both Section 179 and bonus depreciation are claimed on Form 4562 for the year the roof is placed in service.5Internal Revenue Service. About Form 4562, Depreciation and Amortization The Section 179 election for the roof goes in Part I, and the elected amount reduces the asset’s depreciable basis. Any cost-segregated components that qualify for bonus depreciation go in Part II under the Special Depreciation Allowance. Any remaining basis after Section 179 and bonus moves to Part III for regular MACRS depreciation over 39 years.6Internal Revenue Service. Instructions for Form 4562
The total from Form 4562 flows to the appropriate line of your business return: Schedule C for sole proprietors, Form 1065 for partnerships, Form 1120-S for S corporations, or Form 1120 for C corporations. Keep contractor invoices that separate labor, materials, and component costs. That paper trail makes the Section 179 election and any cost segregation reclassifications much easier to defend on examination.
State Taxes May Not Follow
Federal and state depreciation rules often diverge. Many states have decoupled from federal bonus depreciation to protect their revenue bases, and the permanent restoration of 100 percent bonus depreciation under the OBBBA may prompt more to decouple. A business that expenses the full roof cost federally may have to add back part of the deduction on the state return and depreciate the roof over the standard recovery period for state purposes. Check your state’s conformity rules before assuming the federal treatment carries over.