Ecca collection

Perhaps it is more of a turtle than a tortoise, since Yuzhny is the city’s second port and the building is perched on the edge of the Black Sea, at the eastern tip of Europe. But whichever mimetic form you settle on, the roof is the most dominant element of the building, and one that provides an inexpensive but durable and distinctive covering.

What it is covering is a range of facilities, but most important is the multi-purpose sports hall at the centre, which can be adapted for the performance of as many sports as possible, and can seat up to 2,000 spectators.

The roof that curves over it, and also shoots off in subsidiary arches, seemingly in all directions, has a total area of 6,000m². It is made from prepainted aluminium, and created with standing seams. This is a tried and tested roofing technique, but one of which there is not much sophisticated experience in Ukraine. Although standing-seam roofs are constructed fairly regularly, they are made from sheets of steel, not from coil, and the standing seams are formed by hand, using basic tools. The result is that residual stresses are introduced to the metal, and therefore it is not perfectly flat.

In addition, coatings are often applied without an adequate primer, leading to flaking and rusting within a few years.

In contrast, for the sports hall there was an ambition to have a high-quality durable building – echoing the life span of the tortoise which is typically 100 years. Hence the architect specified the precoated aluminium coil.

In addition, the project uses a new finish. Seryogin wanted a metallic azure blue colour, the colour of a blue sky on a beautiful day, and selected a PVDF (Polyvinylidene Fluoride) coating. This is not only flexible enough to cope with the curvature and the formation process; it is also translucent which means that the colour changes with the external lighting conditions. Like the sky above it, it is never quite the same colour.

These effects were emphasised by the use of a new finishing technique which creates a honeycomb texture within the surface. It has an advantage over other texturing approaches in that, unlike embossing, it does not involve any damage to the surface and so there is no reduction in durability. It uses a new approach known as ‘vault structuring’ in which the surface coating is built up in a manner that mimics the way that structures are created in nature, naturally forming this three-dimensional textured surface.

This surface increases the interest of the appearance, as the different angles reflect the light in a range of directions. It also, thanks to its three-dimensional nature, enhances the stiffness of the metal. A trapezoidal structure supports the roof, with the space between filled with Foamglas insulation.

So this building is actually using biomimicry at two scales – at a macro scale in the shape of the roof, and at a micro scale in the way that the coating is built up. This tortoise should certainly outlast and outlive any hare – and anyway, who wants a sports building in the shape of a hare?