If you need cost certainty, push for a turnkey or vanilla box delivery and tie rent start to written acceptance criteria. If you want design control and are prepared to manage construction risk, a shell delivery with a negotiated tenant improvement allowance fits better. Either way, document scope, finish specifications, and measurable completion milestones in the lease before you sign.
TL;DR:
- Shell labels vary and carry no legal weight, so leases should specify included systems, finishes, capacities, fixture counts, and measurable acceptance standards.
- Choose turnkey delivery when cost certainty matters; choose a tenant improvement allowance for design control, but budget separately for specialty systems, permits, and overruns.
- Compare full term costs, including rent during construction, design and permit fees, operating expenses, and lost revenue in a 60 day delay scenario.
- Medical tenants should verify medical gas, exhaust, isolation room HVAC capacity, and sterilization plumbing, then start leasing 12 to 18 months before opening.
Table of Contents
- Precise Lease Definitions: Shell, Cold Shell, Warm Shell, and Vanilla Box
- Who Pays: Turnkey Delivery vs TI Allowance vs Tenant-Funded Work
- Comparing Total Occupancy Cost and Time to Opening
- The One Negotiation Checklist and Work-Letter Essentials to Use Before You Sign
- How We Advise Medical and Office Clients on Shell vs Vanilla Box
- Our Take: Stop Comparing Delivery Conditions on Finish Level Alone
- How We Help You Negotiate Delivery and TI Terms
- FAQ
- Sources
Precise Lease Definitions: Shell, Cold Shell, Warm Shell, and Vanilla Box
A core-and-shell space (often called a cold shell) gives you the building’s structure, exterior walls, and roof, but little else. Base building mechanical, electrical, and plumbing systems may stop at the property line, and the interior is unfinished concrete or slab with no interior walls, ceilings, or HVAC distribution.
A vanilla box (sometimes called white box or warm shell) moves further along: it typically includes finished demising walls, a finished ceiling grid, HVAC distribution to the space, basic electrical and lighting, restrooms built to code, and painted walls ready for a tenant’s final finishes.
The labels shift by market and by broker, which is exactly the problem.
- Cold shell: structure and exterior only, no interior HVAC distribution or finished walls.
- Warm shell: structure plus base building MEP stubbed to the space, sometimes with a rough HVAC system in place.
- Vanilla box: warm shell plus finished walls, ceiling, lighting, and restrooms, ready for a tenant’s trade fixtures.
None of these terms carry legal weight on their own. A lease that simply says “delivered as warm shell” without listing capacities, fixture counts, and finish specifications invites disputes at turnover.
Who Pays: Turnkey Delivery vs TI Allowance vs Tenant-Funded Work
Three economic models cover most deals, and each shifts cost and control differently. Under turnkey delivery, the landlord manages and pays for the build-out to an agreed specification, which gives the landlord more construction responsibility and the tenant more cost certainty. Under a tenant improvement (TI) allowance, the landlord contributes a set dollar amount per square foot and the tenant manages the buildout, taking on design control but also the risk of costs above the allowance. Under tenant-funded work, the tenant pays for everything beyond the base shell, usually in exchange for a lower rent or a longer free-rent period.
An allowance typically covers standard construction items: framing, drywall, flooring, ceiling tile, standard lighting, and basic HVAC distribution. It commonly excludes furniture, specialty MEP (medical gas, lab exhaust, commercial kitchen hoods), owner-required upgrades to base building systems, and permit or impact fees. Our tenant-improvement allowance playbook walks through sizing these numbers before you negotiate.
Term length and rent concessions are tied directly to these decisions. A longer lease term typically supports a larger allowance or a full turnkey build, since the landlord recovers the cost over more months of rent. A shorter term usually means a smaller allowance, more tenant-funded work, or a lower upfront landlord investment.
- Turnkey favors tenants who want predictable costs and a faster path to opening.
- TI allowances favor tenants with specific design or specialty needs who are comfortable managing a contractor.
- Tenant-funded work usually appears in shorter-term deals or spaces with heavy rent concessions.
Delivery condition is a negotiated term, not a fixed market standard. Turnkey, allowance, and tenant-funded work are the three principal paths, and each one shifts cost and control in a different direction, so the right choice depends on how much construction risk you want to hold.
Comparing Total Occupancy Cost and Time to Opening
Advertised rent rarely tells the full story. Total occupancy cost adds base rent, TI out-of-pocket beyond any allowance, downtime and soft costs during construction, and operating cost differences driven by the systems you inherit.
Specialty uses change this math fast. Medical tenants dealing with medical gas routing, exam-room exhaust, isolation-room HVAC capacity, or sterilization plumbing often find that a second-generation space with existing specialty infrastructure reduces upfront cost compared with a first-generation shell that needs those systems built from scratch. Industrial tenants face a similar calculation around loading docks, clear height, and power capacity.
A short worksheet keeps the comparison honest:
- List base rent and any escalations for the full term.
- Estimate TI out-of-pocket beyond the landlord’s allowance or turnkey scope.
- Add soft costs: design fees, permit fees, and rent paid during construction before you open.
- Estimate downtime, lost revenue, or temporary location costs while the space is built out.
- Compare operating costs across options, including HVAC efficiency and shared-system charges.
Pro Tip: Model two or three rent-commencement scenarios (early completion, on-schedule, and a 60-day delay) so you know your downside before you sign, not after.
The One Negotiation Checklist and Work-Letter Essentials to Use Before You Sign
A single checklist, applied consistently, prevents most delivery disputes.
- Require measurable acceptance criteria: finish schedules, HVAC commissioning reports, MEP capacities, electrical panel amperage, and plumbing fixture counts, not just “delivered as shell.”
- Address ADA path-of-travel obligations explicitly, since alterations to a commercial facility can trigger new-construction or path-of-travel requirements depending on scope, and the lease should state who pays for that work.
- Tie rent commencement to a documented inspection and commissioning sign-off rather than a calendar date, since construction managers confirm work matches scope, meets code, and that lien releases have been received before a project closes out.
- Define who pays for code upgrades triggered by your use, and who controls common-area interference during construction, since common-area modification costs often fall to the landlord unless the lease permits pass-throughs.
- Use a tenant leasing checklist early to capture occupancy density, parking impact, and fixture needs before the work letter is drafted.
- Confirm fire door and egress hardware meet code before occupancy, an item often missed in buildout punch lists but critical for final inspection sign-off.
Pro Tip: Bring your construction manager into lease review before you sign, not after, so acceptance criteria match what can actually be inspected and verified on site.
Before finalizing terms, pull a lease abstract to confirm every obligation lines up with what was negotiated, and check an estoppel certificate if you are stepping into an existing building to verify prior alterations and current conditions.
How We Advise Medical and Office Clients on Shell vs Vanilla Box
We recommend medical tenants start the leasing process well in advance of the target opening date, allowing enough time to coordinate TI design, specialty infrastructure testing, and permit approvals without rushing acceptance criteria. Our medical office leasing guidance covers that timeline in detail.
For office repositioning, we generally favor turnkey delivery when an owner wants to control finish quality and add energy-efficiency clauses across multiple suites, and we favor an allowance when a single tenant has unusual layout needs. In practice, we help clients size TI budgets, draft lease language that captures measurable acceptance criteria, and coordinate directly with construction managers so nothing gets lost between the work letter and the job site.
Our Take: Stop Comparing Delivery Conditions on Finish Level Alone
Most advice on shell versus vanilla box focuses on what is physically included at delivery. That framing misses the bigger issue: the real decision is about who holds construction risk and how that risk gets priced into rent, allowance size, and timeline.
A vanilla box with vague acceptance language can cost you more than a shell with a tightly written work letter, because disputes over what counts as “finished” eat months of rent-free occupancy you never planned for. We think the first priority should always be measurable, inspectable criteria tied to rent commencement, not the label on the delivery condition. Chase the acceptance criteria first, and the shell-versus-vanilla-box question becomes a budgeting exercise instead of a legal risk.
— Jim
How We Help You Negotiate Delivery and TI Terms
We work through this exact decision with medical and office tenants and landlords regularly, and we know where delivery disputes usually start.
- Tenant and landlord representation to negotiate scope, allowance size, and acceptance criteria before you sign.
- TI budgeting support so your out-of-pocket estimate matches what the work letter actually covers.
- Lease review and abstraction to confirm commissioning, lien release, and rent-commencement language protects you.
If you are weighing shell against vanilla box for a medical or office space, reach out through our services page and we will walk through your specific deal before you commit to terms.
FAQ
What is the difference between a cold shell and a warm shell?
A cold shell includes only the structure and exterior, with no interior HVAC distribution or finished walls. A warm shell adds base building mechanical systems stubbed to the space, sometimes with rough HVAC in place, but still lacks finished walls, ceilings, and fixtures.
What does vanilla box mean in a commercial lease?
A vanilla box, also called a white box, is a space finished with demising walls, a ceiling grid, basic lighting, HVAC distribution, and code-compliant restrooms, ready for a tenant to add trade fixtures and final finishes. It sits a step beyond a warm shell in terms of completion.
Who pays for tenant improvements in a shell space?
Payment depends on the negotiated structure: turnkey delivery means the landlord pays and manages construction, a TI allowance means the landlord contributes a set amount while the tenant manages the rest, and tenant-funded work means the tenant covers costs beyond the base shell. Term length and rent concessions typically determine which model applies.
How long does it take to build out a shell space compared to a vanilla box?
A shell space generally takes longer to reach occupancy-ready condition because it requires full interior construction, including walls, ceilings, and HVAC distribution, while a vanilla box needs only final finishes and fixtures. The exact timeline depends on permit review, specialty infrastructure needs, and contractor availability.
What should a medical tenant check before accepting a shell or vanilla box space?
Medical tenants should verify medical gas routing, exam-room exhaust capacity, isolation-room HVAC, and sterilization plumbing before signing, since these items often determine whether a space should be delivered turnkey or with a larger allowance. Starting the lease process 12 to 18 months ahead gives time to test these systems and coordinate approvals.
Sources
- BOMA releases green lease guide (FacilitiesNet excerpt)
- Documenting common areas in office leases (BOMA)
- Types of real estate managers and their responsibilities (IREM excerpt)
- 2010 ADA Standards for Accessible Design (ADA)