Section 179 Leasehold Improvements: Stop Waiting to Deduct Buildout Costs

Section 179 leasehold improvements let you write off the full cost of your commercial space improvements in year one instead of waiting 39 years. This powerful tax break applies to interior modifications to nonresidential property and can put thousands back in your business account immediately, transforming how you handle buildout expenses.

Key Takeaways

• You can deduct up to $1.29 million in qualifying improvements immediately instead of depreciating them over decades
• Both tenants and property owners can claim these deductions if they pay for the improvements
• Interior upgrades like HVAC systems, lighting, and security systems qualify, but structural changes don’t
• Phase-out begins at $3.22 million in total property purchases per year
• Cost segregation studies help identify which components qualify for maximum savings

What Makes Section 179 Leasehold Improvements Different from Regular Depreciation

Here’s the thing most business owners don’t get about property improvements. Under normal rules, you’d depreciate that $150,000 restaurant buildout over 39 years. That’s roughly $3,850 per year. But with Section 179 leasehold improvements, you could write off the entire amount in year one.

The difference hits your cash flow like a freight train. One of my clients, a dental practice owner in Phoenix, spent $200,000 renovating a leased space. She nearly fell out of her chair when I showed her she could deduct it all immediately rather than taking $5,128 annually for four decades.

The Tax Cuts and Jobs Act changed everything in 2017. What used to be called “qualified leasehold improvement property” got rolled into something broader: qualified improvement property. The government realized businesses needed faster tax relief on property improvements to stay competitive.

Who Actually Gets the Deduction

Pay attention here because this trips up a lot of people. Whoever pays for the improvements claims the deduction. If you’re a tenant and you funded that new floor-to-ceiling renovation, the deduction is yours. Not your landlord’s.

But read your lease. Some agreements specify that permanent improvements immediately become landlord property. A salon owner in Portland learned this the hard way after spending $85,000 on built-in stations and plumbing upgrades. Her lease said anything “permanently affixed” transferred to the landlord. She could only claim about 30% of her costs under Section 179 after we separated trade fixtures from permanent improvements.

The Real Numbers for 2025

For 2025, you can expense up to $1.29 million under Section 179. The phase-out starts when your total qualifying property purchases hit $3.22 million for the year. After that threshold, your deduction drops dollar-for-dollar. Spend more than $4.51 million total, and Section 179 disappears completely.

These limits apply to everything you buy that qualifies for Section 179, not just leasehold improvements. If you bought $800,000 in equipment and spent $600,000 on buildout improvements, you’re at $1.4 million total—well within the limit.

Quick Reference: Does Your Improvement Qualify?

Improvement Type	Section 179 Eligible?	Key Requirement
New HVAC System	Yes	Must be for nonresidential property
Interior Lighting Upgrade	Yes	Placed after building was first used
Security System Installation	Yes	Must serve business purpose
New Elevator	No	Specifically excluded by IRS
Load-Bearing Walls	No	Internal structural framework excluded
Building Addition	No	Enlargements don’t qualify
Fire Protection System	Yes	Interior components qualify
Roof Replacement	Yes	Added after building was in service

Understanding Qualified Improvement Property (The IRS’s New Name)

After 2017, the IRS consolidated several categories into one: qualified improvement property. This matters because QIP defines what qualifies for both Section 179 and bonus depreciation.

QIP means any improvement you make to the interior of a nonresidential building after it was first put into service. Restaurants, offices, retail spaces, warehouses—all qualify. Apartments, condos, nursing homes? Those don’t.

The exclusions matter more than the inclusions. You cannot claim Section 179 for:

Enlargements. Add a new wing to your building? That extra square footage doesn’t qualify. Only improvements within the original footprint count.

Elevators and escalators. These are specifically called out in the tax code as ineligible, regardless of when you install them.

Internal structural framework. This is where it gets tricky. Load-bearing walls, columns, girders, trusses—anything essential to keeping the building standing—is excluded. The IRS considers these “structural” rather than “improvements.”

The Gray Areas That Confuse Everyone

HVAC systems drive people crazy with confusion. Here’s the reality: interior components like ductwork, thermostats, and control systems typically qualify as QIP. But rooftop units, external condensers, and chillers sitting outside the building envelope? Those generally don’t qualify because they’re exterior components.

A restaurant chain we worked with spent $320,000 on HVAC renovations across three locations. Through proper cost segregation, we identified $210,000 in interior ductwork and controls that qualified for Section 179, while $110,000 in rooftop units went into a different category.

Mixed-use buildings create another headache. If more than 80% of your building’s income comes from residential sources, the IRS treats it as residential property. Your improvements won’t qualify for Section 179, even if you’re renovating the commercial portion.

How Section 179 Works with Your Active Business

Section 179 has one limitation that catches people off guard: it cannot create a business loss. You can only deduct up to your taxable business income for the year.

Let’s say your business had $80,000 in taxable income for 2025, and you completed $150,000 in qualifying improvements. You can deduct $80,000 this year under Section 179. The remaining $70,000 carries forward to next year. It doesn’t disappear.

This differs from bonus depreciation, which can create losses that carry forward as net operating losses. Choosing between the two strategies depends on your specific tax situation.

The Active Business Requirement

Your property expensing through Section 179 only works if you use the property in an “active trade or business.” Passive rental properties don’t qualify, with limited exceptions for certain real property improvements.

A real estate investor who owns ten rental properties learned this distinction. He couldn’t use Section 179 for general rental property improvements. But when he operated a property management company from one of the buildings, improvements to that office space qualified because it supported his active business operations.

Critical Details Most Businesses Overlook

• Timing matters: The property must be placed in service during your tax year. Just signing a contract isn’t enough—the improvements must be complete and ready for use.
• You must make the improvements: If you buy a building where the previous owner made improvements, you can’t treat those costs as QIP. Only improvements you make or pay for qualify.
• Step-in-the-shoes transactions have special rules: Contributing property to a partnership in a tax-free exchange? The partnership steps into your shoes for remaining depreciation, but new improvements don’t get bonus treatment.
• Documentation requirements are strict: You’ll file Form 4562 with your tax return, listing each improvement and the amount you’re expensing. Generic descriptions won’t survive an audit.
• Recapture rules apply on sale: If you sell the property within five years, you may need to recapture some of the Section 179 deduction as ordinary income.

State Tax Complications Nobody Warns You About

Here’s where federal tax breaks can turn into state tax headaches. Many states don’t fully conform to federal Section 179 rules.

California, for example, caps Section 179 deductions at $25,000 with a phase-out starting at $200,000. You could claim $1 million federally but only $25,000 on your California return. The difference? You depreciate it over the normal period for state purposes while expensing it immediately for federal.

Pennsylvania limits Section 179 to your active business income reported to Pennsylvania. New York has its own Section 179 limits that don’t match federal numbers. Massachusetts requires add-backs for certain bonus depreciation amounts.

This creates planning opportunities. If you operate in multiple states with different conformity rules, timing your improvements strategically can minimize total tax liability across all jurisdictions.

Local Taxes Add Another Layer

Some cities impose their own taxes on business income. New York City, San Francisco, and Portland have local business taxes with their own depreciation rules. A Portland food cart commissary owner discovered his $95,000 facility upgrade qualified differently for federal, Oregon state, and Portland city taxes, requiring three separate depreciation schedules.

Section 179 vs. Bonus Depreciation: Comparison

Feature	Section 179	Bonus Depreciation
Annual Limit	$1.29M (2025)	No limit
Can Create Loss?	No—limited to business income	Yes—creates NOL carryforward
Election Method	Opt-in (you choose which assets)	Automatic (must opt out)
State Conformity	More states conform	Many states don’t allow
Phase-Out Threshold	$3.22M in total purchases	None
Current Rate (2025)	100% of qualifying property	40% (if acquired before 1/19/25)
Planning Flexibility	High—choose specific assets	Low—all or nothing

Why Cost Segregation Makes or Breaks Your Savings

Most businesses treat their entire buildout as one lump sum. That’s leaving money on the table.

Cost segregation breaks down your improvements into components with different tax lives. Your $400,000 restaurant renovation isn’t just one 15-year asset. It might include:

• $80,000 in removable equipment (5-year property)
• $120,000 in lighting and electrical (7-year property)
• $150,000 in interior finishes (15-year QIP)
• $50,000 in land improvements like parking lot repairs (15-year property)

Each category gets different tax treatment. The 5-year and 7-year property might qualify for higher bonus percentages. The QIP qualifies for Section 179. Land improvements get their own depreciation schedule.

A cost segregation study from a qualified firm identifies these components. The study provides documentation that holds up under IRS scrutiny, showing why each component fits its assigned category.

Real-World Impact

A medical practice in Austin spent $550,000 renovating their leased space. Without cost segregation, they’d depreciate everything as 15-year QIP. With proper analysis, they reclassified:

$160,000 in medical equipment and specialty lighting to 5-year property. $90,000 in exam room fixtures and decorative elements to 7-year property. $300,000 in qualifying interior improvements to 15-year property eligible for Section 179.

The practice used Section 179 to expense the full $300,000 in QIP immediately. They applied bonus depreciation to the 5-year and 7-year property. First-year deductions jumped from approximately $37,000 to $462,000, creating a massive cash flow benefit.

Common Mistakes That Cost Real Money

Claiming improvements you didn’t pay for. Your landlord upgraded the building’s facade before you moved in. You can’t claim those costs just because you’re leasing the space. Only improvements you fund qualify.

Ignoring the placed-in-service date. You signed the contract in December 2024 but the work finished in January 2025. The deduction goes on your 2025 return, not 2024.

Mixing personal and business use. Built a combination office-apartment space? Only the business portion qualifies. The IRS requires clear documentation separating business from personal square footage and costs.

Failing to properly elect Section 179. The deduction isn’t automatic. You must complete Part I of Form 4562 and file it with your return. Miss this step, and you’ve missed your window.

Not tracking carryforwards. If your business income limits your Section 179 deduction this year, that unused amount carries forward. But you need records showing the carryforward amount, or you’ll lose track of money you’re entitled to deduct later.

Working with Professional Cost Segregation Firms

Look, you can try to categorize these improvements yourself. But the IRS isn’t accepting guesswork on six-figure deductions.

A qualified cost segregation firm employs engineers who physically inspect your property. They review construction documents, analyze building systems, and create defensible reports that classify each component correctly. This isn’t something your regular CPA does—it requires specialized engineering and tax expertise.

The firm’s report becomes your audit protection. When the IRS questions why you claimed that $200,000 deduction, you hand them a 100-page engineered study with photos, calculations, and tax code citations.

Brian Hagene, CPA and partner at Mathieson, Moyski, Austin & Co., notes that “practitioners will need to analyze and compare the tax savings between bonus depreciation vs. Sec. 179 expensing deductions to determine the best outcome for taxpayers.

The cost? Typically $5,000 to $15,000 for most commercial properties, depending on complexity. But the tax savings usually run 10 to 50 times the study cost. That medical practice I mentioned earlier paid $8,500 for their cost segregation study and generated $425,000 in first-year deductions they wouldn’t have claimed otherwise. At a 35% combined tax rate, that’s $148,750 in tax savings on an $8,500 investment.

Choosing the Right Firm

Not all cost segregation firms are equal. Look for these qualifications:

• Licensed engineers on staff who conduct actual site visits
• Detailed reports that comply with IRS Audit Technique Guide requirements
• Experience in your specific property type (retail, medical, industrial, etc.)
• References from CPAs who’ve had their studies survive IRS audits
• Clear explanations of methodology and findings

Avoid online calculators or “desktop studies” that don’t involve physical property inspection. The IRS views lack of site inspection as a red flag. When significant money is at stake, cutting corners on the study costs you far more in lost deductions and potential penalties.

Federal, State, and Local Law Impact Summary

Federal law through the Tax Cuts and Jobs Act sets the baseline for Section 179 treatment of leasehold improvements. The Internal Revenue Service defines eligibility, limits, and phase-out thresholds that apply nationwide. Revenue procedures and IRS guidelines provide detailed implementation rules.

State conformity varies dramatically. Some states fully adopt federal Section 179 rules with identical limits. Others impose their own caps, phase-outs, or add-back requirements that create state-federal differences. These variations mean a federal deduction doesn’t automatically translate to state tax savings.

Local jurisdictions with income-based business taxes may have separate rules. Cities like New York, San Francisco, and Philadelphia impose local business taxes with varying treatment of depreciation and expensing. Property tax assessments may also change when you make substantial improvements, affecting your ongoing property tax burden beyond income tax considerations.

The interplay between federal, state, and local rules requires coordination with tax professionals who understand multi-jurisdictional compliance. What works perfectly for federal taxes might create unfavorable state consequences without proper planning.

Making Your Decision

Section 179 for leasehold improvements isn’t an all-or-nothing choice. You select which improvements to expense, how much to deduct, and when to claim it.

Your decision should consider: Current-year income levels, multi-year tax projections, state conformity in your jurisdiction, planned equipment purchases, and anticipated business growth.

A gym chain expanding into three new locations faced this exact decision. They had $1.8 million in buildout costs across all three locations. Rather than claiming Section 179 on everything, they strategically allocated:

• $400,000 in Section 179 deductions to the most profitable location with highest state conformity
• Bonus depreciation on $800,000 in qualifying components where state rules were unfavorable
• Regular depreciation on $600,000 in improvements at a location that had lower income

This strategy optimized both federal and state tax outcomes while preserving Section 179 capacity for equipment purchases planned for the following year.

Conclusion

Section 179 leasehold improvements give you control over one of your biggest business expenses. Instead of watching hundreds of thousands slowly depreciate over decades, you can reclaim that cash immediately and reinvest it in growth.

The rules are specific, the documentation requirements are real, and the state complications exist. But the cash flow impact makes it worth getting right. Whether you’re building out your first retail space or renovating your tenth medical office, understanding Section 179 puts you ahead of most business owners who leave this money on the table.

Work with qualified professionals—your CPA for tax strategy and a specialized cost segregation firm for property analysis. The combination ensures you’re claiming every dollar you’re entitled to while staying completely compliant with IRS requirements. Your buildout is expensive enough. Don’t pay more taxes than necessary because you didn’t know these rules existed.

Section 179 Leasehold Improvements FAQs

Citations

• CSSI Services. (2025). Maximizing Tax Benefits Through Leasehold Improvements
• Claimyr. (2025). Understanding Qualified Leasehold Improvements for Tax Deductions
• Schwartz & Schwartz. (2025). OBBB Strategy: Section 179 Is No Longer Just for Equipment
• Accounting Insights. (2025). Can You Use Section 179 for Leasehold Improvements?
• EisnerAmper. (2025). What Is Qualified Improvement Property (QIP)?
• Capstan Tax Strategies. (2025). Handle with Care: What Is and Is Not QIP
• Bloomberg Tax. (2024). Qualified Improvement Property
• MSC Tax. (2025). Understanding Qualified Improvement Property: A Guide for Real Estate Owners and CPAs
• Hagene, Brian & Cook, Mark G. (2024). Planning Opportunities: Sec. 179 Expensing vs. Bonus Depreciation
• The Tax Adviser. (2021). Qualified Improvement Property and Bonus Depreciation
• CLA. (2025). Section 179 Bonus Depreciation Examples and Tax Strategies
• Westwood Net Lease. (2025). Bonus Depreciation For CRE Being Phased Out
• DiSanto, Priest & Co. (2024). Bonus Depreciation and Section 179 Update Deductions
• Kahn Litwin Renza. Cost Segregation & Section 179: Maximize Tax Savings
• Wipfli. (2024). Consider Cost Segregation Study to Buy or Build Real Estate
• The Tax Adviser. (2020). Cost Recovery Changes in the TCJA
• RSM US. Confusion Over Qualified Leasehold Improvements May Create Opportunity
• Section179.org. (2025). Section 179 by State – Conformity Rules and Tax Differences