A little corner to share thoughts on steel building
If you prefer not to pour a full floor, then pour piers, or square pads, where you intend to place your support columns. The pads should be of sufficient size to contain the anchor bolts needed to hold the support columns in place. The next step is to erect the support columns in the anchor bolts that you placed in the foundation. You then raise and fasten the rafters to the tops of the support columns and attach your roof purlins and wall girts to the rafters and support columns. (The purlins and girts will hold your wall and roof sheeting in place.