Roof replacements

A new roof is where every rule in this pillar collides on one invoice. It is expensive, it is common, and its tax treatment is a small maze: is it a repair or an improvement, can you write off the old roof, and which first-year deduction, if any, applies. Get it right and a big cash outlay throws off real deductions. Get it wrong and you depreciate it slowly for 39 years while still carrying the dead roof on your books.

Repair or improvement: usually improvement

Start with the classification, because it drives everything downstream. Patching a section of roof after a storm is generally a repair, deductible now. Replacing the entire roof is generally a restoration, one of the three triggers in the improvement test, so it must be capitalized. Most full roof replacements are improvements.

The exception is scale. A roof is judged against the building’s structure, and whether you have replaced enough of it to count as a restoration depends on how much you did relative to the whole. Replace a small portion and it may be a repair; replace the roof and it is a restoration. When it lands on the improvement side, the next questions open up.

Patching a roof is usually a deductible repair; replacing the whole roof is usually a capitalized improvement, and that classification sets up everything that follows.

Do not forget the old roof

Once the new roof is an improvement you capitalize, the partial asset disposition comes into play, and it is the piece owners most often miss. You just spent, say, $60,000 on a new roof. But you may still have undepreciated basis in the old roof from your original purchase. Without a disposition election, you now depreciate both: the new roof and the ghost of the old one, for years.

Elect the partial asset disposition, and you write off the old roof’s remaining basis as a loss this year. That single election can turn a chunk of a capitalized roof into an immediate deduction, offsetting part of the sting of capitalizing the new one. The catch, as always, is knowing the old roof’s basis, which is where a cost-segregation study done at acquisition pays off years later.

When you capitalize a new roof, elect a partial asset disposition to write off the old roof, or you will depreciate two roofs at once.

Which first-year deduction, and the commercial-versus-residential split

Now the new roof itself. Can you deduct it fast, and the answer splits by property type in a way that surprises people.

A roof is generally 27.5 or 39-year property, above the 20-year line, so it usually does not qualify for bonus depreciation. That is the default disappointment: the new roof is a slow-clock asset.

But Section 179 carves out an exception, and only for commercial property. Roofs on nonresidential buildings are eligible for Section 179 expensing, up to the annual limit, if placed in service after the building was. So a commercial owner can often expense a new roof under Section 179 even though bonus depreciation cannot touch it. A residential landlord generally cannot, because roofs on residential rental property are not Section 179 property. This is one of the sharpest places the commercial-versus-residential line changes the answer to the same question.

A new commercial roof can often be expensed under Section 179; a new residential roof usually cannot, so the same roof gets very different treatment depending on the building.

Putting it together

One roof replacement, done with the whole toolkit: classify the new roof (usually a capitalized improvement), elect a partial asset disposition to write off the old roof’s remaining basis as a current loss, and then, if the building is commercial and you have the income, expense the new roof under Section 179. A residential owner without the 179 route still gets the disposition loss and begins depreciating the new roof. Either way, the difference between doing this deliberately and doing it by default is thousands of dollars in the year of the work.

The bottom line

• A full roof replacement is usually a capitalized improvement, not a deductible repair.
• Elect a partial asset disposition to write off the old roof’s remaining basis, or you depreciate two roofs.
• A roof is above the 20-year line, so it generally does not qualify for bonus depreciation.
• Commercial roofs can often be expensed under Section 179; residential roofs generally cannot.
• The pieces interact, so a roof project is worth planning before the work, not after.

For the write-off on the old roof, read partial asset dispositions. For the two first-year deductions, see Section 179 vs bonus depreciation. For the full picture, start at the depreciation and cost segregation hub.

Last verified August 2026.