With many Greater Boston municipalities grappling with rent destabilization and a lack of housing diversity, what can result when housing development is viewed as a long-term investment? How about the concept of “solids,” coined by Frank Bijdendijk, a former housing czar in the Netherlands? The concept continues the structure-infill ideas outlined by another Dutch architect, John Habraken, in his 1961 book Supports: An Alternative to Mass Housing.

Solids are flexible and durable buildings that allow an investor to model economic viability over a long period. In contrast to selling fast and building cheap, a durable building is constructed with materials and details that age well and thus accrue value over time. Plus, a flexible building can accommodate changes in lifestyles or even uses, yielding profits over multiple generations.

Such a building — think of the Roman basilica type or industrial-era warehouses — requires higher initial investments than is currently normal, which can be offset if operating costs are low and by separating permanent or collective elements from temporary or individual ones. The initial investor of a solid building constructs the “base” elements (load-bearing structure, access and circulation, roof and exterior façade, common services and amenities), and the “fit-out” (partitions, finishes, fixtures, and so forth) is determined and paid for by another investor: the inhabitant.

The division between permanent and temporary elements results in a housing typology unlike today’s developments. One example is Solid 11 in Amsterdam (2010), designed by Tony Fretton Architects for the Dutch housing commission. The client required that its main building components have a 200-year life span, with a floor plan that could change according to user needs. More recently, our market building in Brussels features a double-height structure that can be filled internally with mezzanines or expanded vertically with additional floors.

The conventional building template consists of “towers” — rooms, units, or offices built of steel or wood-frame structures — above a concrete “podium” for parking, storage, cultural amenities, and commercial retail. The tower and podium are efficiently organized for particular uses, with every space programmed and compressed to maximize rentable or resale square footage. Ceilings are low, walls abundant, and windows correspond precisely to interior arrangements. In the future, it will make more sense to demolish and rebuild these buildings rather than adapt and reuse.

Solids, on the other hand, are not towers built on podiums but sustainable “shells” with generous floor-to-ceiling heights, open floor plans, long structural spans, high load-bearing capacity, and large mechanical and circulation areas. The spatial quality of solids is akin to the industrial warehouse that has successfully morphed into mixed housing. Unlike older buildings, solids are not a finite resource; they marry a durable, flexible building type with a development model that is economically feasible in the short and long term.

Imagine housing that provides a stable residence for precarious millennial or immigrant workers within open floor plans, movable partitions, common services, and shared resources; or multifamily units that adapt to changing tastes, growing families, or an aging population. Could light, “clean” industries, maker spaces, or live-work arrangements exist alongside, above, or below? Municipalities should invest in “base” buildings as long-term public assets that help resolve affordable-housing shortages today and — who knows? — can segue into an alternative use that meets a future need.

Kyle Nelson is an illustrator and art director at Stoltze Design.