Abstract: A method and apparatus for converting a post-style poultry house to a clear span style poultry house. The apparatus includes a truss assembly including a center truss section adapted to be mounted to the roof beams and first and second outer truss sections adapted to be secured to the center truss section. The trusses are installed without the removal of the roof and without removal of the drinker and feeder equipment of the existing post-style poultry house. In installing the trusses, first the center sections of the trusses are attached to the roof beams and then the upper ends of the outer sections are attached to the center sections. Then the lower ends of the outer sections of the trusses are secured to the poultry house footers. Once the truss sections are all secured to each other and secured to the footers, the posts are cut away and removed.