Construction starts with a giant inflatable fabric form called an Airform, anchored to the foundation and inflated into the dome's final shape — no scaffolding required to hold it up. From the inside, workers spray a layer of polyurethane foam onto the Airform, which becomes the dome's insulation. Steel rebar is then attached in an engineered pattern of horizontal and vertical bars, and finally, a special sprayable concrete called shotcrete is applied over the rebar. Once it sets, the Airform, foam, steel, and concrete have become one solid, continuous shell — which is where the 'monolithic' name comes from.