The importance of Engineered Studies in Commercial Real Estate

What a cost segregation study does

When you buy, build or improve commercial property, you recover the cost through depreciation. By default, nonresidential real property is depreciated on a straight line over 39 years, and residential rental property, including apartment buildings with 5+ units, over 27.5 years. That default treats the frame, the carpet, the parking lot and the security system as if they all last as long as the structure.

They do not, and the tax code recognizes it. Personal property and land improvements have their own, shorter recovery periods. A cost segregation study identifies those components, assigns a supportable cost to each one, and moves them out of the building's life and into the class where they belong:

• 5-year property: carpet and specialty flooring, decorative lighting, dedicated electrical and plumbing that serve equipment, data and security cabling, furnishings, and many process-related systems.
• 7-year property: certain equipment, furniture systems and specialized machinery-related assets.
• 15-year property: land improvements such as paving, curbing, sidewalks, site lighting, fencing, landscaping, signage and site drainage, and qualified improvement property inside nonresidential buildings.
• 27.5- or 39-year property: the structure and its general building systems, which is what remains.

A study does not create new deductions. Over the life of the property you deduct the same total cost either way. What changes is when. Moving deductions out of the later decades of ownership and into the early years frees up cashflow while you hold the asset, and that cash can go into operations, debt paydown or the next acquisition.

Why timing matters now

Property in the 5-, 7- and 15-year classes is eligible for bonus depreciation, and 100% bonus depreciation is back and permanent for qualifying property acquired after January 19, 2025. Every component a study moves out of the structure can then be deducted in full in the year it is placed in service, rather than spread across its recovery period. Without a study, most of a commercial building sits in a life that bonus depreciation cannot reach. How bonus depreciation works with a study.

Manufacturers and other production facilities have a second, newer opportunity. Qualified production property under §168(n) can allow the production portion of a nonresidential building itself to be deducted in the year it is placed in service, if the property and the activity meet the requirements. Separating the production space from offices, parking and other excluded areas is an engineering exercise too. Qualified production property studies.

Not every study is an engineered study

The IRS publishes a Cost Segregation Audit Technique Guide that examiners use to evaluate studies. It describes several methodologies, and it is clear that they are not equally reliable.

• Detailed engineering approach from actual cost records. Costs come from the project's own documents, such as closing statements, plans, pay applications and invoices, and the building is inspected to confirm what was actually installed. The Guide regards this as the most methodical and accurate approach.
• Detailed engineering cost estimate approach. Used when actual cost records are not available, typically on an acquisition. Components are inventoried from the property and priced from recognized cost sources, then reconciled to the basis.
• Survey or letter, residual estimation, sampling or modeling, and rule-of-thumb approaches. These rely on someone else's classification, on values for a handful of items with everything else left in the building, on percentages borrowed from other properties or a software model, or on a generic allocation. They sit at the weak end of the spectrum and draw the most scrutiny.

The difference shows up when a study is examined. An engineered study can show where every number came from: the document it was taken from, the photograph of the component, the quantity counted and the method used to price it. A modeled or rule-of-thumb study cannot, because that support was never created.

What an engineered study involves

Our process runs in four steps, in this order:

• Engineering-prepared estimate. Commercial estimates are prepared by Engineering and held to a deeper investigation than other firms, with fixed-fee pricing and a written proposal in 24 to 48 hours.
• Information collection. Closing statement, plans, pay applications, photos and prior returns, sent through a secure upload. NDAs are available for sensitive projects.
• Site tour. Virtual or Onsite Tour options, chosen to suit the property.
• Report and deliverable. Every study is signed off by the Head of Engineering before it is delivered.

Typical turnaround is 3 to 5 weeks, including the site tour, information collection and study creation, given good collaboration. See the full process.

Why Seneca specializes in commercial

Commercial property is a different engineering problem from a single-family rental. The buildings are component-dense, site work is often a large share of the basis, and many systems exist to serve tenants, equipment or a production line rather than the structure. The questions owners and their CPAs ask are different as well: how a truck court is treated, which electrical and mechanical capacity serves a process, how a mixed-use building is split between residential and nonresidential use, and how a catch-up is reported on Form 3115. The documentation burden rises with the size of the deduction.

• Engineering has completed studies for every commercial property type, from hotels to lumber mills, and the engineering team has completed 900+ commercial property studies.
• Commercial estimates are prepared by Engineering and held to a deeper investigation than other firms.
• The engineering training program is very selective for commercial projects.
• Every study is signed off by the Head of Engineering.
• We are one of the only firms in the USA that can do a Production Property Study under §168(n).
• Our founders are real estate investors who use cost segregation on their own deals.

Across Seneca, that adds up to 10,200+ studies completed and $1B+ in cost basis analyzed. This site is where the commercial work lives: all commercial property, and residential buildings with 5+ units. If you own 1 to 4 unit residential property or short-term rentals, senecacostseg.com is the right place to start.

If you already missed it

Owning a building for years without a study does not forfeit the deduction. A look-back study calculates the depreciation you could have claimed since the property was placed in service, and the cumulative difference is generally taken in the current year through an automatic change in accounting method on Form 3115, without amending prior returns. Your CPA files and signs the form and adds the taxpayer information. We prepare everything else, the narrative, the form, the calculations and the supporting schedules, and work directly with your CPA throughout.

Backed for as long as you own it

Every study includes lifetime audit defense for the taxpayer and the property while under their ownership. That covers responding to IRS information requests about the study at the agent and appeals level, answering for workpapers, photos and methodology questions, and correcting the report if the IRS finds an error on our side. A money-back guarantee also applies; see the Terms of Service for details.