A signed purchase contract starts a clock. On most commercial deals you get 30 to 60 days to confirm everything the seller and the offering memorandum told you, and your lender runs its own checks in the same window. Commercial real estate due diligence is where deals get repriced, restructured, or killed. It’s also where most closing delays start. Here’s what to review, what your lender will order, and where I see borrowers get caught.
What Is Commercial Real Estate Due Diligence?
Commercial real estate due diligence is the investigation period between contract and closing where you verify the property’s legal, physical, environmental, and financial condition. If something material turns up, the due diligence contingency in your purchase agreement usually lets you renegotiate or walk away with your deposit.
Two parallel processes run during this window:
- Your diligence as the buyer. You’re testing whether the deal you underwrote actually exists: the rents, the expenses, the condition of the roof, the zoning.
- Your lender’s diligence. The lender orders third-party reports (appraisal, environmental, property condition, survey, title) to confirm the collateral supports the loan.
The smart move is to run these as one process, not two. Most of the reports a lender requires are the same reports you should want anyway. Coordinate early and you avoid paying for the same work twice.
How Long Does the Due Diligence Period Last?
Most commercial contracts set a due diligence period of 30 to 90 days, with 45 to 60 days common for stabilized properties. Larger or more complex deals (multi-tenant retail, older industrial, anything with environmental history) can stretch longer.
Here’s what doesn’t get talked about enough: your due diligence period and your financing contingency are often two different dates. If your contract gives you 30 days of diligence but third-party reports take three to four weeks to come back, you could be past the point of a refundable deposit before your lender has even seen the appraisal. I push every client to align those dates before signing, or to negotiate an extension right.
The Commercial Real Estate Due Diligence Checklist
This is the commercial real estate due diligence list I walk borrowers through. Not every item applies to every property, but skipping one should be a deliberate decision.
Financial and Lease Review
- Rent roll: Current tenants, unit or suite, rent, lease dates, deposits. Tie it to bank deposits, not just the seller’s spreadsheet.
- Trailing 12-month and 2-3 years of operating statements: Look for expense items that are missing or understated, like management fees, reserves, and insurance.
- Leases and amendments: Read the actual documents. Renewal options, termination rights, co-tenancy clauses, and expense reimbursement terms all affect value.
- Estoppel certificates: Signed tenant confirmations of rent, term, and any defaults. Most lenders require them from major tenants.
- SNDAs: Subordination, non-disturbance, and attornment agreements, which your lender will typically want from anchor or single tenants.
- Property tax history and reassessment risk: A sale can trigger reassessment in many states. Model the post-sale tax bill, not the seller’s.
During commercial real estate due diligence, your lender will rebuild the property’s net operating income from these documents. If your numbers don’t match theirs, the loan amount shrinks.
Legal and Title
- Title commitment: Confirms ownership and shows liens, easements, and restrictions that will survive closing.
- ALTA/NSPS Land Title Survey: The survey standard most commercial lenders require. It shows boundaries, improvements, easements, encroachments, and flood zone.
- Zoning report or municipal letter: Confirms the current use is legally permitted and whether the building is legal non-conforming. That matters if it ever burns down.
- Certificates of occupancy and open permits: Unpermitted work is a lender problem and a future-you problem.
- Entity documents: Your borrowing LLC’s operating agreement and good-standing certificates. Lenders need these for closing.
Physical and Environmental
- Property condition assessment (PCA): A third-party report on the roof, structure, HVAC, and building systems, with estimated immediate repairs and a long-term capital plan. Lenders often size required repair escrows directly from this report.
- Phase I Environmental Site Assessment: Reviews historical use, government databases, and a site visit for signs of contamination.
- Flood zone determination: Pulled against the current FEMA map.
- Seismic or wind reports: Required in certain markets and by certain capital sources.
What Reports Will Your Lender Order?
The lender’s third-party package varies by loan type, but this table covers what I usually see:
| Report | Bank / credit union | SBA 504 or 7(a) | CMBS / agency | Bridge / private |
|---|---|---|---|---|
| Appraisal | Required | Required | Required | Required (sometimes BPO for small loans) |
| Phase I ESA | Usually | Depends on property use (see below) | Required | Often, or database screen |
| Property condition report | Larger loans | Case by case | Required | Case by case |
| ALTA survey | Usually | Usually | Required | Sometimes waived |
| Zoning report | Sometimes | Sometimes | Required | Sometimes |
| Estoppels / SNDAs | Major tenants | Owner-user: N/A | Required | Major tenants |
Borrowers pay for these reports, typically upfront, and the cost is non-refundable even if the deal dies. On a smaller commercial loan, the full third-party package can run anywhere from several thousand dollars to well into five figures depending on property type and size.
Why Environmental Review Carries So Much Weight
Within commercial real estate due diligence, environmental review is the one area where a problem can follow you long after you sell. Under federal Superfund law, a property owner can be liable for contamination they didn’t cause. The protection is performing “all appropriate inquiries” before you buy.
The EPA’s All Appropriate Inquiries rule recognizes the ASTM E1527-21 Phase I standard as satisfying that requirement. Several key components of the Phase I must be completed or updated within 180 days before acquisition. An older report pulled off the seller’s shelf won’t protect you or satisfy most lenders.
SBA loans have their own rules. The SBA’s SOP 50 10 requires an environmental investigation on commercial real estate collateral, and properties with current or past environmentally sensitive uses (gas stations, dry cleaners, auto repair, and similar NAICS codes) require a full Phase I regardless of loan size. If you’re buying your business’s building with an SBA 504 loan, check the property’s history before you’re under contract.
Flood is the other environmental item that catches people. FEMA’s mandatory purchase requirement means federally regulated lenders must require flood insurance on buildings in a Special Flood Hazard Area. Get a quote early. On some coastal and riverfront properties, flood premiums change the debt service coverage math.
What This Looks Like on a Real Deal
From a recent deal: I recently worked with a business owner buying a 22,000-square-foot flex industrial building in the Southeast for his HVAC distribution company, financed with SBA 504. The Phase I flagged a former auto body shop on the parcel from the 1980s, which triggered a Phase II with soil borings. That added about three weeks. Because we’d negotiated a 60-day diligence period with a 15-day extension option up front, my client had room to wait for results. The Phase II came back clean, the loan closed, and he didn’t have to put his deposit at risk while the lab work ran.
That deal closed on time because the commercial real estate due diligence calendar was built for a surprise before the contract was signed.
Buying a commercial property and worried about the diligence timeline? We structure acquisition financing nationally and coordinate third-party reports from day one. Schedule a 15-minute call →
Where Commercial Real Estate Due Diligence Goes Wrong
In my experience, deals rarely fall apart because of one big discovery. They slip because of avoidable friction:
- Ordering reports late. Appraisals and PCAs take two to four weeks in most markets. Order them the week you sign, not after you’ve “decided.”
- Trusting the seller’s numbers. Offering memorandum NOI is a marketing number. Lenders underwrite actual collections and add expenses the seller left out.
- Missing estoppel discrepancies. A tenant who signs an estoppel showing a lower rent, or claiming an unpaid tenant improvement allowance, changes your income and your loan amount.
- Ignoring the existing loan. If you’re assuming debt, the prepayment and assumption terms matter. See how commercial loan prepayment penalties work before you pick a path.
- Not budgeting for repair escrows. If the PCA calls for a new roof in year two, many lenders will hold back cash at closing. That’s equity you need to have.
If diligence uncovers a real problem, you have three moves: negotiate a price reduction or seller credit, require the seller to fix it before closing, or terminate within the contingency window. Sometimes the right answer is restructuring the financing. A commercial bridge loan can close a property with deferred maintenance or vacancy that a permanent lender won’t touch yet.
Frequently Asked Questions
What is included in commercial real estate due diligence?
It covers four areas: financial (rent roll, operating statements, leases), legal (title, survey, zoning, permits), physical (property condition assessment), and environmental (Phase I ESA, flood zone). Your lender will order its own third-party reports that overlap with most of these.
Who pays for due diligence on a commercial property?
The buyer does. That includes inspection costs, legal review, and the lender’s third-party reports, which are usually paid upfront and aren’t refundable if the deal doesn’t close.
How long is the due diligence period for commercial real estate?
Usually 30 to 90 days, set in the purchase agreement. For financed deals, I recommend at least 45 days so third-party reports come back before your deposit goes hard.
Can I back out of a commercial purchase during due diligence?
Typically yes, if your contract includes a due diligence contingency and you give written notice before it expires. After that deadline, your earnest money is usually at risk.
Ready to finance your commercial acquisition?
We’re a commercial mortgage brokerage serving investors, developers, and business owners nationally, with active lender relationships across bank, credit union, SBA, CMBS, agency, and bridge capital sources. Send us your scenario and we’ll respond within one business day with realistic terms and a clear list of what the lender will need during diligence.
This article is for informational purposes only and does not constitute financial, legal, or tax advice. Loan terms, rates, and availability vary by borrower, property, and market conditions. Consult Willowbrook Capital for scenario-specific guidance.
