Demolition has long been the default answer to an ageing building. A structure that no longer serves its original purpose, the reasoning goes, is an obstacle to be cleared so that something better can replace it. Yet a quiet reversal is under way in many cities, where old factories become apartments, disused railway stations become galleries, and warehouses become offices. Advocates of this adaptive reuse make an environmental case first: a building already standing contains a great deal of embodied energy, the energy spent on making its bricks, steel and concrete, and demolishing it wastes that investment while constructing a replacement spends more.
The argument is not only ecological. Old buildings often occupy prime locations and carry a texture, in their proportions and materials, that new construction struggles to imitate. Critics respond that conversion can cost more than building afresh, and that historic structures rarely meet modern standards for insulation and accessibility without expensive alteration. There is force in these objections. But they tend to compare the cost of conversion with the cost of a new building alone, ignoring what the new building destroys. A fairer accounting would set the full price of demolition and lost character against the price of adaptation, and in many cases the result would be much closer than the critics assume.