Capital improvements raise your adjusted basis, which lowers your taxable gain when you sell or exchange. Whether a project counts as a capital improvement - one that adds value, extends life, or adapts the property's use - or as a repair that merely maintains current condition decides whether it adds to basis or becomes a current-year deduction. Get that classification wrong and you overpay.
Why basis matters for your exchange
A new roof, a gut-remodeled bathroom, a full plumbing replacement: each is money you sank into a property, and each quietly lowers the tax you'll owe when you sell or exchange it. On a property held 15 years or more, improvements the owner never tracked can add up to $30,000 to $80,000 in basis - and $10,000 to $30,000 in tax paid for no reason.
The lever is your adjusted basis, the foundation of every tax calculation in a 1031 exchange:
Gain = Amount realized (sale price minus selling costs) - Adjusted basis
A higher basis means a smaller gain, and a smaller gain means less tax to defer - or to pay, if the exchange falls through. Every legitimate capital improvement you've made adds to that basis. Owners who don't track their improvements carry a lower basis than they're entitled to and report a gain larger than the real one.
Capital improvement vs. repair
The IRS draws a line between improvements, which are capitalized to basis, and repairs, which you deduct as a current expense. The test comes from the tangible property regulations under IRC Section 263(a).
Capital improvement - adds to basis:
- Betterment: makes the property materially better than its original condition
- Restoration: returns a worn component to like-new condition, or rebuilds after a casualty
- Adaptation: puts the property to a new or different use
Repair - current deduction:
- Keeps the property in its current operating condition
- Fixes something broken without materially upgrading it
- Is routine and recurring
The line sometimes feels subjective because it is. Replacing a few broken shingles is a repair; replacing the entire roof is an improvement. Patching drywall is a repair; gutting and rebuilding a bathroom is an improvement.
Common improvements and their classification
Work performed | Classification | Basis impact |
|---|---|---|
New roof | Improvement | Adds to basis |
Roof patch/repair | Repair | Current deduction |
Full HVAC system replacement | Improvement | Adds to basis |
HVAC tune-up or component repair | Repair | Current deduction |
Kitchen remodel (new cabinets, counters, layout) | Improvement | Adds to basis |
Replace broken garbage disposal | Repair | Current deduction |
New addition (bedroom, garage) | Improvement | Adds to basis |
Repaint exterior | Repair | Current deduction |
Replace all plumbing | Improvement | Adds to basis |
Fix a leaking pipe | Repair | Current deduction |
New landscaping/hardscaping | Improvement | Adds to basis |
Mow lawn, trim hedges | Repair/maintenance | Current deduction |
Convert garage to ADU | Improvement (adaptation) | Adds to basis |
Replace broken window | Repair | Current deduction |
Install new windows (all) | Improvement | Adds to basis |
How improvements affect exchange math
Say you bought a rental for $350,000 and held it for 12 years. Along the way you replaced the roof ($18,000), remodeled both bathrooms ($22,000), and installed a new HVAC system ($12,000) - $52,000 in capital improvements.
| Without improvements tracked | With improvements tracked |
|---|---|---|
Purchase price | $350,000 | $350,000 |
Capital improvements | $0 | $52,000 |
Total basis before depreciation | $350,000 | $402,000 |
Depreciation (simplified) | $122,182 | $140,509 |
Adjusted basis | $227,818 | $261,491 |
Sale price (net) | $520,000 | $520,000 |
Taxable gain | $292,182 | $258,509 |
Tax at ~30% effective rate | $87,655 | $77,553 |
Tax difference |
| $10,102 less |
The owner who tracked those improvements defers roughly $10,000 less in tax, and, more to the point, holds records that stand up in an audit. The one who didn't either overreports the gain or scrambles to reconstruct the paper trail under pressure.
Documentation requirements
Keep records of every improvement:
- Receipts and invoices. The contractor's invoice showing the work performed, date, and amount paid.
- Canceled checks or bank statements. Proof of payment.
- Before and after photos. Visual evidence of the improvement's scope.
- Permits. Building permits document the nature and timing of work.
- Your own records. A simple spreadsheet listing each improvement with date, description, cost, and contractor.
If you've lost records for older work, reconstruct what you can. Bank and credit card statements from those years may show payments to contractors. County permit records are public. Contractors may have records going back years.
Improvements on replacement property
When you acquire a replacement property through a 1031 exchange and later improve it, those improvements start their own depreciation schedule based on when you place them in service, not the date of the exchange. They're treated as new assets with fresh depreciation clocks.
That's separate from the carryover basis on the building itself. Your CPA should track the exchange carryover basis and any post-acquisition improvements as separate depreciation schedules.
Improvement (build-to-suit) exchanges, where you use exchange funds to improve the replacement property, follow more complex rules and require specific structuring through what's called an exchange accommodation titleholder, or EAT. See our improvement exchange guide for the details.
Capital improvements are free basis - money you've already spent that reduces your taxable gain. Kept from the day you buy, the receipts, permits, and photos that prove them translate directly into tax savings when you sell or exchange. If records for older work are gone, reconstructing what you can before listing is still worth the effort.
Frequently asked questions
What if I did the improvements myself (sweat equity)?
You can capitalize the cost of materials, not the value of your own labor. Spend $5,000 on materials and do the work yourself, and your basis increase is $5,000.
Do improvements before a 1031 exchange affect the replacement property requirement?
No. Improvements to the property you're selling raise your basis and reduce your gain, but they don't change the rule that your replacement property must be equal or greater in value than the sale price.
What about the de minimis safe harbor?
Under the tangible property regulations, you can elect to expense - deduct in the current year - items costing $2,500 or less per invoice, or $5,000 if you have audited financial statements. So a $2,000 appliance could be deducted as a repair instead of capitalized. The tradeoff is a deduction now against a lower basis at sale. Your CPA can advise on which election serves you better.