All Valley Storm Shelters above ground Safe Rooms have a 1/4” steel floor. There are two main reasons for the floor. The first reason is to protect occupants from electrocution. If the shelter is struck by lightning or a high powered electrical line falls on the shelter, you cannot become part of the ground or circuit with a floor. Secondly the floor is part of the structural integrity of the shelter. During our demo of direct hit (see video on video testing page), the pressure from the impact of the car hitting the shelter was absorbed by all anchors. Without the structural support of the floor, the anchors on the side that was hit could have failed.