Why Commercial Projects Fail During Lease-Up (And How to Avoid It)

Commercial development is a two-act problem. The first act is construction: permits, budgets, contractors, draws, inspections. Most investors spend months getting this right. The second act is lease-up: finding tenants, negotiating leases, building out spaces, and actually getting to stabilized income. Most investors underestimate it.

The projects that fail rarely fail because the building cost more than expected. They fail because the building sat empty — or leased up far slower than the model projected — and the carry costs during that period eroded the returns or broke the deal entirely.

This article covers the six most common lease-up failure modes, what to watch for in underwriting, and how to build a model that accounts for reality instead of optimism. If you're new to commercial development underwriting, start with the ground-up development analysis guide for the fundamentals.

Failure Mode 1: Building What the Market Won't Absorb

The most dangerous lease-up failure starts before a shovel hits the ground. Demand mismatch — building a product type that the local market can't support — is invisible until you're staring at a vacancy rate that doesn't budge.

The scenarios that show up most often:

• Flex space in an oversupplied submarket. You build 10,000 SF of contractor bays. There are already 40,000 SF of similar product sitting vacant nearby. Rents are soft and falling, not rising.
• Retail in a trade area without foot traffic or density. The space looks right on a map, but the rooftop count and traffic counts don't support the rents you projected for service retail or food-and-beverage tenants.
• Storefront product with no parking. Small commercial tenants need specific site conditions. A coffee shop without adequate parking won't take your space at market rent, or won't take it at all.
• Industrial or storage in a market with no trade demand. Contractor bays and flex industrial depend on a density of tradespeople and small businesses that isn't present in every market.

For specific asset types like self-storage and flex, see the deep-dive analysis guides: how to analyze a flex space investment and how to analyze a self-storage development.

Failure Mode 2: No Tenant Pipeline at Certificate of Occupancy

This is the most common mistake made by first-time commercial developers and smaller operators building their first flex or retail project.

The sequence usually looks like this: construction takes 12–18 months. The owner focuses entirely on the build. A CO lands. Then they start making calls and posting listings. Three months later, they have a few tours but no signed leases. Six months later, there might be one LOI. Meanwhile, debt service has been running since construction closed.

The correct approach is to work backwards from your target CO date and start tenant outreach 6–12 months before the building is done. For smaller projects with 4–8 units, you want signed LOIs or letters of intent from serious prospects before you're handing out keys. For larger projects, lenders often require a pre-leasing threshold before they'll fund construction at all.

Pre-leasing is its own topic with real nuance — what counts as "pre-leased," what lenders actually require, and when it makes sense to build spec vs. wait for a commitment. That will be covered in depth in the pre-leasing strategy guide.

Failure Mode 3: Over-Improving and Narrowing Your Tenant Pool

This failure mode is subtle and often expensive. It happens when a landlord — or a developer trying to attract a specific anchor tenant — builds out the space to a level of specialization that makes it hard to lease to anyone else.

The canonical example is a full commercial kitchen. You install a Type I hood, grease trap, hood suppression, walk-in cooler, and stainless prep surfaces because you're targeting a restaurant. The restaurant deal falls apart at the last minute. Now every non-food tenant who tours the space either doesn't need the kitchen or is actively put off by it. Your tenant pool just shrank significantly.

Other examples:

• Brewery-grade infrastructure. Trench drains, CO2 systems, 3-phase 400A service, specialized ventilation. Ideal for a brewery. Limits appeal to most office, retail, and light service tenants.
• Specialized plumbing for a salon or spa. Multiple shampoo bowls, pedicure stations, or treatment room plumbing. If that tenant doesn't sign or leaves, you now have an awkward mid-suite plumbing layout that most replacement tenants don't want.
• Daycare-specific modifications. Oversized restrooms, outdoor playground infrastructure, non-standard egress. These improvements support the original use well, but they limit the pool of replacement tenants at lease end.

The full breakdown of high-customization tenants, what their buildouts mean for future re-leasing, and how to structure leases to protect yourself when they leave is covered in detail in the vanilla shell vs. tenant improvements guide.

Failure Mode 4: Under-Improving and Killing Your Rent

The opposite problem is also common — delivering a space so unfinished that you can't attract tenants at the rent you need, or can only attract tenants who want a steep discount to compensate for the buildout they have to fund themselves.

A cold dark shell — four walls, a roof, utilities stubbed in but nothing finished — is appropriate for some users: large industrial tenants with their own construction teams, manufacturing operations with specialized requirements, or tenants who specifically want to build to their own specs. It is not appropriate for retail, service businesses, or most flex tenants.

The economics of under-improvement are counterintuitive. A landlord who delivers a cold shell might save $20–35 per SF in finish costs. But that tenant will likely demand:

• A significant rent reduction to reflect their buildout cost
• A longer free rent period (3–6 months instead of 1–2)
• Or simply walks away to a competing space that is already finished

The math often works out worse than if the landlord had finished the space and charged market rent. Modeling both scenarios in DealForge before you decide on delivery condition is worth the hour.

Failure Mode 5: Tenant Improvement Mistakes

For most commercial leases, the landlord and tenant negotiate who pays for what improvements, and under what conditions. Getting this wrong is one of the most expensive mistakes in commercial real estate — it can cost the landlord tens of thousands of dollars upfront, or cost them tenants who walk away because the deal economics don't work.

The common TI mistakes:

The structure of a TI allowance — how to cap it, what a work letter covers, what happens when the tenant leaves, and how to underwrite TI as a capital cost rather than an expense — is covered in full in the vanilla shell vs. tenant improvements guide.

Failure Mode 6: Rent Assumptions That Never Held Up

The most common error in commercial development underwriting is modeling rent as if it starts on the day the building opens, at full contract rate, with no concessions.

Reality is different. Commercial leases typically include:

• A free rent period. 1–3 months for smaller spaces and shorter leases. 3–6 months or more for longer-term or larger leases. During free rent, the tenant is in the space and operating — but paying nothing. Your debt service is still running.
• A lease-up timeline. Even in a strong market, it takes time to sign leases. A 6-bay flex building rarely leases all 6 units in the same month. Model a realistic schedule — maybe 1–2 units per month.
• Rent that reflects actual conditions. If the market is soft, your pro forma asking rent may be above where deals are actually getting done. Check comparable signed leases, not just asking rents.

The difference between those two columns is the difference between a deal that works and a deal that requires an emergency capital call or defaults.

How to Underwrite Lease-Up Correctly

A properly underwritten commercial development model accounts for three things most pro formas skip:

1. A Lease-Up Reserve (Separate from Construction Contingency)

This is cash set aside to cover debt service and operating costs during the period between CO and stabilized occupancy. The appropriate size depends on your market, product type, and pre-leasing situation — but a common starting point is 6–12 months of debt service on top of the construction budget.

2. A TI Reserve (Separate from Tenant Improvement Allowance)

Even if you plan to deliver vanilla shell, you will likely need to contribute TI to land tenants at market rent. That TI is a capital cost that reduces your effective return. Budget it explicitly. BuildGrade can help estimate buildout costs by space type and region before you commit to a TI allowance in a lease negotiation.

3. A Staggered Revenue Model

Instead of modeling rent as a flat number from day one, model it as a ramp. DealForge's development module lets you input a lease-up timeline and model best-case, base-case, and worst-case scenarios — so you can stress test whether the deal survives a slow lease-up before you commit to the project.

If the deal breaks in the slow case, it is not a well-underwritten deal — it is a bet on the best case. Know the difference before you commit.

The Toolkit: From Market Validation to Underwriting

Lease-up risk lives across three stages of the investment process, and different tools address each stage:

These questions are not independent. A market with strong absorption (OppMap) means you can underwrite a faster lease-up in DealForge. A space that requires significant TI (BuildGrade estimate) means your effective yield is lower than the sticker cap rate suggests. Modeling them together is what separates institutional underwriting from optimistic projections on a napkin.

What Good Lease-Up Underwriting Looks Like

A properly underwritten commercial development or lease-up deal has answers to all of the following before capital is committed:

• What is the current vacancy rate for this product type in this submarket? Is absorption positive or negative?
• Who are the target tenants, and are any of them already in conversation? Is there a signed LOI before breaking ground?
• What condition will the space be delivered in, and what TI allowance is appropriate to land tenants at target rent?
• What does the lease-up timeline look like in a base case and a slow case? Does the deal survive the slow case?
• Is there a reserve for lease-up carry costs, separate from the construction contingency and the TI budget?

If any of those questions are unanswered, the model has a gap. The projects that fail during lease-up are almost always the ones where one of those gaps got papered over with optimism.