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Everywhere N.C. Zoo visitors look, they will see rocks. Rocks are one of the most dominant features, especially when used as confinement walls within animal exhibit areas. They look real and as though they’ve always been there. But most of the rocks within the exhibits are man-made; they are a complex creation of wire mesh, steel armature, concrete and skilled sculpting.
The zoo’s Design department staff members study actual rocks, photographs and sketches to duplicate their models so that they are as true to natural formations as possible – even down to the lichens, mosses, cracks and the weathering process.
Before any rock construction begins, designs are worked out on paper and often in models. The rocks must not only appear real, but also must fit the overall habitat design. The next step, fabrication, begins with a steel frame structure, usually constructed by welding the frame pieces together. This structure defines the shape and supports the concrete covering. A metal mesh or lath is then attached to the framing to hold the concrete.
Concrete is usually applied by high-pressure hoses that blow the concrete onto the form. This initial concrete covering averages about four inches thick, depending on what animal is being contained. Lizards require less, polar bears, considerably more. The surface must then be finished by hand. Using masonry trowels and brushes, design artists either brush the concrete for a smooth finish or carve it to simulate cracks and folds. For detail work, the concrete must be applied, at times, by hand.
Painting, the final step, is done with a special mix of concrete, dry pigments and a liquid binder. Large areas are sprayed with several basic colors or splattered with paint thrown from a distance. Different lichen shapes can be achieved this way. Splattering can also be done by flicking paint from a gloved hand. Large lichen patches and details are painted by hand.Besides their use as exhibit retaining walls, these man-made rocks also serve as means of concealment for elements that are visually undesirable in a natural setting. Rocks and rock-like walls can hide barns, feeder bowls, doors, fences and moats.
These man-made rocks, along with artificial logs and stumps, are not only functional, but also are aesthetic elements that add to the visual effectiveness of the exhibits.
Article by Tom Gillespie
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N.C. Zoo is a member institution of AZA and an agency of the N.C. Department of Environment and Natural Resources, William G. Ross Jr. Secretary; Michael F. Easley, Governor. A part of the North Carolina Government portal.
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