Adaptive reuse, converting an existing building originally constructed for one purpose to a different use, has become one of the more active development strategies in several of Innergy Integral’s markets. The elevated office vacancy that followed the pandemic’s effect on office demand, combined with persistent housing supply constraints, has created a policy and market environment that is more favorable to office-to-residential conversion than at any prior point in the past several decades.
The appeal is real: existing buildings have established addresses, existing structural systems, existing utility connections, and in many cases existing parking that would cost substantially more to build from scratch. The constraints are equally real, and they are the reason that adaptive reuse projects are harder to execute well than new construction, even when the economics look favorable at first glance.
The Office-to-Residential Conversion Opportunity
Office buildings that are candidates for residential conversion share several characteristics: they are typically located in urban or suburban cores where residential demand is strong, they have structural systems that can accommodate residential floor plans, and they have reached a vacancy level that makes their current office use economically marginal.
The buildings that convert most successfully to residential are those with floor plates that are compatible with residential planning. Narrow floor plates, 60 to 80 feet wide, allow natural light to reach interior units from windows on both sides of the building, producing residential units that feel like apartments rather than like interior rooms in a large office building. Wide floor plates, 100 feet or more, create deep interior spaces that cannot be served by windows and that require complex ventilation solutions for interior units, adding cost and reducing the quality of the residential product.
In Seattle, the elevated office vacancy in the urban core has created office-to-residential conversion opportunities that the city’s housing shortage makes economically interesting. In Denver, the LoDo and Midtown corridors have older office buildings with narrower floor plates that are more conversion-friendly than the 1980s and 1990s office stock with large floor plates. In Dallas and Houston, the regulatory flexibility of both cities’ development environments has enabled conversions that would be harder to permit in markets with more prescriptive design review.
The Construction Challenges Unique to Adaptive Reuse
Adaptive reuse projects are consistently more expensive per square foot than the construction cost of equivalent new construction, a fact that surprises developers who assume that not having to build the structure reduces cost. The structural system savings are real but are typically more than offset by the cost of adapting the existing building’s systems and configuration to the new use.
Existing MEP systems are almost always obsolete. Office buildings from the 1970s, 1980s, and 1990s have HVAC systems designed for open-plan office use, large air handlers that distribute conditioned air through ceiling plenums to open floor plates. Converting to residential requires either replacing those systems entirely with individual unit HVAC or making major modifications to the existing systems to accommodate unit-by-unit conditioning control. Either approach is expensive, and the cost is typically not visible in early-stage conversion feasibility studies that look at the structural system cost but not the MEP replacement cost.
Floor-to-floor heights drive residential compatibility. Residential buildings typically have floor-to-floor heights of 9 to 10 feet. Many older office buildings have floor-to-floor heights of 11 to 14 feet, which sounds like a benefit but can complicate MEP coordination in the ceiling plenum and affects the relationship between windows and residential floor plans. Some high-floor-to-floor office buildings can accommodate two residential stories within one existing structural bay through mezzanine insertion, but this approach adds significant structural and construction complexity.
Existing condition discoveries. Adaptive reuse projects consistently encounter existing conditions that were not visible in the pre-purchase due diligence, asbestos-containing materials in floor tile adhesive or ceiling texture from pre-1980 construction, lead paint in painted surfaces, structural systems that do not meet current seismic requirements, and electrical systems that cannot be upgraded to residential load requirements without replacement. Each of these conditions adds cost that was not in the initial feasibility budget.
The standard contingency for adaptive reuse projects, 15% to 20% of estimated construction cost, is not excessive given the frequency with which existing condition discoveries affect construction budgets.
Entitlement for Conversion Projects
Adaptive reuse projects face entitlement considerations that new construction on vacant sites does not. In most markets, converting a building from commercial to residential use requires a change of use permit, which triggers review under the current building code for the new use. A 1970s office building that complied with the code when it was built may not comply with current code when reviewed for residential conversion, requiring accessibility upgrades, fire protection improvements, egress modifications, and energy code compliance measures that add both cost and permit complexity.
Some cities have adopted streamlined conversion programs that reduce the regulatory burden for office-to-residential conversion as a matter of housing policy. Seattle, Denver, and some Texas cities have adopted or are considering expedited review processes for conversion projects that demonstrate housing creation in areas where housing is needed. Developers pursuing conversion projects in these markets should investigate the applicable programs before assuming that the standard change-of-use process applies.
Historic preservation requirements apply to conversion projects in buildings with historic designation, adding design constraints on what modifications can be made to the building’s exterior and, in some cases, to its interior. The cost premium for historic-compliant construction in designated buildings is real and must be reflected in the feasibility analysis.
Innergy Integral provides development advisory and construction management for adaptive reuse projects, drawing on direct experience with historic renovation and conversion construction across our service area.
Innergy Integral provides these services in Seattle, WA and across our six-state footprint.
Related: Commercial Development Services · Construction Management Services · Multifamily Development Services · Development Advisory Guide
Markets: Commercial Development Seattle WA · Multifamily Development Denver CO · Commercial Development Dallas TX