Abstract: A building has a support structure fabricated by anchoring light weight, hollow, vertical steel posts into a pre-poured foundation, and then strengthening the posts by filling the hollow cavities with concrete. The structure provides the framework around which straw bales are stacked to produce insulated wall cores for the building. The posts, which are sized to support the ceilings and roof trusses, are square in cross section and are positioned on a foundation so that the faces of the posts form 45 degree angles with the edges of the foundation slab. The center of the end faces of those straw bales that are in contact with a post are triangularly notched so that the corner of the post mates with the notch, allowing the longitudinal edge face of the bale to lie along the direction of the slab edge. Posts are not located at the corners of the building, but are spaced at least a bale's length away from a corner.