Roofing and Structural Components
Roofs, walls, floors, foundations, windows, and doors are listed structural components under Treas. Reg. §1.48-1(e)(2) and are generally section 1250 building property. Decorative roof elements can still be part of the roof. Qualified improvement property does not include roofs. Educational information, not tax advice.
Educational information, not tax advice.
Updated 2026-10-14
Key takeaways
- Section 1.48-1(e)(2) lists walls, partitions, floors, ceilings, permanent coverings, windows, doors, chimneys, stairs, and other components relating to operation or maintenance of a building.
- A building under section 1.48-1(e)(1) is a structure enclosing space, usually covered by a roof, used for shelter, housing, or working, office, parking, display, or sales space.
- Publication 5653 roof rows keep roofs with the building; decorative dormers or mansards that house wiring or whose removal exposes the building remain roof.
- Boddie-Noell treated mansard roof panels as listed structural components on those restaurant facts.
- Do not treat a roof as five-year property or as qualified improvement property; QIP is an interior nonresidential improvement class with statutory exclusions.
The building structure is not where cost segregation usually finds short-life property. Treas. Reg. §1.48-1(e)(1) defines a building as any structure or edifice enclosing a space within its walls, and usually covered by a roof, whose purpose is, for example, to provide shelter or housing, or to provide working, office, parking, display, or sales space. Examples include apartment houses, factories, offices, warehouses, barns, garages, and stores. Section 1.48-1(e)(2) then lists walls, partitions, floors, ceilings, permanent coverings such as paneling or tiling, windows and doors, chimneys, stairs, escalators, elevators, and other components relating to the operation or maintenance of a building. Tangible personal property excludes those items. Local fixture law does not control.
Hospital Corp. of America held that these tests apply under MACRS. The IRS acquiesced in the legal test, not in item results. AmeriSouth kept most claimed building components with 27.5-year apartments. L.L. Bean treated a rack system that supported roof and walls as a building even though it was theoretically movable. Whiteco’s six permanence factors are a court test for inherently permanent structures, not a statute, and they do not pull a roof off the building definition. A roof is how the building is a building.
Publication 5653 matrices treat roofs as building property. Decorative roof elements — false dormers or mansards — remain part of the roof when removal would expose the building or when they house lighting or wiring. Boddie-Noell held that items expressly listed as structural components were not investment-credit property and treated mansard roof panels that way on those restaurant facts. Shoney’s allowed decorative interior lighting, not the roof, and the IRS nonacquiesced in the lighting result. Ornament on a roof is still often the weather envelope.
Treas. Reg. §1.263(a)-3 distinguishes the building structure from listed building systems (HVAC, plumbing, electrical, elevators, fire protection, security, gas). The roof is part of the building structure unit of property for improvement testing. Replacing a roof is typically a restoration of that structure. A partial disposition election under Treas. Reg. §1.168(i)-8 can recognize remaining basis in the retired roof. Those rules do not create a five-year roof class.
Qualified improvement property under section 168(e)(6) is an improvement by the taxpayer to an interior portion of a nonresidential building placed in service after the building was first placed in service. It excludes enlargements, elevators and escalators, and internal structural framework. A roof is not an interior improvement. Publication 946 also discusses roofs in connection with section 179 qualified real property, which is an expensing election, not a five-year life. Do not stretch QIP onto the weather envelope.
What is the building
Walls, floors, foundations, the frame, the roof, windows, and doors are the core. Special-purpose structures that are essentially machinery, or that house integral-activity property and will be replaced with that property, are excluded from the building definition. Oil tanks, silos, and blast furnaces are the regulation’s examples. A warehouse and a garage are buildings.
Decorative roof work
A false dormer that is a sign cabinet may split like other signs under Whiteco or the casino pylon row. A mansard that is the roof edge remains roof in the matrices and in Boddie-Noell on those facts. Photograph whether removal exposes the building and whether the element houses wiring or lighting.
Parking structures and canopies are not this page
Stand-alone parking structures are buildings in Publication 5653 Chapter 8.B. Surface lots are class 00.3. Gasoline pump canopies are personal property in Rev. Rul. 2003-54; their footings are land improvements. None of those results reclasses a building roof.
Courts do not treat roofs as personal property
Unlike partitions, HVAC process units, or sprinkler heads, roofs are not a category where courts routinely split toward personal property. The splits in King Radio, Morrison, and Metro National concern interior systems and finishes. Using those cases to reclass a roof misreads both the regulation list and the building definition.
Documentation
Roof plans, section details, and photographs of decorative elements belong in the file if a study claims any roof-adjacent item as personal property. A roof replacement file should also separate the capitalization question from any partial-disposition election. Publication 5653 Chapter 4 expects a legal analysis and a cost reconciliation. Super Intelligence extraction is proposed. This page is educational information, not tax advice.
Sources
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- 4IRS Publication 946 — How To Depreciate Property (2025)(opens in a new tab)
Appendix B reproduces the Rev. Proc. 87-56 class lives.
- 5IRS Publication 5653 — Cost Segregation Audit Techniques Guide (rev. 2-2025)(opens in a new tab)
Written for IRS examiners. The guide states it is not an official pronouncement of law and cannot be cited as authority. It predates the July 2025 law.
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