Facing bricks manufactured by extruding a mixture of clays and water. After drying off the water added for the extrusion, the bricks are fired in an oxidizing art mosphere in a Tunnel Kiln. Each model is burned at its own optimal firing temperature (always >1000º C).

Due to the carbonate content in their base clay, the suction (initial rate of water absorption) of these products is greater than 0.10 gr/cm 2 minute. To avoid having to wet the bricks before they are laid (a necessary, although not always applied, measure with suction of over 0.10 gr/cm2 minute), they are there forewaterproofed by immersion or soaking with a silicon compound after leaving the kiln and before being packed. This treatment improves their layability, facilitates cleaning and keeps wall assemblies attractive and free from contamination over a long period of time.