Once a commercial building closes, its problems are yours: the tenant who doesn't pay what the rent roll says, the easement under the parking lot, the dry cleaner that used to be next door. The due diligence period in the contract is the one window when you can still find those things and walk away, or reprice. This is the checklist for that window, for the buyer, the buyer's agent, and the broker who reviews the file.
Ask for the rent roll and the last twelve months' operating statement before you write a letter of intent, and redo three numbers yourself:
Then look for anything that ends the conversation early: a single tenant whose lease is about to end, visible deferred maintenance, a use the zoning doesn't allow, or a past use (a gas station, a dry cleaner, a machine shop) that makes an environmental problem likely. Check the flood zone on FEMA's flood map before you spend money on reports.
Put the list in the purchase agreement with a delivery date, so the clock doesn't run while you wait for paper.
| Document | What to check |
|---|---|
| Certified rent roll | Every tenant, rent, term, deposit and concession, and that it matches the leases line by line. |
| Every lease, amendment and side letter | Renewal and termination options, co-tenancy and go-dark clauses, exclusives, rights of first refusal, rent steps, and what expenses each tenant reimburses. |
| Operating statements (last 12 months and 2–3 years) | One-time income, missing expenses, and whether NOI is rising or falling. |
| Expense reconciliations (CAM) | Whether tenants actually paid their share, caps on what can be passed through, and any tenant audits or disputes. |
| Tax bills and assessments | What taxes will be after the sale; some places reassess on a sale. |
| Insurance policy and loss runs (5 years) | Roof, water and liability claims, and what coverage costs now. |
| Service contracts and warranties | What you inherit, what can be cancelled at closing, and which roof and equipment warranties transfer. |
| Permits, certificates of occupancy, code violations | That the building and each use are legal, and that nothing was built without a permit. |
| Existing survey, title policy, environmental and engineering reports | A head start on your own reports: how old they are, and whether you can rely on them. |
| Delinquency report and tenant correspondence | Who pays late, who has asked for relief, and who is in a dispute with the landlord. |
| Report | Why it matters |
|---|---|
| Title commitment | Schedule B lists what the title insurer won't cover: easements, liens, restrictions. Read every exception document, and object in writing before the contract's title deadline. |
| ALTA/NSPS land title survey | Boundaries, easements, access and encroachments on the ground. Surveys contracted on or after February 23, 2026 follow the 2026 standards, which add an optional encroachment summary table (Table A, Item 20). Order the Table A items your lender and title insurer need. |
| Phase I environmental site assessment | Done to ASTM E1527-21, it satisfies EPA's "all appropriate inquiries" rule (40 CFR Part 312), which a buyer needs to claim CERCLA's protections as an innocent landowner, contiguous property owner or bona fide prospective purchaser. It must be done within one year before you acquire the property, with the interviews, lien search, records review, site visit and the environmental professional's declaration within 180 days. |
| Property condition assessment | Roof, structure, mechanical systems, parking and life safety, with the cost of what needs fixing now and soon. ASTM E2018-24, in effect since January 1, 2024, is the current standard. |
| Zoning report | Whether the use is allowed, the parking count is legal, and any variance or nonconforming status survives the sale. |
| Tenant estoppel certificates | Each tenant's signed statement of its rent, term, deposit and any defaults. The rent roll's truth test, and usually a lender's condition. |
| SNDAs | Subordination, non-disturbance and attornment agreements: the lender's and the tenants' promises to each other if there is ever a foreclosure. |
| Appraisal and flood determination | Ordered by the lender: the value that supports the loan, and whether flood insurance is required. |
The buyer decides. The agent keeps the calendar, collects the documents and chases the deadlines, and says what they don't know rather than guessing at it. The attorney reads the contract, the title exceptions and the leases. The surveyor, the environmental professional and the engineer write the reports and sign them. The lender decides what the loan needs. A broker reviewing the file should see all of it before the due diligence period ends, not after closing.
PlainSight's real estate brokerage example shows fourteen agents' deals, a commercial desk, and what skipped steps cost the office, read the way a broker would read it. Everything runs in your browser.
Take the brokerage tour →This guide is general information for buyers, agents and brokers, not legal, tax, environmental or financial advice. Contracts, leases and state law decide the details; have each purchase reviewed by the professionals it needs.