Breathing Space does not follow the conventional structure of an academic book as it dispenses with both an introduction and a conclusion. Instead, readers enter the book directly through a first chapter on chimneys, somewhat from above—like Santa Claus coming down a chimney. In the first chapter, they explore analogies between tracheas and flues, as well as the role of chimneys as pneumatic technologies designed to ventilate space. Once inside the book, the third chapter turns to breathing walls and opens with an experiment by the German hygienist Max von Pettenkofer. In the late 1850s, he locked himself in his Munich office and sealed every crack and crevice to test the permeability of architecture’s seemingly solid elements—floors, ceilings and walls.

Despite these efforts, the fire in his stove continued to burn vigorously, an indication for a constant influx of air from outside. Fires, after all, thrive on oxygen. Pettenkofer concluded that the brick walls of his office must be porous, even though most of his contemporaries likely assumed that walls were airtight. Years later, in a series of published lectures, he included an illustration to corroborate this observation. In it, a figure with inflated cheeks blows air into a glass funnel, one of which is fixed with an airtight seal on either side of a cylindrical piece of brick coated in melted wax.

At the opposite end, a candle flickers on the verge of being extinguished, demonstrating the brick’s porosity. Through experiments like this, he argued that walls have pores, much like our skin or an eggshell. Residents in the nineteenth century lived in leaky houses, which were considered advantageous because they maintained a constant connection to the outside air. This exchange helped counteract indoor air pollution produced by human breathing. Of course, this is a far cry from today’s high-tech building envelopes, which enclose us behind airtight facades, often in the name of energy efficiency or comfort. At its core, Breathing Space asks what kinds of buildings we want to inhabit as consciously breathing beings: permeable structures embedded in the atmosphere, or sealed containers that close us off from the environment.