About the Author
This guide was written by Matthew Gigantelli, a cost segregation engineer who has completed engineered studies on over 3,000 properties, including hundreds of new construction and renovation projects. Gigantelli holds a B.A. in Finance (summa cum laude) from Rasmussen University and a certification from Boon Tax Educators (2026).
Matthew Gigantelli on construction studies: "Construction and renovation studies are where cost segregation delivers the highest ROI. When you have actual invoices, the engineer does not need to estimate costs from RS Means — the real numbers are right there. But only if you tracked them correctly. The difference between organized documentation and a shoebox of receipts can be $10,000-$50,000 in missed deductions."
Why Construction and Renovation Studies Are Different
Most cost segregation studies are acquisition studies — the investor bought an existing property and the engineer estimates component costs using RS Means construction cost data. That works, but it is an estimate.
Construction and renovation studies use actual costs. When you build or renovate a property, you have invoices, pay applications, and contractor breakdowns that show exactly what was spent on each component. This is the gold standard for cost segregation because:
- Actual costs are more defensible than estimates. The IRS prefers real invoices over RS Means estimates.
- You capture every dollar. Acquisition studies can miss components that are not visible during a site visit. Construction invoices capture everything — including underground work, embedded systems, and components that get covered up.
- Indirect costs are documented. Permits, architectural fees, engineering fees, and construction management costs are on the invoices. No estimation needed.
- Renovation costs can be separated from the existing building. This allows partial asset disposition on replaced components — an additional deduction most investors miss entirely.
Your closing disclosure and appraisal establish the depreciable basis for the acquisition portion, while the construction cost ledger covers the renovation portion.
According to Matthew Gigantelli: "A construction study on a $500,000 renovation typically reclassifies 25%-35% of costs to accelerated categories — higher than the 20%-28% typical for acquisition studies. The reason is simple: renovation work disproportionately involves 5-year and 15-year components like flooring, cabinets, fixtures, landscaping, and paving." For benchmark data on typical allocation percentages across 45 property types, see our cost segregation benchmarks from 8,000+ studies.
What Your Cost Segregation Engineer Needs from You
Before diving into how to track costs, here is the complete document checklist your engineer will request. Having these ready saves weeks of back-and-forth.
Required Documents
| Document | Why It Is Needed | When to Provide |
|---|---|---|
| Closing Disclosure or Settlement Statement | Confirms exact sale price, sale date, and property address. Establishes the depreciable basis for the acquisition portion. | At study engagement |
| Construction Cost Ledger | Organizes all renovation/construction costs by component category with room detail, dates, and invoice references. This is the primary cost source for the study. | At study engagement |
| Property Listing or Photo Tour | Provides visual documentation of the property's current condition, finishes, and components. Video walkthroughs are preferred for interior spaces. | At study engagement |
Required for Condos
| Document | Why It Is Needed |
|---|---|
| CC&Rs (Covenants, Conditions, and Restrictions) | Confirms the unit definition and what the owner actually owns vs. what is common area. Critical for condos because site improvements (parking, landscaping) may belong to the HOA, not the unit owner — which changes the 15-year allocation. |
Helpful but Optional
| Document | Why It Is Helpful |
|---|---|
| Appraisal | Provides independent property valuation, land allocation, and condition assessment. Helps the engineer validate the depreciable basis and land percentage. |
| Architectural Drawings or Plans | Helps with quantity take-offs and identifying components not visible during inspection. |
| Contractor Bids or Proposals | Provides scope-of-work detail that invoices sometimes lack. |
The Construction Cost Ledger: How to Track Every Dollar
The construction cost ledger is the single most important document for a construction or renovation cost segregation study. It organizes every dollar spent into categories that map directly to MACRS recovery periods.
Here is the complete ledger structure your engineer needs, with guidance on what goes in each category.
How the Ledger Works
The ledger has columns for:
- Asset — the component or work description
- Cost — the dollar amount from the invoice
- Scope — what was done (replaced, added new, repaired)
- Room Detail — where in the property the work was performed
- Date Completed — when the work was placed in service (this determines the depreciation start date)
- Invoice — reference number for the supporting document
Indirect Costs Section
These are costs associated with the entire project, not a specific component. They get allocated proportionally across all improvements.
| Line Item | What It Includes | MACRS Treatment |
|---|---|---|
| General demolition | Demo costs for the overall project | Allocated proportionally |
| Permits | Building permits, electrical permits, plumbing permits | Allocated proportionally |
| Temporary utilities | Temporary power, water, portable toilets during construction | Allocated proportionally |
| Overhead and profit | General contractor markup | Allocated proportionally |
| Professional service fees | Architect, engineer, designer fees | Allocated proportionally |
| General labor | Day labor, cleanup crews, general helpers | Allocated proportionally |
| General supplies | Fasteners, adhesives, caulk, tape, drop cloths | Allocated proportionally |
| General equipment rentals | Dumpsters, scaffolding, lifts | Allocated proportionally |
Matthew Gigantelli: "Most investors throw indirect costs into a single bucket and depreciate everything over 27.5 years. That is wrong. Indirect costs get allocated proportionally to every component — including 5-year and 15-year property. On a $100,000 renovation with $12,000 in indirect costs, proper allocation adds $2,000-$4,000 to your accelerated deductions."
Miscellaneous Structural and Finishes
| Line Item | Typical MACRS Life | Notes |
|---|---|---|
| Interior wall repairs and finishing | 27.5/39-year | Structural — unless purely cosmetic |
| Interior removable wall finishes (wallpaper, paneling) | 5-year | Removable finishes are personal property |
| Ceiling repair and finishing | 27.5/39-year | Structural |
| Removable trim and moldings | 5-year | Decorative, removable |
| Exterior wall repairs and finishing | 27.5/39-year | Structural |
| Roof repair and finishing | 27.5/39-year | Structural |
Flooring
| Line Item | Typical MACRS Life | Notes |
|---|---|---|
| Indirect flooring costs | Allocated | Subfloor prep, leveling compound |
| Flooring labor and installation | 5-year | All flooring types (carpet, vinyl, tile, hardwood) are 5-year personal property |
| Moisture barrier | 5-year | Associated with the flooring system |
| Subfloor repairs | 27.5/39-year | Structural — part of the building |
Key detail: The ledger asks "What was removed? What was replaced?" This matters for partial asset disposition. If you replaced existing carpet with luxury vinyl plank, you can write off the remaining undepreciated value of the old carpet in addition to depreciating the new flooring. Your engineer needs to know what was removed to calculate this.
Kitchen
| Line Item | Typical MACRS Life | Notes |
|---|---|---|
| Indirect kitchen costs | Allocated | General demo, prep work |
| Cabinetry and countertops | 5-year | Personal property — removable |
| Appliances | 5 or 7-year | Ranges, refrigerators, dishwashers, microwaves |
| Plumbing rough | 27.5/39-year | Behind-wall plumbing is structural |
| Plumbing fixtures | 5-year | Faucets, sinks, garbage disposals |
| General purpose lighting | 27.5/39-year | Serves as the primary lighting source of the room |
| Decorative lighting | 5-year | Not the primary lighting source — pendant lights, under-cabinet lights |
| Kitchen remodel (lump sum) | Split | If tracked as a single line item, the engineer must estimate the split. Tracking by component is always better. |
The lighting distinction is critical. General purpose lighting (the main ceiling fixture that lights the room) is structural — 27.5 or 39-year property. Decorative lighting (pendant lights over an island, under-cabinet LED strips, accent lighting) is 5-year personal property. The ledger separates these because the MACRS treatment is different.
Restroom
| Line Item | Typical MACRS Life | Notes |
|---|---|---|
| Indirect restroom costs | Allocated | General demo, prep work |
| Cabinetry and countertops | 5-year | Vanities, countertops |
| Plumbing rough | 27.5/39-year | Behind-wall plumbing |
| Plumbing fixtures | 5-year | Faucets, toilets (decorative), vessel sinks |
| Mirror | 5-year | Removable — personal property |
| General purpose lighting | 27.5/39-year | Primary room lighting |
| Decorative lighting | 5-year | Vanity sconces, accent lighting |
Additional Categories (Not Shown in Template)
A complete construction cost ledger should also include:
| Category | Line Items | Typical MACRS Life |
|---|---|---|
| Exterior / Site | Paving, concrete flatwork, fencing, retaining walls, landscaping, irrigation, exterior lighting, drainage | 15-year |
| Electrical | Panel upgrades (39-yr), dedicated circuits for appliances (5-yr), decorative fixtures (5-yr), security/alarm systems (5-yr), data cabling (5-yr) | Split |
| HVAC / Mechanical | Furnace/AC replacement (39-yr), ductwork (39-yr), exhaust fans (5-yr), dryer vents (5-yr), specialty ventilation (5-yr) | Split |
| Windows and Doors | Window replacement (39-yr), exterior doors (39-yr), interior doors (5-yr if decorative/removable) | Mostly 39-yr |
| Specialty | Pool/spa (15-yr), fire suppression (39-yr), elevator (39-yr), built-in audio/visual (5-yr) | Varies |
Example: $150,000 Renovation Tracked Correctly
Here is what a properly tracked renovation looks like, and how it translates to accelerated depreciation:
| Category | Cost | MACRS Life | Accelerated? |
|---|---|---|---|
| Kitchen cabinets and countertops | $18,000 | 5-year | Yes |
| Kitchen appliances | $4,500 | 7-year | Yes |
| Kitchen plumbing fixtures | $2,200 | 5-year | Yes |
| Kitchen decorative lighting | $1,800 | 5-year | Yes |
| Kitchen general lighting | $600 | 27.5-year | No |
| Kitchen plumbing rough | $3,500 | 27.5-year | No |
| Bathroom vanities and countertops (x3) | $9,000 | 5-year | Yes |
| Bathroom plumbing fixtures | $3,600 | 5-year | Yes |
| Bathroom mirrors | $1,200 | 5-year | Yes |
| Flooring throughout (LVP) | $14,000 | 5-year | Yes |
| Interior paint | $8,500 | 5-year | Yes |
| Removable trim and moldings | $3,200 | 5-year | Yes |
| Window treatments (blinds) | $2,800 | 5-year | Yes |
| Exterior landscaping | $12,000 | 15-year | Yes |
| Driveway repaving | $8,500 | 15-year | Yes |
| Fencing | $6,500 | 15-year | Yes |
| Exterior lighting | $3,200 | 15-year | Yes |
| Roof replacement | $15,000 | 27.5-year | No |
| HVAC replacement | $12,000 | 27.5-year | No |
| Window replacement | $9,500 | 27.5-year | No |
| Electrical panel upgrade | $4,500 | 27.5-year | No |
| Permits and fees | $3,400 | Allocated | Proportional |
| General contractor overhead | $12,000 | Allocated | Proportional |
| Total | $159,500 |
Result after proper allocation:
| Category | Amount | % of Total |
|---|---|---|
| 5-Year Personal Property | $72,800 | 45.6% |
| 7-Year Personal Property | $4,500 | 2.8% |
| 15-Year Land Improvements | $30,200 | 18.9% |
| 27.5-Year Real Property | $51,900 | 32.5% |
| Total | $159,500 | 100% |
Accelerated depreciation: $107,500 (67.4% of total renovation cost) qualifies for 5-year, 7-year, or 15-year recovery. With 100% bonus depreciation, the entire $107,500 is deductible in Year 1.
At a 37% tax rate, that is approximately $39,800 in first-year tax savings from the renovation alone — on top of any savings from the original acquisition basis.
Matthew Gigantelli: "Renovation studies routinely produce 60%-70% accelerated allocation because renovation work is dominated by finishes, fixtures, and site improvements — all of which are 5-year or 15-year property. Compare that to 20%-28% for a typical acquisition study. If you are doing a BRRRR strategy and not getting a construction cost segregation study on the rehab, you are leaving the biggest deduction on the table." If you're renovating a short-term rental, our STR design ROI analysis covers how renovation decisions affect both guest revenue and tax strategy.
Construction Study vs. Acquisition Study: Key Differences
| Factor | Acquisition Study | Construction / Renovation Study |
|---|---|---|
| Cost source | RS Means estimates | Actual invoices and pay applications |
| Typical accelerated allocation | 20%-28% | 25%-35% (renovation can reach 60%-70%) |
| Indirect cost documentation | Estimated from industry rates | Actual permits, fees, and overhead from invoices |
| Partial asset disposition | Not applicable (no prior components) | Available for every replaced component |
| IRS defensibility | Strong with RS Means + site visit | Strongest — actual costs are the gold standard |
| Documentation burden | On the engineer (RS Means lookup) | On the investor (must track costs by component) |
Partial Asset Disposition: The Deduction Most Investors Miss
When you renovate a property, you are not just adding new components — you are replacing old ones. Under IRS regulations (Treas. Reg. 1.168(i)-8), you can dispose of the old component and deduct its remaining undepreciated value in the year of replacement.
Example: You bought a property 3 years ago for $400,000. The original carpet (part of the 27.5-year building) had an allocated cost of $6,000. After 3 years of straight-line depreciation, the remaining undepreciated value is approximately $5,345. When you replace the carpet during renovation, you can deduct that $5,345 as a partial asset disposition — in addition to depreciating the new flooring as 5-year property.
This is why the construction cost ledger asks "What was removed? What was replaced?" Your engineer needs this information to calculate the disposition deduction for every replaced component.
The BRRRR Strategy and Cost Segregation
The Buy-Rehab-Rent-Refinance-Repeat (BRRRR) strategy is one of the highest-ROI applications of cost segregation because it combines two studies:
- Acquisition study on the original purchase price — reclassifies 20%-28% of the existing building
- Construction study on the renovation costs — reclassifies 60%-70% of the rehab spend
Example at $300,000 purchase + $150,000 renovation:
| Component | Basis | Accelerated % | Accelerated Amount |
|---|---|---|---|
| Acquisition (existing building) | $240,000 (after 20% land) | 24% | $57,600 |
| Renovation (construction study) | $150,000 | 67% | $100,500 |
| Total | $390,000 | 40.5% | $158,100 |
At 37% tax rate with bonus depreciation: approximately $58,500 in first-year tax savings.
Without cost segregation, the entire $390,000 depreciable basis would be spread over 27.5 years ($14,182/year), producing only $5,247 in first-year tax savings. The difference is over $53,000 in Year 1. For the complete playbook on combining the BRRRR method with cost segregation — including refinance timing, hold-period optimization, and multi-property scaling — see our dedicated BRRRR method cost segregation tax strategy guide.
Common Mistakes in Construction Cost Tracking
1. Lump-Sum Invoices
A contractor invoice that says "Kitchen renovation — $35,000" is nearly useless for cost segregation. The engineer cannot determine how much was cabinets (5-year), how much was plumbing rough (27.5-year), and how much was appliances (7-year). Always request itemized invoices or break down lump sums in your ledger. The distinction between what counts as a repair (currently deductible) versus a capital improvement (depreciated over time) adds another layer of complexity — see our guide on repairs vs. improvements for rental property taxes for the IRS framework on that determination.
2. Missing Indirect Costs
Permits, architectural fees, and general contractor overhead are deductible — but only if they are documented and allocated. Many investors track component costs but forget to include the $3,000 in permits and the $15,000 in GC markup.
3. No "Before" Documentation
Partial asset disposition requires knowing what was there before the renovation. Take photographs of the existing property before any demolition begins. Document the existing flooring, cabinets, fixtures, and site conditions.
4. Mixing Personal and Rental Expenses
If you live in the property part-time or use it personally, only the rental-use portion qualifies for cost segregation. Keep personal-use expenses completely separate from the construction cost ledger.
5. Not Tracking Dates
The "placed in service" date determines when depreciation begins. If your renovation spans multiple tax years, components placed in service in different years must be depreciated separately. Track completion dates for each category.
Frequently Asked Questions
Q: Can I do cost segregation on a renovation or remodel?
A: Yes. Cost segregation applies to any capital improvement to a rental or commercial property, not just the original purchase. Renovation and construction studies often produce higher accelerated allocations (60%-70%) than acquisition studies (20%-28%) because renovation work disproportionately involves 5-year and 15-year components like flooring, cabinetry, fixtures, landscaping, and paving. The key requirement is tracking costs by component category rather than as lump sums.
Q: What is a construction cost ledger for cost segregation?
A: A construction cost ledger is a spreadsheet that organizes every renovation or construction cost by component category (flooring, kitchen, restroom, electrical, site work, indirect costs), with columns for cost, scope of work, room detail, completion date, and invoice reference. It maps directly to MACRS recovery periods, allowing the cost segregation engineer to classify each dollar into 5-year, 7-year, 15-year, or 27.5/39-year property. Using a ledger instead of submitting raw invoices typically increases accelerated deductions by 15%-25% because it ensures no component is missed or misclassified.
Q: What is partial asset disposition?
A: Partial asset disposition (under Treas. Reg. 1.168(i)-8) allows property owners to deduct the remaining undepreciated value of a building component when it is replaced during a renovation. For example, if you replace 10-year-old carpet that still has 17.5 years of depreciation remaining, you can deduct the remaining undepreciated value in the year of replacement — in addition to depreciating the new flooring. This deduction is available for every replaced component (flooring, cabinets, HVAC, roofing, etc.) and is one of the most commonly missed deductions in real estate. For a complete walkthrough of how disposition works, see our partial asset disposition guide.
Q: Is cost segregation worth it for a small renovation under $100,000?
A: For renovations above $50,000 on a rental property, cost segregation almost always produces meaningful savings. A $75,000 renovation with 65% accelerated allocation produces approximately $48,750 in bonus depreciation — worth approximately $18,000 in tax savings at a 37% rate. Even with a technology-enabled study costing a fraction of traditional firm pricing, the ROI is typically 5x-10x or higher. For renovations under $30,000, the savings may not justify the study cost unless combined with an acquisition study on the original purchase.
Q: What documents does my cost segregation engineer need for a construction study?
A: The four essential documents are: (1) Closing Disclosure or settlement statement (confirms purchase price and sale date), (2) Construction cost ledger with costs organized by component category, (3) Property photos or video tour showing current condition, and (4) CC&Rs if the property is a condo. Optional but helpful documents include the appraisal, architectural drawings, and contractor bids. Having organized documentation ready at engagement typically reduces study turnaround time by 1-2 weeks.
Q: How does cost segregation work with the BRRRR strategy?
A: The BRRRR (Buy-Rehab-Rent-Refinance-Repeat) strategy benefits from two cost segregation studies: an acquisition study on the original purchase price (reclassifying 20%-28% of the existing building) and a construction study on the renovation costs (reclassifying 60%-70% of the rehab spend). Combined, a $300,000 purchase with a $150,000 renovation can produce approximately $158,000 in accelerated depreciation — worth approximately $58,500 in first-year tax savings at a 37% rate. The construction study is where most of the value comes from, which is why tracking renovation costs by component is critical.
For a quick cost segregation estimate on your property, try Modern CFO's free calculator. For construction-specific cost segregation strategies, see Modern CFO's construction and renovation cost segregation guide.
See Your Property's Tax Savings
Drop your address — the AI estimates your depreciation savings in 60 seconds, backed by a certified engineer study.
Free cost segregation estimate, engineer-certified studies, and ongoing depreciation tracking.
Backed by $1B+ in supported tax depreciation.