A construction method for building a post frame building by first constructing the roof near ground level. The roof assembly can have a removeable safety net system and be coupled to a plurality of support members, such as columns having a hinge connection to the roof assembly. Upon the roof system being lifted, the hinged columns can fold under the roof system and then be coupled to one or more anchor points established in the ground. The roof system can be raised into position at a pre-determined height using a lifting apparatus, such as a hydraulic lift.