Industrial Real Estate Is Five Different Businesses in One Zoning Category

From the outside, "industrial" sounds like one thing.

Big buildings. Loading docks. Trucks. The kind of real estate nobody romanticizes.

But once I started working through the actual categories — the types, the tenant profiles, the underwriting — it became obvious that "industrial" is really five different businesses that happen to share a zoning designation.
Each one targets a different kind of user.
Each one requires a different site.
Each one carries a different investment risk profile.

Industrial real estate isn't a single asset class — it's five different businesses sharing a zoning category, and the underwriting question for each is whether the building's supply-chain position matches the tenant logic of that specific type. The developer who understands those distinctions builds for the right user in the right place. The one who doesn't ends up with space that matches the wrong supply-chain role — and that mismatch shows up in the lease-up, not in the pro forma.

That gap is what I wanted to work through here. Not just what the categories are, but what the differences tell you about how to actually underwrite them.

A map of the five types

The clearest way to get oriented is to put all five types next to each other and see what varies.

Three things stand out right away.

First, office percentage drops sharply as you move from flex-tech toward warehouse. A flex-tech building might be nearly half office. A warehouse building is mostly open bay with just enough management space to run the operation.

Second, rent is not highest where the building is biggest. Self storage and flex-tech charge more per square foot than warehouse distribution, even though warehouse buildings are often ten times larger. That's because rent reflects what the space does for the tenant, not the raw volume of it.

Third, every type runs triple net — except self storage, which is gross. That one exception matters, and I'll come back to it in the next post.

I find it useful to think of the first three as the "making" side of industrial and the last two as the "moving and storing" side. They share a zoning category but operate with completely different fundamentals. This post covers the first three. The next one covers the other two and the break-even math that ties it all together.

Flex-Tech / R&D: the space for companies still figuring it out

Flex-tech is the most office-like of the industrial categories.

A typical building might have 35,000 square feet of actual office space with an equal-sized lab or light manufacturing area behind it — a configuration that doesn't fit cleanly into office or industrial, which is precisely why this product type exists. The name "flex" captures it well: you can flex between what's office and what's production depending on who moves in.

The location logic makes sense once you see who's actually using it.

These buildings cluster near universities because a lot of their tenants are startup businesses actively hunting for engineering and research talent. They show up in suburban industrial parks because that's where zoning allows the hybrid mix of office and light production.

In San Diego, the Miramar Road corridor is a good example — so is the Sorrento Valley area along the 15. These aren't downtown locations. They're zones where a biotech startup can have its research team in the front, a prototype lab in the back, and a loading door for equipment at the side — and pay meaningfully less than Class A office rent per square foot.

The demand driver is relatively direct: when the economy is expanding and R&D spending is up, companies need this kind of space. When contracts slow down or firms pull back, occupancy softens. That sensitivity means flex-tech is more cyclical than it looks — it rides the R&D spending cycle, not just the general office market.

What I found worth sitting with is the investment logic here. The building is straightforward. The tenant underwriting is where it gets hard.

The investment bet behind flex-tech and IMT

Here's the thing about signing a lease with a startup biotech or a first-time business owner: you're not just betting on a building. You're betting on a business.

A five-year lease with a company that goes under in twelve months is not a five-year lease. It's twelve months of rent followed by a vacant space and re-leasing costs — which, for a space needing buildout reconfiguration, can be substantial.

The questions you're asking a flex-tech or IMT tenant are not that different from what a VC firm asks before writing a check. Does the business model make sense? Where is the revenue coming from? Who's backing them? What happens if the economy turns and they lose a major contract?

Not every tenant will be a winner. Some developers lean into this explicitly — they know that if they fill a 100-unit incubator building, maybe 90 of those businesses will stay small or fail over the lease term. But 10 might actually succeed and grow, and those are the ones who need more space. If you're a developer who also has larger industrial product available, you can be their next landlord too.

That's essentially the incubator logic applied to real estate — and it only works if you've done real due diligence on the businesses you're signing.

Incubator / Multi-Tenant: the space built to be outgrown

Incubator multi-tenant space — IMT, in the shorthand — is a close cousin of flex-tech, but the design philosophy is different.

The buildings look similar: two-story, low-rise, suburban location, 25–50% office finish. But the interior is built around a specific idea about how tenants grow.

IMT buildings are designed so that a tenant starting with 2,000 square feet can knock through a wall and take 4,000 when their neighbor vacates. The implicit design goal is to be the on-ramp — the first real space for a small business — with the expectation that some of those businesses will eventually need to move up to something larger.

Demand here is closely tied to business formation. When the economy is producing new companies, IMT space fills. When business creation slows, it empties. Rent runs slightly below flex-tech on a per-square-foot basis — $1.20 to $1.65 NNN — but the buildings are smaller and serve more tenants per square foot of total building.

The management overhead is higher. More tenants means more lease administration, more turnover, more relationship-managing. But the upside is that you're not dependent on any single tenant or any single business surviving.

Manufacturing: the space where things actually get made

Manufacturing space is where industrial real estate starts to look genuinely different from anything else.

The buildings are one story, almost always.
The office component drops to between five and fifteen percent.
The rest is production floor.

That physical configuration is driven by the work happening inside: overhead cranes, heavy equipment, production lines that run the length of the building, and materials moving in and product moving out through a series of bay doors.

In San Diego, most heavy manufacturing concentrates in three places: Oceanside at the north end of the county, National City and Chula Vista near the border in the south, and Otay Mesa as the primary cross-border industrial zone.

That geography isn't random.

Defense contractors cluster here because San Diego has the highest concentration of military installations in the country. The Navy and Marines are the customer base, and proximity to the customer matters as much here as it does for office tenants choosing a CBD location. Electronics manufacturers follow the same logic — Qualcomm and the firms in its supply chain want to be close to each other.

The Mexico border corridor exists because cross-border production runs are common. A component gets manufactured on one side, shipped across, assembled with other components, shipped back for finishing, and sent to market. That supply chain logic makes Otay Mesa valuable for a specific kind of manufacturer in a way that no other industrial market in San Diego can replicate.

The underwriting question manufacturing requires

Flex-tech asks whether a startup can survive long enough to pay rent. Manufacturing asks something different: where in the supply chain does this company sit?

A company making a commodity component — something any factory in the world could produce — is vulnerable. Their contract could move offshore, get automated out, or go to a cheaper competitor who just entered the market. A company doing specialty manufacturing — something only they can produce at the right quality, using equipment or knowledge it took years to develop — is much more defensible.

The other question is where they sit in the supply chain relative to the finished product. The closer a manufacturer is to the finished good that customers actually buy, the more valuable their position. A company two steps removed from the end product can get cut out if someone else figures out a better integration. The final assembler has leverage that upstream suppliers don't.

That doesn't mean contract manufacturers make bad tenants — it means the underwriting has to account for that fragility. Is the contract long-term? Is there more than one customer? What happens if the dominant customer renegotiates the contract?

These are the questions a lender or equity partner will ask, and the developer needs answers ready before signing.

Like the other types, manufacturing leases are always triple net: the tenant pays operating expenses, taxes, and insurance on top of base rent. That structure simplifies the developer's income model. But it doesn't simplify the business analysis the developer has to do before the lease gets signed.

The part that changed how I think about tenant underwriting

The framing that stuck with me most is the supply chain positioning question.

"Where are you in the supply chain?" sounds like a due diligence question. But it's actually a strategy question.

A company that can answer it clearly — that can point to proprietary equipment, a process they've spent ten years refining, a position in the supply chain nobody can easily step into — is a company worth betting on as a landlord.
A company that can't answer it clearly, or whose answer amounts to "we make the thing everyone else makes, but for cheaper," is a company whose lease carries real downside risk.

That reframe matters because it applies to all three types on the "making" side of industrial.
The biotech startup in flex-tech either has a defensible research direction or it doesn't.
The IMT tenant either has a real business model or they're running on hope.
The manufacturer either owns a process nobody else has or they're one contract renegotiation away from a problem.

In each case, the building is the easy part. The business behind the lease is where the actual underwriting happens.

A few things I'm taking away

• The label "industrial" covers five fundamentally different businesses — each with its own location logic, tenant profile, and investment risk
• Office percentage is a reliable signal of what kind of work is happening inside: as it drops from 40% toward 5%, you move from knowledge work toward physical production
• Flex-tech and IMT demand the same kind of business due diligence as early-stage investing — most tenants will stay small, but a few will grow fast, and developers with multiple product types can capture that growth
• San Diego's industrial geography is determined by two forces: proximity to military bases and proximity to the Mexico border, and those two forces define where each category clusters
• Specialty manufacturing makes a better tenant than contract manufacturing, for the same reason a patent makes a better competitive moat than a cost advantage
• Triple net leases across all three types shift expense risk to the tenant — that simplifies the income model but doesn't eliminate the underwriting work
• The supply chain position question is the most useful single question for manufacturing tenant underwriting: the closer to the finished product, the more defensible the business

This post is part of my ongoing series on real estate development — Real Estate Development. Earlier posts cover the development process, entitlements, pro forma feasibility, multifamily economics, affordable housing, office, and senior housing. The next post covers warehouse distribution, self storage, and break-even rent.