The Natural History Museum, London

Location: Natural History Museum’s Darwin Centre, London UK

Architect: Anna Maria Indrio, C.F. Møller

Polished Plaster Signature Range Armuralia

Natural White

A Monumental Cocoon: A New Architectural Icon

A new architectural icon for the capital, this extraordinary design features a vast, free-standing structure within a glass atrium, taking the form of a monumental cocoon—breathtaking in its originality and creative brilliance. The groundbreaking eight-story-high Darwin Cocoon houses a unique collection of 17 million insects and 3 million plants, gathered over the last 300 years by renowned scientists including Charles Darwin, Alfred Russel Wallace, and Sir Hans Sloane. This awe-inspiring building completes the Museum’s life science complex, the Darwin Centre, following the completion of the first phase in 2002.

Natural Elegance and Innovation

The response of the architectural design team at C.F. Møller, led by partner Anna Maria Indrio, was to create an engaging form inspired by the organic elegance of nature. The surface and texture needed to embody this essence, and so the subtle sheen of ivory-colored Armuralia was selected. The Polished Plaster’s delicate surface, with its intersecting network of ‘silk threads’ criss-crossing the cocoon, offers both movement and a visual framework for the structure’s openings and niches.

Armourcoat was specified to deliver a unique solution that combined both insulation and the final decorative layer. The cocoon performs a crucial protective role, providing thermal mass to regulate internal temperature fluctuations—vital for preserving the museum’s precious specimens. In addition, the structure houses cutting-edge laboratories for 250 international scientists and features an interactive exhibition for visitors.

Unique design and technical solutions

A groundbreaking skeletal structure, measuring sixty-five meters long, was built by sprayed concrete specialists Shotcrete—marking the first above-ground sprayed concrete structural element in the world. Expanded metal mesh was attached to the steel re-bar framework, and a 250mm thick layer of concrete was spray-applied, resulting in a 3,500 m² raw concrete surface. Armourcoat then applied a resin-modified render to minimize localized surface variations before fitting a layer of polystyrene insulation. Using Dryvit Genesis adhesive and over 16,000 Hilti insulation fasteners, a 50mm polystyrene layer was added to the entire surface, followed by a layer of reinforcing mesh set into the Dryvit Genesis basecoat.

To craft the distinctive silk threads that wrap the structure, a custom-cutting machine was developed, allowing for precise slots to be cut into the individual 340 panels that comprise the cocoon surface. A total of 5.6 km of edge bead was then fitted, and Armourcoat’s Anticrack substrate preparation system was applied. Anticrack, a polymer- and fiber-modified gypsum skim-coat plaster, created a first-class substrate, ensuring the Polished Plaster remained in optimal condition. Two layers of keycoat were applied before the final finish.

The cocoon’s striking silk-like effect was achieved using Armuralia Polished Plaster, an exquisite, smooth finish with subtle tonal variations.

This monumental achievement is not only a unique design and technical solution befitting the Natural History Museum’s significance, but also serves as a stunning example of the cutting-edge commercial projects undertaken by Armourcoat, a company that celebrated twenty-five years of creative excellence in 2009.