His style belongs to the Belgian Expressionist movement. Ost focused on the daily life of the Flemish working class and the animals that assisted them. In works like Boerenwagen met twee paarden ervoor and Man in amazonezit op een trekpaard, he used thick, energetic lines to capture the weight and power of draught horses. He avoided the academic polish of his contemporaries. Instead, he chose a raw, graphic method that emphasised the physical presence of his subjects.

Modern collectors value the honesty in his depictions of ordinary moments. Prints of works such as Wasdag or Vrouw met hoed en een kers in haar mond offer a direct connection to early 20th-century Belgian life. His compositions have a graphic quality that fits well in contemporary interiors. The focus on rural traditions and human resilience provides a grounded aesthetic for any wall.