Flex and Light Industrial Construction in Boulder County

Dock doors on one wall, glass and offices on the other, and a clear bay between them: that is the flex building, and the reason it keeps getting built is that tenants change faster than structures do. A research instrument company needs lab benches this year and assembly lines next year. A service business wants showroom, offices and a truck bay. The building has to handle all of it without a rebuild.

Flex space in the Boulder Valley is shaped by two forces that do not exist in a generic industrial market: a city that keeps many of its industrial districts industrial and wants employment space, and an energy code that pushes mechanical design in a specific direction. We build the shell and core with enough clear height, floor strength and utility capacity to accommodate that range, and we build the first tenant fit-out when the owner wants it delivered as one package.

Where flex buildings sit in this market

The business parks in east Boulder are the model most owners picture. Flatiron Park is a master-planned park of about 200 acres, with roughly 2.3 million rentable square feet and more than 100 companies, according to a 2017 report on a portfolio sale. That figure is dated, so owners should treat it as a sense of scale rather than a current count. In 2022 the city adopted the East Boulder Subcommunity Plan, which guides the area over two decades as an employment center, keeps many industrial areas industrial, and adds mixed-use neighborhoods in selected locations.

For a developer, those two points set expectations: zoning that protects industrial use makes sites scarce, and the plan signals where mixed-use pressure will occur. Our job is to read the plan alongside the specific parcel and tell the owner whether a flex building, a tilt-wall box or a mixed building is realistic. Neighboring east Boulder business areas show the range.

Tenants the building must serve

Flex tenants fall into four groups: light assembly and fabrication, research and development with some lab, service and trade businesses that need showroom and yard, and distribution users with small volumes. The building's structure should work for all four, which means 20 to 28 feet of clear height where the site and height limits allow, a slab that takes forklifts, and electrical service that can be added to without trenching the whole lot.

Office content is higher than in a warehouse, often a third or more of the plan. For that reason owners sometimes weigh a flex building against a conventional office building with a back-of-house warehouse, and we price each so the comparison is straightforward. Where tilt-wall is the best structural system we describe it in tilt-wall construction.

Core, shell and the first fit-out

A typical flex package includes site work, foundations, the slab, the structure and enclosure, storefront glazing at the front, dock-high and grade-level doors at the rear, roof, and base-building mechanical, electrical and fire protection. Mechanical systems are sized for the shell and left stubbed for tenant loads, because a lab user and an office user need different air handling.

The first tenant improvement often follows within weeks. We schedule it as a second phase so the owner can lease the building while the shell is going up and the tenant's needs are still being defined. Our work on that stage is described in tenant improvements, and the dock and yard concrete is covered in truck courts and dock aprons.

Price points that matter

Costs vary by clear height, the share of finished office, the mechanical approach and the amount of site concrete. Because the city's energy code requires all-electric systems in most new commercial buildings and a margin above ASHRAE 90.1-2022, the mechanical package tends to be a larger share of the budget than in older industrial buildings in the region. Roof insulation and window performance also reflect the code.

Speculative owners ask us where to hold back. The usual answer is to build the shell and core at a good level and leave interior finishes, tenant mechanical zones and special electrical for the tenant. Over-building a flex shell for an imagined tenant is costly, and under-building it limits the market. We show owners a good, better, best comparison with the effect on leasing speed and rent noted in plain terms.

Gunbarrel, Niwot and the State Highway 119 corridor

Gunbarrel is an unincorporated area of about 9,554 residents with flooding as its principal natural hazard, and some of its parcels are zoned general industrial. Reports from 2016 described sales of buildings and vacant parcels there, but ownership and availability from that period are likely out of date, so we help owners verify the current status of any Gunbarrel site before they plan around it.

Niwot sits on State Highway 119 about halfway between Boulder and Longmont and is another place where flex space fits, with direct highway access along the corridor. Floodplain review, drainage and a plan for the Highway 119 improvements underway nearby are the first items we check on any site there. For owners who manage buildings for tenants, property management firms get the same checklist.

How we hold the building flexible

The discipline is to design for the second tenant, not the first. We ask early how the building would be divided if two users took half each, where the demising walls would go, how the utilities would be metered, and whether the dock count and parking ratios allow it. These questions are inexpensive to answer on paper and costly to answer after the slab is poured.

We also build with an eye to maintenance: reachable rooftop equipment, protected roof drains, and pavement that sheds water away from the building. Sites near creeks or ditches get an extra review of grading and overflow routes. The owner receives a close-out set with the demising and utility logic written down, so a future tenant improvement does not begin from guesswork.

Tell us about the tenants you expect

Bring the parcel, the target tenant mix and your leasing timeline. We will return a shell and core price, an optional first fit-out, and a plain note on what the city and county reviews will require.

Questions Owners Ask

What clear height should a flex building have?

Most flex tenants are comfortable between 20 and 28 feet. Height limits, the fire code and the roof system all affect the answer, and in Boulder the 35 foot zoning cap in many districts is a hard boundary unless site review allows more. We test the number against the specific parcel.

Can you deliver the shell and the first tenant fit-out as one contract?

Yes, and many owners prefer it. We schedule the tenant work as a second phase so the lease-up can proceed during shell construction, and we price it separately so the owner sees each component.

Is Flatiron Park still the model for new flex space?

It is a useful reference for scale, but the figures we have are from a 2017 report and may have changed. Current availability and zoning for any parcel should be confirmed with the city and a broker before planning.

How does the all-electric requirement affect a flex building?

It pushes the mechanical design toward heat pumps and electric service sized for the full load. New all-electric commercial buildings in the city must beat ASHRAE 90.1-2022 by 10 percent. We bring the energy modeler into the first design meeting to avoid redesign.

What are the main permitting hurdles in unincorporated areas?

Floodplain review, drainage and the county building code amendments, which adopt the 2021 International Building Code with local changes. We ask the county for the edition and any soils report requirements before pricing.

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