Using techniques, materials and know how largely developed in Italy, the Canadian contracting firm of Casey-Hasten Limited, has set up a special division for the development and application of inflated concrete domes. The first step in the 4 phase process is a special anchor assembly is cast into a concrete ring foundation of the required diameter. A semi-circular key is formed into the top of the ring foundation by means of a double chamber inflated tube, which is removed after the concrete has set. The second phase is the inflation preparation. Build/Tek has developed its own three-ply neoprene and rubber inflation membrane reinforced with elastic fiber. Thickness of the membrane is in the range of one-eighth to three-sixteenth of an inch and the core consists of a fabric providing two-way stretch. An anchor tube on the outer edge of the membrane is inserted into the foundation key and inflated. A net work of steel springs in a carefully designed three layer configuration is then placed over the membrane and anchored to the foundation ring. Smooth reinforcing bars are inserted into the springs and fastened at one end to the anchor assembly. The final stage of inflation preparation is the installation of a screeding bulkhead on top to the foundation wall and the placement of screeding blocks on the membrane itself. The third phase is the concrete placement, inflation, and curing. Two mix formulations are employed- one of 7 inch slump for the center of the dome and one of 3 and one-half inch for the peripheral concrete. The mixes, which consisted of 3000 psi concrete with one-half of an inch stone, incorporated various plastericizers, fly ash and a 4 hour retarder. Placement was handled in the main by means of a concrete pump and a special concrete placing boom. After strike off the concrete is covered with a light weight stretchable membrane, which is also fastened to the foundation ring. Air is supplied by specially designed blowers is then introduced through ducts in the foundation wall and the entire assembly slowly rises until the full height is reached at the center. The final phase is finishing. When the done is self-supporting, the blowers are shut down and the center plug is removed, releasing and directing the air between the concrete and the membrane, making it possible to remove the latter. After the removal of the top membrane, complete sections of the dome, up to 30 percent of the diameter at the base, may be cut away to provide doorways, glazed curtain walls or ordinary windows.