Our shelters are constructed of panels welded together and anchored to an above-average concrete slab. Each wall panel is made using 4" steel channel welded into a rectangular unit with a #4 rebar system welded inside. High strength concrete is then added and cured for 30 days prior to installation. We also weld lifting eyes to the wall panels in order to lift them, load them and erect/weld them together. The roof panels are made in like manner but are made from a higher strength 4" channel system that includes a #5 rebar system welded inside. The entire unit can be anchored to your slab using either steel plates embedded into your concrete slab or by installing 2"x 2" angles welded to our wall panels and then drilled and anchored into your slab. The shelters weigh about 600 pounds per lineal foot.