The Break-Even Rent Is the Number That Keeps Industrial Development Honest

There was an article in the San Diego Union-Tribune about how much warehouse space Amazon is absorbing in the San Diego–Tijuana metro region.

The detail that stuck with me wasn't Amazon's size. It was the geography: Amazon just built a major distribution center across the border in Tijuana. Not San Diego — Tijuana. Because when you're building the logistics infrastructure to serve a population, the border is not a barrier. It's just a line on a map.

That's a good entry point into what makes the last two industrial categories — warehouse distribution and self storage — fundamentally different from the first three.

Flex-tech, incubator, and manufacturing space is demand-driven by what businesses need to do their work. Warehouse and self storage are driven by something simpler: how many people live nearby and how much stuff they buy. That changes the analysis from a business question to a population question — and that distinction changes almost everything about how you evaluate the opportunity.

The break-even rent calculation at the end of this post is where that distinction becomes concrete.

Warehouse distribution is not one product type either

Just like industrial overall, warehouse distribution is further subdivided.
And the differences between the subtypes matter — they determine what kind of building you need to build and what kind of tenant you're building for.

Regional warehouse

Think of a regional warehouse as the last major hub before something gets loaded onto a truck and sent to your doorstep.

These buildings run up to about 100,000 square feet, with ceiling heights of 18 to 24 feet — lower than some of the bigger types, but enough for standard racking systems. The office component is higher than you might expect — up to 20% — because there's a real operations team managing inbound shipments, outbound dispatch, invoicing, and coordination.

Loading dock ratio is one dock for every 5,000 to 15,000 square feet, which is more moderate than the heavy distribution facilities. Refrigerated space can go up to 5% if the tenant needs cold storage for part of their inventory.

Bulk warehouse

Bulk warehouse is a step further down the supply chain.

This is where goods arrive in large volumes — off a container ship, out of a truck that came from a port — and get staged until distribution can move them out. The Dole banana operation at the Port of San Diego's 10th Street marine terminal is a good example: the ship arrives, containers offload, they move into a massive staging warehouse until trucks can pick them up and distribute them inland.

These buildings are bigger: 100,000 to 1,000,000 square feet. Ceiling heights of 20 to 36 feet, because stacking containers or high-cube pallets requires more vertical clearance. Office stays below 10%. Dock ratio: one dock for every 5,000 to 10,000 square feet.

Heavy distribution

Heavy distribution is where Amazon-scale logistics live.

Over 100,000 square feet, often much larger. Office below 5% — almost nobody works in an office here; the facility is a machine. Ceiling height above 24 feet, with the best heavy distribution facilities pushing well beyond that. And loading dock ratios drop to one per 5,000 square feet or less — because the whole facility is oriented around trucks pulling in and out continuously. No cooler space, because nothing being handled here requires cold storage.

The dock count per square foot on these buildings looks almost excessive until you understand the velocity. Amazon fulfillment centers don't store inventory in the traditional sense — they're more like sorting machines. Stuff comes in, gets allocated, and goes out, ideally within hours. Every dock is a throughput constraint, so more docks equals more throughput capacity.

Refrigerated distribution

Refrigerated distribution is where the rules change.

Once cooler or freezer space exceeds 25% of the building, you're essentially building a giant refrigerator. That means insulated concrete slabs on the floor, insulated walls and roof, specialized mechanical systems, and construction costs that are meaningfully higher than a standard warehouse.

Ceiling height minimums are around 20 feet. Dock ratio: one per 7,000 to 10,000 square feet — more moderate, because loading time matters more when temperature integrity is at stake. These buildings are highly specialized for specific users: food processors, pharmaceutical distributors, cold chain logistics.

Rack-supported warehouse

Rack-supported warehouses are the outliers in the industrial category.

Ceiling heights of 60 feet or more — I've seen buildings over 100 feet on a single level. Inside, the racking structure itself is part of the building's structural system. Cranes run back and forth in the aisles, moving pallets of material around with a precision that's closer to manufacturing than traditional storage.

Office below 5%, dock ratio below one per 5,000 square feet, no cooler space. These are built for a specific operational system that requires specific tenant commitment — they're not something you build speculatively and hope someone fits in. The tenant's automation and racking system and the building are essentially one integrated facility.

Why warehouse demand is a population math problem

What ties all five subtypes together is something the other industrial categories don't have: a clear link to population growth and retail consumption.

Flex-tech and manufacturing demand comes from business conditions — R&D spending, manufacturing contracts, business formation rates. Warehouse demand is simpler. If population grows, people buy more things. If people buy more things, those things have to move through a supply chain. That supply chain runs through industrial buildings.

That's why the demand analysis for warehouse space looks so different from office or flex-tech analysis. You're not asking "is the job market growing?" You're asking "what is the population in the trade area, how fast is it growing, and how does that translate into retail and wholesale sales volume?"

When those numbers are strong — fast-growing trade area, rising incomes, active e-commerce penetration — warehouse demand follows. That's also why the Amazon Tijuana distribution center makes sense. The Tijuana-San Diego metro region is one of the largest cross-border population concentrations in North America. The warehouse is where the population is, even if the population is technically on the other side of an international boundary.

For developers forecasting absorption in this space, the advice is to be careful about single large transactions. Warehouse buildings are big and don't turn over frequently. One tenant signing a lease for 400,000 square feet can look like a market on fire. One tenant vacating can look like a collapse. The better indicator is to track wholesale and retail sales trends over time, map population growth by trade area, and look at the underlying consumption data rather than just real estate transactions.

Self storage: the industrial asset that goes where nobody else will

Self storage is unusual in the industrial category for two reasons.

First, it's the only type that chases residential, not commercial activity. Every other industrial type locates near suppliers, customers, ports, or universities. Self storage locates near neighborhoods — specifically, growing neighborhoods with enough households to generate regular demand.

Second, it's the only type that uses gross rent instead of triple net. Operators collect a flat fee from tenants, handle all operating costs themselves, and manage a large number of very small, very short-term leases. The management intensity is high relative to other industrial types, but so is the revenue per square foot.

The demand drivers are almost entirely residential. Population growth, household formation, household turnover — when families move, they need somewhere to put things during the transition. Small businesses use self storage for record retention and overflow inventory. And in markets like Southern California, RV and boat storage can generate higher revenue per square foot than the storage units themselves, because demand for covered vehicle storage outstrips supply almost everywhere.

Site selection for self storage

The site criteria are fairly specific.

• Growing neighborhoods with household density
• Middle-class or higher income levels — the ability and willingness to pay monthly storage fees
• Preferably limited nearby competition — though that's increasingly difficult to find in built-out markets
• Site size: 2.5 to 5 acres, enough for the building footprint plus required setbacks and emergency vehicle circulation
• Location on or near a major arterial street — you want visibility and easy access
• Zoning already in place — self storage doesn't do well through discretionary approval; neighbors rarely welcome it enthusiastically

That last point matters more than it might seem. Getting self storage approved through a planning commission hearing is difficult. Getting it permitted where zoning already allows it is a much more predictable path. Most self storage developers won't pursue a site unless the zoning is already favorable.

One thing worth holding onto from this material: in Southern California, developers sometimes make more money from the RV and boat storage portion of a self storage site than from the storage building itself. That's counterintuitive — it sounds like a parking lot — but covered vehicle storage in a market with limited land and strong recreational vehicle ownership is a real unmet need. Worth modeling carefully if the site has the acreage for it.

The break-even rent: the honest number

After working through all five industrial types — and before evaluating any specific project — there's a calculation that puts everything in its proper context.

It's called the break-even rent.

The question it answers is simple: what is the absolute minimum rent I need to charge, per square foot per month, just to service my debt and cover my operating costs? Not to profit — just to not lose money.

Here's how it works, using a generic industrial example:

What this number tells you is the floor.

If the market is charging $1.50 per square foot per month for comparable space, and your break-even is $2.68, the deal doesn't work. Not at that cost to build, not at that financing rate, not with those operating expenses. Something in the model has to change before this project makes sense.

That's the honest test. And it's the test that can get rushed in the excitement of a promising site.

What happens when you change the assumptions

The break-even calculation's real value comes from stress-testing it.

Changing the building cost from $350 to $400 per square foot adds $5 million to the total project cost, which changes the financing cost, the minimum NOI, and ultimately the required rent. That one input change might push your break-even rent up by $0.20 to $0.30 per square foot per month — enough to take a deal from marginal to non-viable in a competitive market.

Changing the financing rate from 6% to 7% adds $350,000 in annual financing cost, which flows through to the minimum NOI and the required rent. In a rising rate environment, deals that worked at one rate may not work at another — which is one of the reasons development activity slows when rates rise.

The DSCR — debt service coverage ratio — is the buffer a lender requires above the minimum. At 1.2x, the project needs to generate 20% more income than debt service alone. At 1.25x, that buffer increases. Lenders set this based on how risky they think the project is. The developer's job is to build a pro forma where the income supports that coverage at realistic rents.

What I find most useful about this calculation is that it turns vague optimism into a specific number. You can't say "I think the market will support this rent" without also knowing whether that rent covers your actual costs. The break-even rent forces that honesty.

And that's really what a pro forma is supposed to do. Not prove a deal works — prove whether the assumptions you're making are internally consistent and whether they hold up against what the market will actually pay.

A few things I'm taking away

• Warehouse distribution is actually five subtypes — regional, bulk, heavy, refrigerated, and rack-supported — each designed for a different point in the supply chain with materially different building specs
• Demand for warehouse space is driven by population and retail consumption, not by office market conditions or business formation rates — the trade area analysis looks more like retail feasibility than commercial real estate analysis
• Amazon's willingness to build across an international border is a useful illustration of the population bet logic: the building goes where the people are, not where the address is cleanest
• Self storage is the only industrial type that actively chases residential growth; every other type chases commercial activity
• RV and boat storage in Southern California markets can generate more revenue per square foot than the storage units themselves — worth modeling carefully when the site has the acreage
• Self storage almost always needs zoning in place before you pursue it; discretionary approval is genuinely hard to get
• The break-even rent is the floor — not a target — and it changes materially when any major assumption shifts
• The pro forma's job is not to prove a deal works; it's to force honesty about whether the assumptions are internally consistent and whether the market will actually support the required rent
• Changing the building cost by $50 per square foot, the financing rate by 1%, or the DSCR by 0.05 can move the break-even rent enough to kill a deal that looked marginal — which is why iteration on the pro forma is not optional

The part that reframed how I think about this: break-even rent is not a pessimistic calculation. It's a precision tool. It takes four inputs that could all be wrong — building cost, financing rate, coverage requirement, operating expenses — and produces a number that can be directly compared to what the market is actually charging. That comparison is the honest answer to whether a project makes sense to pursue.

It's not a guarantee. But it's a real test. And real tests, applied early, are the thing that separates feasibility from wishful thinking.

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, senior housing, and the first half of industrial real estate.