supply all kind of prefab house,chicken house,school house, steel hangar, steel garage, steel shed,steel shelter, steel barn ... all kinds of steel structures, steel bulding, metal building, modular house, steel frame for warehouse, workshop, garage etc, steel beams, other ... -span,single floor,double floors!3.base:cement and steel foundation bolts4.column and beam:material Q345(S355JR)or Q235(S235JR ...