A new deck off the back of a rental does not get its own short recovery period, and the place most self-managers go wrong is assuming it does. The deck looks like a separate thing you bolted on, so it feels like it should depreciate faster than the house. It does not. An attached deck or porch is an addition to the building, which means it rides the same 27.5-year straight-line schedule as the structure it is attached to.
The rule is short, but two distinctions decide whether you handle it right: whether the work is a new addition or a repair, and whether the structure is attached to the building or sitting at grade on its own. Get those two calls correct and the rest is arithmetic.
The class life: 27.5 years as a building addition
IRS Pub 527, Table 1-1 lists Deck, Porch, and Patio directly under the heading Additions. Pub 527 then states that an addition or improvement is depreciated over the same recovery period as the property it is added to, determined as if the addition were placed in service when the addition itself was. For a residential rental that recovery period is 27.5 years under the general depreciation system, the same number that governs the building on the building's own 27.5-year schedule.
So a deck you finish in June is its own line of depreciable property with its own in-service date, but the recovery period and method match the house: 27.5 years, straight line, mid-month convention. The mid-month convention treats the asset as placed in service in the middle of the month it was completed, so the first year is a partial year. Say you complete a $9,000 deck in June. The first-year factor is (6.5 remaining months ÷ 12) ÷ 27.5, which works out to about 1.970 percent, roughly $177 the first year. After that it settles into the full annual slice of $9,000 ÷ 27.5, about $327 a year, until it is fully recovered.
Attached addition vs. detached land improvement
This is the distinction that actually moves money, and it is where the stale posts get it backwards. An attached deck or porch, bolted to the house and sharing its structure, is a building addition at 27.5 years. The 15-year land improvement bucket is reserved for site work that sits on the land rather than the building: a freestanding patio at grade, a paved walkway, retaining walls, or fencing. Even those land improvements turn on the facts, but an attached deck rarely qualifies.
The temptation is obvious. A 15-year life recovers your cost almost twice as fast as 27.5 years, so calling the deck a land improvement looks like a win. It is the kind of aggressive classification that reads fine until an examiner pulls the build photos and sees the deck framed into the rim joist of the house. If you want to break a property into shorter-lived components on purpose, that is a cost segregation study, done with an engineer, not a guess on a deck. For most small landlords the study does not pay on a single deck.
When the deck is a repair, not an addition
Not every dollar you spend on a deck gets capitalized. Replacing a few rotten boards, swapping out a failing railing, or re-staining and sealing the surface is repair and maintenance: you deduct it in the year you pay it, in full, against that year's rental income. Re-staining in particular is plain upkeep. Do not roll the cost of a stain job into the deck's basis, because you would be stretching a same-year deduction across 27.5 years for no reason.
The flip happens when you rebuild. Tearing out the old deck and framing a new one is a restoration: it brings a new structure into service, so it is capitalized and starts its own 27.5-year schedule from the completion date. The test is whether you kept the existing deck working or replaced it. Patching is a repair; rebuilding is an addition. The same logic runs through every component on the property, which is why classifying repairs vs. improvements is the call that drives your whole Schedule E.
How it lands on your return
A capitalized deck shows up on Form 4562 in the year you place it in service and flows to depreciation on line 18 of Schedule E. A deck repair shows up as a repair expense on line 14 in the year you pay it. Same physical structure, two completely different lines, two completely different timelines for the deduction. Tracking the in-service date and the building basis for each addition is what keeps line 18 honest, and it is exactly the kind of detail a year of receipts tends to lose.
If you want the running tally done for you, this is the part of the job I built rents.ai to handle: when you flag a deck rebuild as a capital expense, it spins that cost into its own depreciation schedule and keeps line 18 current as the years roll. It will not classify the expense for you, though. You still have to decide whether the work was a repair or an addition, and you still hand the totals to your CPA. A reasonable cross-check is the depreciation calculator to confirm the first-year mid-month factor before anything reaches the return.
This is general information to help you organize your year for your CPA, not tax advice. The governing source is IRS Pub 527 (Table 1-1 for additions and Table 2-1 for recovery periods). Confirm the classification of any specific deck with your tax preparer before you file.