/All Commercial Videos Petrogonia. Roof slate 940 Views Petrogonia. Roof slate Commercial Video Client Petrogonia Date September, 2012 Date 1 September 2012 Director Apostolos Chouliaras Share: You may also like this House with Bioclimatic Design Elements – Volos / All Commercial Videos, Commercial Videos Low Energy Consumption Building Agria-Volos / All Commercial Videos An innovative way to stop and utilize the underground fresh water inflow in foundation of buildings / All Commercial Videos