Capital Improvements & Depreciation in Co-Owned Property
Real Amigos Team · March 6, 2026 · 9 min read
The Myth That Costs Co-Owners Thousands
Ask anyone who co-owns property what happens when one person pays for a new roof, and you will almost always hear the same answer: "That person owns more of the house now." It sounds right. It feels right. And it is partially right. But the full truth is more complicated, and getting it wrong can cost co-owners thousands of dollars over the life of their partnership.
The prevailing assumption, repeated across real estate forums and even by some professionals, is that a capital improvement permanently increases the paying co-owner's equity stake. One popular piece of advice on a Real Estate Sub-Reddit puts it plainly: "When one person puts in more for renovations, it's usually easiest to treat that amount as added equity for them. Just make sure it's written down clearly." End of discussion. No mention of what happens to that equity five, ten, or twenty years later.
But here is the hidden truth: a capital improvement does not hold its full value forever. A roof installed today will not be worth the same amount in 2046. A kitchen remodel that feels brand new right now will look dated in a decade. The equity that a capital improvement creates depreciates over time, and if co-owners are not tracking that depreciation, their equity calculations are wrong. When equity calculations are wrong, income splits are wrong, cost-sharing is wrong, and buyout valuations are wrong.
What Makes a Capital Improvement Different
Not every dollar spent on a property is a capital improvement. Fixing a leaky faucet is maintenance. Replacing the entire plumbing system is a capital improvement. The distinction matters because capital improvements are what the IRS and the real estate industry call expenses that add value to the property, extend its useful life, or adapt it to a new use.
For co-owners, capital improvements are unique because they are dual contributions. Every capital improvement has two distinct financial components:
The equitable component is the portion of the cost that actually raises the property's value and therefore builds equity for the person who paid. If you spend $50,000 on a new roof and half of that cost goes toward raising the property's market value, then $25,000 gets credited to your ownership stake.
The non-equitable component is the remainder, the portion that does not build equity. This is a shared operational expense, divided among all co-owners based on their equity percentages at the time the payment is made. It works the same way interest, insurance, and other shared costs are divided: if you own 55% of the property, you are responsible for 55% of the non-equitable portion.
The split between the equitable and non-equitable amount varies among improvements, and depends entirely on how much of the cost actually raises the property's value. And this is where it gets interesting.
Some Improvements Are Worth More Than They Cost
The equitable-to-non-equitable split varies by improvement type, and in some cases, the equitable component can actually exceed the total cost of the improvement.
This is the concept employed by people who flip houses. A few targeted upgrades, a modernized kitchen, fresh landscaping, updated fixtures, and the property's market value jumps by more than the cost of the work. A $30,000 kitchen remodel might increase the home's appraised value by $45,000. On the other end of the spectrum, some improvements add less value than they cost. A highly customized home theater or a pool in a market where pools are not valued might cost $40,000 but only raise the property's appraised value by $20,000. In that case, the equitable component is $20,000 and the remaining $20,000 is a non-equitable shared expense.
The key principle: A capital improvement is a dual expense, composed of both an equitable component and a non-equitable component.
The Part Nobody Talks About: Depreciation
Here is where the conventional wisdom falls apart completely. That $25,000 in equity credit from the new roof? It does not stay at $25,000.
A roof has a useful life. Depending on the materials, it might last 25 to 30 years. Every day that passes, the roof is one day closer to the end of its useful life, and the equity it created depreciates accordingly.
Consider the math on a $50,000 roof with a 30-year useful life, where 50% of the cost ($25,000) is the equitable component:
| Time Elapsed | Remaining Equity Credit | Depreciation to Date |
|---|---|---|
| Day 1 | $25,000 | $0 |
| Year 1 | $24,167 | $833 |
| Year 5 | $20,833 | $4,167 |
| Year 10 | $16,667 | $8,333 |
| Year 15 | $12,500 | $12,500 |
| Year 20 | $8,333 | $16,667 |
| Year 30 | $0 | $25,000 |
That $25,000 equity credit erodes at roughly $2.28 per day. After 15 years, half of it is gone. After 30 years, it has depreciated entirely. The person who paid for the roof still benefited from the equity credit for three decades, but the credit was never permanent.
Now consider a kitchen remodel. A $35,000 renovation with a 15-year useful life and an equitable component of $25,000 depreciates much faster:
| Time Elapsed | Remaining Equity Credit | Depreciation to Date |
|---|---|---|
| Day 1 | $25,000 | $0 |
| Year 1 | $23,333 | $1,667 |
| Year 5 | $16,667 | $8,333 |
| Year 10 | $8,333 | $16,667 |
| Year 15 | $0 | $25,000 |
Same initial equity credit, but it disappears twice as fast because a kitchen remodel has a shorter useful life than a roof.
How Depreciation Should Be Tracked
The depreciation of a capital improvement should be tracked continuously, not calculated retroactively when a dispute arises or a sale is imminent. Here is what proper tracking looks like:
Record the improvement at the time it happens. Document the total cost, the equitable component (how much it raises the property's value), the non-equitable component (the shared expense portion), and the estimated useful life.
Calculate daily depreciation. The equitable component depreciates on a daily basis over the useful life of the improvement. For a $25,000 equitable component with a 30-year useful life, that is approximately $2.28 per day.
Settle depreciation periodically. Accumulated depreciation should be reconciled among co-owners at regular intervals to keep equity percentages current and income and cost distributions accurate. Like any other non-equitable expense, depreciation is shared in proportion to each co-owner's equity stake at the time of settlement. Adjust equity calculations in real time. As depreciation accumulates, each co-owner's equity percentage shifts. These shifts should be reflected in how rental income is distributed and how shared costs are allocated.
Account for depreciation at sale or buyout. When the property is sold or one co-owner exits, the final equity calculation should include all accumulated depreciation on every capital improvement up to that point.
Why This Matters: The Ripple Effect on Everything Else
Depreciation is not just an accounting detail. It has real consequences for every financial aspect of co-ownership, because equity percentages determine how income and costs are distributed.
If you are tracking equity correctly, each co-owner's percentage tells you two critical things at any given moment: how much of the property's rental income they are entitled to, and how much of the property's shared costs they are responsible for. Get the equity percentage wrong, and both of those calculations are wrong too.
Here is a concrete example. Marcus and Elena buy a rental property together, each contributing equally to the down payment. After two years of equal mortgage payments, they each own 50% of the equity. Then Marcus pays $50,000 for a new roof. The equitable component is $25,000.
On the day the roof is installed, Marcus's equity jumps. Let's say the total equity in the property is $200,000. Before the roof, Marcus owned $100,000 (50%). After the equitable credit, Marcus owns $125,000 out of $225,000 total, giving him roughly 55.6% equity. Elena owns 44.4%.
This means Marcus is now entitled to 55.6% of rental income and responsible for 55.6% of shared costs. Elena's share drops to 44.4% on both sides.
But if Marcus and Elena are not tracking depreciation, they will still be using that 55.6/44.4 split five years later, even though the roof's equity credit has depreciated by $4,167. The correct split at the five-year mark would be closer to 53.7/46.3. Over five years of rental income, that 1.9% difference adds up. On a property generating $3,000 per month in rent, Marcus would have received roughly $3,420 more than he was entitled to, and Elena would have received $3,420 less.
Extend that over 15 or 20 years without correcting for depreciation, and the numbers become significant.
What Co-Owners Actually Get Wrong
Browse any real estate forum where co-owners discuss capital improvements, and you will find the same mistakes repeated:
Treating improvement costs as permanent equity. This is the most common error. A co-owner pays for a renovation, adds the full cost to their equity column, and never adjusts it. Ten years later, they are claiming equity credit for an improvement that has lost most of its value.
Ignoring the equitable vs. non-equitable split entirely. Many co-owners treat the full cost of an improvement as equity-building, when in reality only a portion of the cost raises the property's value. The rest is a shared expense that should be divided proportionally.
Failing to account for depreciation at buyout. When one co-owner wants to sell their share, the buyout price should reflect the current depreciated value of all improvements, not the original cost. A co-owner who paid for a roof 20 years ago should not receive equity credit as if the roof were installed yesterday.
The Bottom Line
Capital improvements are one of the most powerful ways to build equity in co-owned property, but that equity is not permanent. It depreciates over the useful life of the improvement, and if co-owners are not tracking that depreciation, every financial calculation downstream is compromised.
The co-owners who get this right are the ones who track improvements from day one, understand the difference between equitable and non-equitable components, and account for depreciation continuously rather than pretending that a roof installed in 2026 will still be worth the same amount in 2056.
The ones who get it wrong? They end up on Reddit, asking strangers how to calculate equity splits that should have been tracked all along.
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