Abstract: A space frame of double-layer flat grid type, in which the upper grid is skewed or angularly displaced by 45.degree. relative to the lower grid, has pairs of oblique struts (16) connecting the lower grid nodes (14) to the upper grid nodes (15). At a lower grid node (14) where two chords (10, 11) are superimposed, one pair of oblique struts (16) in a vertical plane through one chord (10) has a common terminal (17) between the two chords (10 and 11). A bolt (22) through the terminals (17) and the chords (10 and 11) secures the parts together. At the nodes (15) of the upper grid, the terminals (19) of the struts (16) are interposed between the superimposed upper grid chords (12 and 13) and secured by bolts (21).