Westminster reported 3,582,581 rentable square feet of industrial and flex space at a 2.4 percent vacancy rate in September 2023, and that is the pressure sitting under every warehouse shell schedule on the Front Range. When vacancy is that low, a building that delivers late loses its tenant, and a shell that delivers without the right utility stubs loses months to the tenant's improvements. The shell has to be done on time and done in a way that makes the next phase easy.
A warehouse shell is the structure, envelope and base building systems, built to a defined point so an occupant can complete the interior. That typically means foundations and slab, structural frame or tilt panels, roof, exterior walls, dock doors and equipment, sprinkler rough-in, site utilities, paving and a defined level of power and lighting. The scope line decides how much the tenant has to build, and drawing it carefully is the first project decision.
We build shells for developers who are leasing to unknown tenants and for owner-operators who need a base building they can fit out themselves. The two cases push in different directions, and we handle both with the same goal: no surprises when the tenant moves in.
Demand, vacancy and what tenants ask for
Industrial users along the Front Range are asking for clear height, trailer parking, dock doors and electrical capacity that suit their own operations, and each of those is a design variable the shell has to settle early. In Westminster, 30 business parks and over 18.7 million square feet of commercial space are reported in the city's 2024 economic profile. Smaller markets are building too: three new industrial buildings at 4431 and 4611 Brantner Road in Evans, built in 2025 near Highways 85 and 34 and I-25, offered a 7,500 square foot first suite for lease or sale.
That range from a 7,500 square foot suite to a million-square-foot park shows how wide the shell market is. A small-bay flex shell needs demising walls, individual utilities and unit-by-unit access. A big-box distribution shell needs deep truck courts, long dock walls and large-capacity fire water. The type of tenant determines the shell, and we help owners decide what to build before the drawings are final. Land near the E-470 interchange at Exit 22 in Aurora, which serves the roughly 4,000-acre Aurora Highlands development, shows how new corridors open for this kind of building.
Where the shell stops and the tenant starts
We define the shell with a responsibility matrix that lists each system and who provides it. The matrix covers floor slab thickness and flatness, structural capacity for racking, clear height, roof loading, dock door count and spacing, electrical service size, gas, water, sanitary and fire protection. Items such as office build-out, racking, mezzanines and process utilities are typically left for the tenant. The line should be unambiguous, because disputes about it are costly.
The structural system is selected to fit the program. Many large shells use tilt-wall, which we cover under tilt-wall industrial buildings, while smaller or more flexible buildings may use pre-engineered metal buildings or a conventional steel frame. The choice depends on span, height, loads, schedule and the exterior character the owner wants.
A shell schedule built backward from the lease date
If a lease date is tied to delivery, we work backward from it. Foundations and slab come first, followed by the frame, roof and enclosure. The sequence is straightforward, but the critical path runs through procurement and permitting more often than through construction. Sprinkler design, electrical gear and dock equipment can all have longer lead times than the structure, and we release them during design.
Weather windows matter. Concrete placement and roofing are most efficient in moderate conditions, and cold or wet spells slow both. We plan the slab and roof to avoid the harshest periods when we can, and we price winter protection when we cannot. The goal is a dry building with a finished slab, so tenant trades can start immediately.
Decisions that affect the next tenant
A few shell decisions have outsize effects. Clear height, column spacing and slab flatness limit the types of racking and equipment a future tenant can use. Power service size and fire protection design determine the commodity classes a tenant can store. Truck court depth and dock count govern the traffic the building can handle. We walk owners through those options during preconstruction and show what each costs.
Local permitting also shapes the shell. Cities and counties adopt different code editions, and the review for a shell can be a separate permit from the tenant improvement permit. We plan the permit path with the owner, including how to handle future tenant changes. For a typical warehouse product, we establish the submittals early.
Keeping quality high while the pace is fast
Shell construction rewards repetition. The same details, the same crews and the same sequence on building after building produce speed and consistency. We keep a field team that stays with the project, and we use checklists at each handoff: after foundation, after slab, after frame, after roof. Each checklist includes the items that matter to the future tenant, such as slab flatness readings and roof testing.
Quality control is built into the process, not added at the end. We take slab flatness measurements, test roof membranes and verify dock door operation. We also document utilities with as-built records so tenants and their designers know where lines are. A developer building several shells in a park benefits from the repeatability and from the lessons we carry from building to building. For tenants who need the next step, our work on industrial tenant improvements continues from the same base, and for logistics users, see logistics and distribution.
Define the shell scope before drawings are final
Send us your site, program and target delivery date and we will return a scope matrix, a schedule and a budget range. Contact Industrial Contractors of Colorado to start.
Common Questions
What is the difference between a cold shell and a warm shell?
A cold shell typically stops at the structure, envelope and basic utilities, leaving heating, lighting and interior finishes to the tenant. A warm shell adds items like heating, lighting and basic electrical, so the tenant can occupy sooner. The exact line should be written into a responsibility matrix.
How long does a warehouse shell take?
Duration depends on size, structure and weather, and a large tilt-wall building and a small metal building are very different. Permitting and equipment lead times often control the start of construction. We build a schedule from the lease date backward and show what has to be released and when.
Should we build speculative or build-to-suit?
A speculative shell carries lease risk but can capture demand quickly, while a build-to-suit shell reduces risk and customizes to the user. We can build either. We help owners choose by pricing the features that add flexibility, such as higher clear heights and extra dock positions, against their cost.
What utilities should a shell include?
At a minimum, water, sanitary, fire service, electric and gas service to the building, sized for the likely tenant. Oversizing costs less at the start than adding capacity later. We discuss service sizes with the utilities before design is final.
How do you handle changes after the permit?
Through change control. We document the change, price it, check code implications and update drawings. Changes that touch structure, fire protection or egress need approval from the building department.