Polyurethane Foam — Polyurethane foam is applied to the interior surface of the Airform. Entrance into the air-structure is made through a double door airlock which keeps the air-pressure inside at a constant level. Approximately three inches of foam is applied. The foam is also the base for attaching the steel reinforcing rebar.

Polyurethane Foam — Polyurethane foam is applied to the interior surface of the Airform. Entrance into the air-structure is made through a double door airlock which keeps the air-pressure inside at a constant level. Approximately three inches of foam is applied. The foam is also the base for attaching the steel reinforcing rebar. <cite class='credit'>(David South Jr)</cite>