Business remodeling expenses are tax deductible, but the IRS decides how fast you get the money back. Straightforward repairs come off your taxes in full the year you pay for them. Capital improvements have to be added to the property’s basis and recovered through depreciation. The good news for 2026: with 100 percent bonus depreciation permanently restored for qualifying property acquired after January 19, 2025, most interior improvements to a commercial building can be written off entirely in the year they’re placed in service.
Repair or Capital Improvement
Everything starts with this classification. Ordinary repairs and maintenance are deductible in the year you pay for them as ordinary and necessary business expenses.1Internal Revenue Service. Tangible Property Final Regulations Capital improvements have to be capitalized and depreciated.2Office of the Law Revision Counsel. 26 US Code 263 – Capital Expenditures
The IRS applies three tests. If any one applies, you’re looking at an improvement.3eCFR. 26 CFR 1.263(a)-3 – Amounts Paid to Improve Tangible Property
- Betterment. The work fixes a pre-existing defect, physically enlarges the property, or materially increases productivity, efficiency, or quality. Knocking out a wall to add 500 square feet of retail space is a betterment. Patching drywall is not.
- Adaptation. The project converts the space to a new or different use inconsistent with the original use. Turning a storage room into a commercial kitchen qualifies; repainting it doesn’t.
- Restoration. You’re replacing a major structural component or rebuilding after significant damage or wear. A full roof replacement is a restoration. Sealing a few leaks is a repair.
Borderline calls are common, and the safe harbors below let you skip the judgment for smaller or recurring items.
The Two Safe Harbors That Cover Small Expenses
De Minimis Safe Harbor
Without audited financial statements, you can deduct any individual item or invoice of $2,500 or less in the year you pay for it, no repair-versus-improvement analysis required.1Internal Revenue Service. Tangible Property Final Regulations With audited statements, the threshold rises to $5,000 per item or invoice.4Internal Revenue Service. Notice 2015-82 – Increase in De Minimis Safe Harbor Limit The election is made annually on your return, and it applies per invoice or per item as shown on the invoice.
A practical point that gets missed: how the contractor bills you matters. An $8,000 lump-sum invoice for light fixtures, outlet covers, and door hardware doesn’t qualify. The same work billed with each item under $2,500 does. Ask for itemization before the invoice arrives.
Routine Maintenance Safe Harbor
Recurring upkeep that you reasonably expect to perform more than once during the first ten years after a building is placed in service qualifies here.1Internal Revenue Service. Tangible Property Final Regulations The activity must keep the building in ordinarily efficient operating condition rather than upgrade it. HVAC filter changes, annual parking-lot sealcoating, and periodic repainting of interior walls fit. A one-time gut renovation does not, no matter what the invoice calls it.
Writing Off an Improvement in Year One
Once a project counts as a capital improvement, two provisions can still let you deduct the full cost immediately.
Bonus Depreciation and Qualified Improvement Property
Qualified improvement property covers any improvement to the interior of an existing nonresidential building, with three exclusions: enlarging the building, elevators or escalators, and modifications to the internal structural framework.5Legal Information Institute. 26 USC 168(e)(6) – Qualified Improvement Property It carries a 15-year recovery period, which sits under the 20-year bonus-depreciation threshold.
The One, Big, Beautiful Bill permanently restored 100 percent first-year bonus depreciation for qualified property acquired after January 19, 2025.6Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill Remodel the interior of your commercial space in 2026 and you can write the whole cost off in year one. That’s a real reversal from the phasedown period (60 percent in 2024, 40 percent for early 2025). If you deferred work while the benefit was shrinking, the math has flipped.
A handful of states, including California, New York, and New Jersey, don’t conform to federal bonus depreciation. You take the full federal deduction but may need to add all or part of it back on your state return.
Section 179 Expensing
Section 179 lets you deduct the full cost of qualifying property in the year you place it in service, up to an annual cap. For tax years beginning in 2026, the base deduction limit is $2,500,000, with a dollar-for-dollar phase-out starting once total qualifying purchases exceed $4,000,000 (both inflation-adjusted).7Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets Those numbers cover the entire cost of most small and mid-size projects.
Section 179 specifically covers these categories of nonresidential real property improvements placed in service after the building itself was first placed in service:
- Roofing
- Heating, ventilation, and air conditioning systems
- Fire protection and alarm systems
- Security systems
- Qualified improvement property (most other interior improvements)
Section 179’s advantage over bonus depreciation is flexibility. You pick exactly how much to expense in a given year, which helps when you’re managing taxable income. Its downsides are the annual cap and the phase-out, which really only bite on very large projects or years with heavy asset buying.
Cost Segregation for Larger Projects
A commercial building’s cost basis depreciates over 39 years by default. A cost segregation study breaks the building into components and reclassifies items like specialized electrical work, decorative finishes, cabinetry, and site improvements into 5-year, 7-year, or 15-year categories. Every dollar shifted into a shorter-life bucket becomes bonus-eligible and can be written off in year one.
Studies typically move 20 to 40 percent of a building’s total cost into bonus-eligible categories. On a $1 million remodel, that’s $200,000 to $400,000 in first-year deductions instead of decades of drip-feed depreciation. The study itself runs a few thousand dollars for a moderately sized project, and the payoff generally dwarfs the fee.
Cost segregation pairs well with a partial asset disposition election. When your remodel rips out old roofing, HVAC, interior partitions, or flooring, you can deduct the remaining undepreciated basis of those retired components in the year you remove them.8eCFR. 26 CFR 1.168(i)-8 – Dispositions of MACRS Property Without a study, there’s usually no credible way to assign a cost to the old component, and the deduction goes unclaimed. The election has to be made on a timely filed return for the year of the disposition.
Accessibility Incentives That Stack
Remodeling to improve accessibility can unlock two federal incentives that work together on the same project.
The disabled access credit gives eligible small businesses a credit equal to 50 percent of accessibility-related expenses over $250 and up to $10,250, for a maximum annual credit of $5,000.9Office of the Law Revision Counsel. 26 US Code 44 – Expenditures to Provide Access to Disabled Individuals Eligibility requires either gross receipts of $1 million or less, or no more than 30 full-time employees, in the prior tax year. Qualifying expenses include removing physical barriers, modifying equipment, and providing accessible communication.
The architectural barrier removal deduction lets businesses of any size deduct up to $15,000 a year for expenses related to removing barriers for people with disabilities.10Office of the Law Revision Counsel. 26 US Code 190 – Expenditures to Remove Architectural and Transportation Barriers Both incentives can apply to the same year’s project, but the deduction is reduced by the amount of the credit claimed.11Internal Revenue Service. Tax Benefits for Businesses That Accommodate People With Disabilities
One boundary worth noting for energy-efficiency work: the Section 179D deduction for energy-efficient lighting, HVAC, or building envelope components will not apply to property whose construction begins after June 30, 2026.12US Department of Energy. 179D Energy Efficient Commercial Buildings Tax Deduction If energy upgrades are part of the plan, construction has to start before that date to qualify.
If You Lease Instead of Own
When the space is leased, deductions follow whoever pays for and owns the improvements.13Office of the Law Revision Counsel. 26 US Code 168 – Accelerated Cost Recovery System A tenant who pays for improvements, receives no reimbursement, and hasn’t structured the arrangement as a substitute for rent depreciates the assets. Recovery period tracks the property classification (15 years for qualified improvement property), not the lease term. A landlord’s cash allowance for tenant improvements is generally taxable income to the tenant, and the tenant then claims the depreciation.
There’s an exception for short-term retail leases of 15 years or less: if the tenant gets an allowance to build improvements that revert to the landlord at lease end, the payment can be excluded from the tenant’s income. Whichever arrangement applies, spell out ownership of the improvements in the lease so the tax treatment isn’t ambiguous later.
Documentation and Forms
Recordkeeping starts on day one of the project. Get itemized invoices that split labor from materials, keep a log of start and finish dates (the “placed in service” date triggers depreciation), and retain contracts, permits, and change orders.
Depreciation deductions are reported on IRS Form 4562, attached to the business return.14Internal Revenue Service. Form 4562 – Depreciation and Amortization Part III captures the classification, cost basis, and recovery period for property placed in service during the year.15Internal Revenue Service. Instructions for Form 4562 Sole proprietors attach it to Schedule C, C-corporations file it with Form 1120, and partnerships and S-corporations use their respective entity returns.
Cost basis generally includes everything paid to acquire and install the improvement: purchase price, freight, and installation labor.16Internal Revenue Service. Topic No. 703, Basis of Assets If the property isn’t used entirely for business, reduce the depreciable basis by the personal-use percentage.
Keep records for the full depreciation life of the asset plus three additional years, since the IRS can examine any return in which a depreciation deduction was claimed.17Internal Revenue Service. How Long Should I Keep Records Losing documentation partway through can expose you to a 20 percent accuracy-related penalty on the underpayment.18Office of the Law Revision Counsel. 26 US Code 6662 – Imposition of Accuracy-Related Penalty on Underpayments Digital backups stored separately are the simplest protection over a 15- or 39-year depreciation cycle.
Fixing a Missed Deduction From a Prior Year
If you capitalized an expense that should have been deducted, or you forgot to claim depreciation at all, file IRS Form 3115 to change your accounting method.19Internal Revenue Service. Instructions for Form 3115 This isn’t an amended return. It’s a method change that catches up all prior-year missed deductions in a single Section 481(a) adjustment on the current year’s return.
Many depreciation-related corrections qualify for the automatic change procedure: no user fee, no waiting for IRS approval. File the form with the current-year return and attach a statement showing the catch-up calculation. A negative adjustment (benefit to you) is taken entirely in the year of change; a positive adjustment is spread over four years. A remodel that has been depreciating over 39 years but actually qualified as 15-year qualified improvement property eligible for bonus depreciation can produce a substantial cumulative deduction through this route.