Every commercial deal has two negotiations. The first sets the price. The second happens during due diligence, when the buyer's team goes looking for reasons the price was wrong. Sellers who understand what's coming keep their number. Sellers who don't, fund the discount.
Here's what a real due diligence process covers, drawn from the same institutional checklists buyers' consultants work from, and what each side should do about it.
The five workstreams
Physical condition. Building inspections covering roof, structure, mechanical, electrical, plumbing, and accessibility, plus a review of plans, certificates of occupancy, and maintenance history. Institutional buyers commission a Property Condition Assessment (PCA); in California, seismic review often rides along. What they're pricing: deferred maintenance and near-term capital needs, at their cost plus their margin.
The repairs a buyer finds in diligence always cost the seller more than the repairs a seller fixes before marketing.
Environmental. A Phase I environmental site assessment reviews current and historical uses for contamination risk. Dry cleaners, auto uses, and industrial history are the classic flags, and Orange County industrial has plenty of all three in its past. A clean Phase I is routine; a flagged one triggers Phase II testing, lender anxiety, and time. Sellers with any environmental history should know their story before the buyer writes it.
Financial. Three to five years of income and expense statements, tax bills, utility costs, capital expenditure history, aged receivables, and tenant recovery reconciliations. Buyers rebuild your operating statement from source documents, and every expense you under-reported becomes their negotiating exhibit.
Legal and title. Preliminary title report, ALTA survey, covenants, easements, and any litigation history. Most surprises here are old and curable: an easement nobody remembered, a lien that should have been released. Curable is fine; discovered-late is expensive.
Tenants and leases. Every lease and amendment, rent roll, security deposit ledger, payment history, and estoppel certificates from tenants confirming the lease terms. This is where multi-tenant deals wobble: a tenant who won't sign an estoppel, a side letter nobody disclosed, an option the rent roll forgot.
The timeline
A typical structure: 30 to 60 days of due diligence inside a 60 to 90 day escrow, with the buyer's deposit going non-refundable when the investigation period ends. Financing adds its own track, and SBA deals run longer. The discipline that matters is a dated checklist, because in escrow, every discovered problem after the contingency deadline is a negotiation, and every one before it is just information.
What this means for each side
Buyers: diligence is not a formality between handshake and keys; it's your last leverage and your only protection. Run it on a checklist with hard dates, order third-party reports early (they gate everything), and treat the estoppels as seriously as the inspection.
Sellers: run the diligence on yourself before the market does. Assemble the document package before marketing, fix cheap physical items, reconcile the financials, and surface the weird stuff early on your terms. A buyer who finds no surprises has nothing to reprice with. That preparation is step one and two of my disposition process, and it's where most of the value protection happens.
Reference framework: institutional due diligence checklists including Partner ESI's 2024 CRE Due Diligence Checklist.
FAQ
What is due diligence in commercial real estate?
The investigation period after a purchase agreement is signed, when the buyer verifies the property's physical condition, environmental status, financials, title, zoning, and leases before their deposit goes non-refundable.
How long does CRE due diligence take?
Typically 30 to 60 days for the investigation period, inside a 60 to 90 day escrow. Financing, especially SBA, and environmental findings can extend it.
What is a Phase I environmental site assessment?
A records-and-inspection review of a property's current and historical uses to identify potential contamination risk. Lenders require it on most commercial purchases; findings can trigger a more invasive Phase II.
What documents do sellers need for due diligence?
Expect requests for 3 to 5 years of income and expense statements, tax bills, rent rolls, all leases and amendments, service contracts, capital expenditure history, title documents, surveys, and building plans.
Keep reading
Is Now a Good Time to Buy a Building in the Coachella Valley?
The Coachella Valley market is showing concrete pricing signals that matter whether you're an owner-user looking to control your rent or an investor hunting yield in a second-home economy.
How Much Leverage Do I Really Have with My Landlord in Orange County?
Your leverage isn't just about your lease size. It's about what your landlord sees coming next, and that changes block by block across Orange County.
What Does a Broker Actually Do When Selling a Building in Orange County?
Most owners think a broker just lists the building and waits for offers. The actual work starts weeks before that and runs through every detail of diligence and escrow.