Standing in her 2018 Serpentine Gallery Pavilion on the green of­­­ London’s Kensington Gardens, Mexican architect Frida Escobedo recalls the start of the project just six months ago: she received an email with the subject line “Invitation” and assumed it was an offer to join the gallery’s mailing list. “After the shock faded,” she laughs, “we began working through many iterations to find something that hadn’t been done before.”

Seventeen other pavilions have occupied the gallery’s lawn, by architects such as Zaha Hadid and Frank Gehry. At 38, Escobedo is the youngest yet, and her appointment reflects an ambition in recent years to showcase “architects of global promise, rather than global prominence,” notes gallery CEO Yana Peel.

All architects get the same brief: the temporary structure should cover at least 3230 square feet, accommodate a café, and host diverse events. Another implied condition: the buildings will have a second life elsewhere.

For Escobedo, “resolving the contradiction” of a building that will exist in a specific location for four months, and then at an unknown location for an uncertain duration, allowed her to draw on her own preoccupations: the capacity of buildings to register the passage of time, and the idea, drawn from philosopher Henri Bergson, that duration shapes perception of ourselves and our environments.

A rectangular enclosure, with entrances at opposite corners, the pavilion sits parallel with the gallery’s eastern facade, to underscore its site-specificity. This form is intersected by a second rectangle, implied by a staggered array of cross walls, a trapezoidal pool and the roof canopy, which is rotated to align with due north, making a conceptual link to the Prime Meridian.

The pavilion’s “dual nature” is developed further in its construction. Its rough screens are inspired by the breeze walls found in Mexican residential architecture, but built from a custom-made version of the cement roof tile common to ordinary British houses, and threaded onto vertical steel poles. “We wanted to use something modular, industrially-produced, and not too heavy, which would age and weather well,” says Escobedo. “Roof tiles made perfect sense.”

While some of this embodied thinking will only be apparent from the posted explanatory notices, every visitor will experience the spatial and visual complexity that Escobedo has conjured from simple means. External walls shift between opacity and semi-transparency depending on the angle of approach. Inside, the small building is almost maze-like, and the figures of people passing between partitions dissolve into indistinct blobs of color, before reappearing in distorted reflection on the curved canopy overhead.

Between the tiles, the steelwork skeleton already beginning to rust, a nod to the pavilion’s afterlife. “A building is never finished,” says Escobedo. “Architecture is a process, which continues until the object is a ruin.” While some predecessor pavilions seemed to be the summary of a life’s work, this beguiling structure feels like the start of a journey, for both the architect and her building.