Retrofitted storm shelter construction involves building a new, free-standing room within an existing room. Often times certain window-less rooms located near the center of the building such as: bathrooms, walk-in storage closets, walk-in pantries, or extra space in the garage can serve more than one purpose and be modified as a secure safe room. This method makes more efficient use of existing space, but will generally result in a small loss of floor, interior wall, and ceiling height space. In many of today’s homes and businesses this slight loss of space will hardly be noticed or missed.
This new freestanding safe room will be structurally separate from the surrounding house or building and not be attached to any existing walls or ceiling – it will only be anchored to an adequately poured concrete floor so that even if the surrounding building is destroyed to the foundation, the storm shelter will remain intact - thus offering "Near Absolute Protection" to the occupants. This method involves modifying and making all changes necessary to strengthen an existing room or area of a home or office so that it will provide the required resistance to wind forces, and windborne debris impact according to FEMA 320 (Federal Emergency Management Agency).
New additions generally cost slightly more than retrofitting, but if space is tight from the onset, a new addition will give you the flexibility of adding additional square footage for possibly a new bathroom or walk-in closest that is specifically built as a safe room. When undertaking the adventure of altering your existing home or office to construct a safe room, it is often a great time to build just a little more additional space for other living needs as well – a new den, larger kitchen etc. If zoning permits, a garage addition, or carport will also be an ideal location for a safe room.
A stand alone storm shelter can also be built most anywhere on your property that your local building department zoning ordinances or community covenants allows. Stand alone shelters require that you, your family, or your employees exit your home or workplace to reach the shelter, and for this reason it is recommended that the shelter be built at a safe distance.
Often times on stand alone additions, the shelter is designed with a short hallway between it and the main structure. This hallway is designed to break away should the rest of the building be destroyed by a storm. This offers additional protection for the occupants moving into the shelter.