In 1889, Franz Wiesner took over his father’s business and began acquiring land for expansion. In 1896, he purchased additional land for a dedicated carpentry yard, where timber for barns and roof structures could be hewn and prepared before being taken to the construction site for assembly.

With the construction of its first machine-equipped workshop, Franz Wiesner expanded into architectural joinery. A building materials warehouse followed, providing the foundation for the company’s construction business. In 1911, he invested in the first mechanical saw. Three more sawmills followed, supplying the company with sawn timber until 1986.

WIEHAG’s innovative approach to timber construction was already evident early in the company’s history. In 1928, the carpentry business used Friedrich Zollinger’s patented system to build its own self-supporting sawmill hall. The impressive structure remained in place until 1950.

A Zollinger roof is a self-supporting roof system made from identical prefabricated timber elements. Arranged in a diamond pattern, the individual elements form a lattice shell structure.