A study can start with three documents: your closing statement, your current depreciation schedule, and the property address. Everything else on the list below makes the result more precise, more defensible, or both.
Missing documents are not a reason to delay. They change the engineer's method, not the validity of the result. Here is the full request list, why each item earns its place, and what happens when you cannot produce it.
The short answer - Two documents are non-negotiable: the settlement statement that proves your basis, and the depreciation schedule that shows what you have already deducted. - Everything else has a workaround. With no cost records, the engineer uses the IRS Audit Techniques Guide's cost estimate approach, an accepted methodology. - Construction records are the single biggest upgrade to a study, because they move you from estimated costs to actual costs. - A land appraisal can pay for the study by itself, since land is never depreciable and every dollar kept out of that bucket can be reclassified.
The Full Document List, and What Each One Does
| Document | Why it matters | What happens without it |
|---|---|---|
| Settlement / closing statement | Establishes total cost, closing date, and which closing costs capitalize into basis | No workaround. This is the foundation |
| Purchase and sale agreement | Reveals any contractual allocation to land, building, or personal property | Engineer allocates using an appraisal or assessor ratio |
| Appraisal | Strongest support for the land carve-out | Falls back to the county assessor's land ratio |
| Property tax assessment card | Independent land ratio, year built, square footage | Pulled from public records; costs a day, not a dollar |
| Depreciation schedule, Form 4562, fixed asset detail | Shows what has been claimed; drives the catch-up on a look-back | No workaround on a look-back study |
| Construction cost records: pay applications, schedule of values, change orders, final cost breakdown | Enables the detailed engineering approach from actual cost records | Study shifts to the cost estimate approach |
| Architectural and structural drawings | Quantities, areas, finish schedules, structural versus non-structural | Engineer measures and photographs on site |
| Mechanical, electrical, plumbing drawings | Separates dedicated equipment power and specialty plumbing from base building | Engineer reads panel schedules and observes connections in the field |
| Civil and site plan | Paving, curbs, site utilities, drainage, landscaping | Aerial imagery plus on-site measurement |
| Rent roll or unit mix | Unit counts, finish levels, in-unit versus common area assets | Statistical sampling during the site visit |
| Capital improvement history with dates and amounts | Correct placed-in-service years, QIP eligibility, disposition candidates | Improvements get buried in building basis and the benefit is lost |
| Prior cost segregation studies | Prevents reclassifying the same dollars twice | Real risk of double-counting, which examiners look for |
The Three Documents That Start the Clock
You do not need the whole list to begin. Send the settlement statement, the depreciation schedule, and any appraisal, and an engineer can model the property within days.
The settlement statement does more work than owners expect. It fixes the placed-in-service date, which fixes your bonus depreciation percentage, and it identifies capitalizable items such as title fees and transfer taxes that belong in basis rather than in expense.
The depreciation schedule tells us what you have already taken. On a look-back study for a building you bought in a prior year, it is the starting point for the catch-up computation.
If You Built or Renovated It, Cost Records Change the Method
The IRS Cost Segregation Audit Techniques Guide, Publication 5653, revised February 2025, describes six methodologies. The detailed engineering approach from actual cost records is the most reliable and the most defensible, and it is available only when you can produce the underlying cost detail.
That means pay applications with the schedule of values, executed change orders, the contractor's final cost breakdown, and your direct-purchase invoices for signage, security systems, or specialty equipment. Soft costs count too: architect fees, permits, and general conditions get allocated pro rata across the asset classes instead of landing entirely in the building.
If you have these, say so early. They produce a cleaner reconciliation of allocated costs to actual costs, one of the thirteen principal elements the ATG expects in a quality study.
What Happens When a Document Simply Does Not Exist
Most acquisitions of older buildings come with no construction records at all. The seller does not have them, the contractor is long gone, and the drawings were never scanned.
That is normal, and it is why the ATG blesses the detailed engineering cost estimate approach. The engineer visits the site, measures and photographs the components, takes off quantities, and prices them using published construction cost data adjusted for local rates and for the placed-in-service year. The result reconciles back to your actual total cost.
The method is different. The rigor is not. For the full sequence from kickoff to report, see how a cost segregation study actually works.
Example: What One Appraisal Was Worth on a $3,200,000 Strip Center
Example: a $3,200,000 retail strip center, closed March 2026 The county assessor's card implied land at 25% of value. A lender-ordered appraisal completed at closing supported land at $560,000, or 17.5%. Both are defensible sources. Only one was in the owner's file at kickoff.
| Land allocation source | Land value | Depreciable basis | Reclassified at 25% | First-year deduction at 100% bonus |
|---|---|---|---|---|
| Assessor ratio (25%) | $800,000 | $2,400,000 | $600,000 | $600,000 |
| Lender appraisal (17.5%) | $560,000 | $2,640,000 | $660,000 | $660,000 |
Producing one document the owner already had moved $60,000 of deduction into year one, roughly $21,000 of cash at a combined 35% rate. We do not pick the friendlier number. We pick the best supported one and document why, as explained in how land allocation is determined. Your result depends on your tax rate and whether you can use passive losses.
The Two Documents We Genuinely Cannot Work Around
Everything above has a substitute except these two.
Proof of basis. A study allocates a known total. Element eleven of the ATG's quality standards is a reconciliation of allocated costs back to actual total costs, and without a settlement statement, a title closing package, or a complete capitalized construction total, that reconciliation cannot be done. Title companies retain closing files, so this is usually a phone call rather than a dead end.
Your existing depreciation schedule on a look-back. The catch-up depends on the gap between depreciation claimed and depreciation that should have been claimed. Guessing at the first number is not an option. If a prior CPA holds the fixed asset detail, request it before the engagement starts.
Everything else, we can build.
Frequently Asked Questions
Do I need drawings to get a study?
No. Drawings sharpen quantities, but an engineer can measure the building. What they genuinely improve is the mechanical and electrical allocation, since dedicated circuits and specialty plumbing are hard to trace without a panel schedule. Check the county permit file before assuming they are gone.
What if I bought the building five years ago and never did a study?
Nothing on the checklist changes. You need the original settlement statement, every depreciation schedule since, and the improvement history. The correction happens on a current-year return through an accounting method change rather than amended returns, the mechanic covered in what cost segregation is.
Does the engineer need to visit the property?
For an engineering-based study, yes, in nearly every case. The site visit is where components are identified, measured, and photographed, and that photo record becomes part of the defense file.
How long does gathering documents usually take?
Most owners assemble the core package in one to two weeks. The long pole is almost always the capital improvement history, so start pulling that first.
See What Your Property Would Yield
Every building is different, and the only way to know your number is to look at your building. Precision Cost Segregation provides a no-cost feasibility analysis: send us the property address, purchase price, closing date, and any improvements, and we'll model your likely reclassification and first-year benefit before you commit to anything.
Request a free feasibility analysis →
This article is provided by Precision Cost Segregation for general educational purposes and does not constitute tax, legal, or accounting advice. Tax outcomes depend on your specific facts, your tax rate, your passive activity position, and your entity structure. Figures shown are illustrative. Consult your CPA or tax advisor before acting, and engage a qualified professional to perform any cost segregation study. Information is current as of publication.
This article is general information, not tax or legal advice. Depreciation outcomes depend on your facts, elections, and current law — consult your CPA before acting. © 2026 Precision Cost Segregation.