Rather than placing concrete into forms, however, a fresh concrete mix is sprayed onto wall panels that have been erected in the shape of the building. A nozzleman applies concrete from a pressurized hose to encompass the reinforcement and build up the wall thickness, forming structural shapes that include walls, floors, roofs, and other assemblies.
Any surface suitable for accepting fresh concrete can be used: wood, steel, brick, and polystyrene are common. Finishes are often applied directly to the concrete while it is still wet.
Shotcrete have advantages similar to all other concrete walls. They are strong, durable, resistant to disasters, fires, mold, insects and vermin, and have low permeability, good thermal mass, and create tight envelopes. Although the hardened properties of Shotcrete are similar to conventional cast-in-place concrete, the nature of the placement process provides additional benefits, such as very fast erection, particularly on complex forms or shapes, including curved walls and arches.