A construction system having structural members with pre-manufactured rows of holes for fastening. A first kind of structural member (33, 35 and 35a in fig. 2) has a row of holes equally spaced at a distance N. A second kind of structural member for diagonal bracing (43 in fig. 2) has a row of holes equally spaced at a distance equal to the length of the hypotenuse of a right triangle with the other two sides having a length of N or a multiple of N. A third kind of structural member (24 in fig. 2) has two rows of holes equally spaced at a distance N, with the holes of one row perpendicularly intersecting the holes of the other row. Large diameter fasteners (60 in fig. 8), with a cross-hole for a crossing fastener, allow mounting two or more structural members at the same longitudinal disposition to perpendicular sides of a structural member of the third kind.