04/26/2023
Strengthen Your Home | Take Emergency Action • Tornadoes
Why do they matter?
Tornado safe rooms constructed following FEMA guidance or ICC 500-certified storm shelters are your best chance for survival when deadly hurricanes and tornadoes strike. They provide near-absolute life safety protection and can withstand extreme winds, even up to EF-4 or EF-5 level tornadoes.
Saving lives is the first and foremost purpose of safe rooms and shelters, but they can also make your home more valuable. According to FEMA analysis, a safe room can increase your home’s selling price by approximately 3.5%. As site-built and prefabricated safe rooms can cost as little as $3,000, tornado safe rooms and shelters are both lifesaving and moneywise.
What do I need to know?
There are six different types of tornado safe rooms and shelters.
Cast-in-Place Concrete
These rooms are built with removable forms and assembled onsite. Once the forms are placed, the rebar is set inside the formwork, then filled with concrete. The panels are removed after the concrete hardens.
The walls and ceilings are formed at once to create a strong, secure structure. When you add this type of shelter to an existing home, it is usually added to the exterior. The panels can be fitted with liners to create concrete exterior surfaces that look like siding, brick, or stone.
This room can be built virtually anywhere in a new house.
Insulating Concrete Forms (ICFs)
These rooms are created using foam blocks that contain steel reinforcement, fitted together, and then filled with concrete. The foam is a permanent part of the room and provides insulation to the building.
The ceiling is constructed with ICFs creating a continuous, steel-reinforced concrete structure. The forms can be used in new or existing construction.
Interior and exterior finish options include drywall, sheetrock, or siding nailed to the foam.
You can use ICFs to build a stand-alone safe room or an entire house.
Concrete Masonry
Concrete masonry safe rooms are common in new construction and can be built in one to two days. Individual concrete blocks are set in place; rebar is placed for strength and durability, and the cells are fully grouted.
Reinforcement comes out of the foundation, centered in grouted cells, and is carried to the top. Two rows of steel at the top of the wall hold the assembly together.
Bathrooms, walk-in closets, and basement storage rooms commonly serve as locations for these safe rooms in new construction. Exterior applications are often in a garage, detached garage, or storage building. This method offers a variety of texture and finish options.
Precast Concrete
This room is formed off-site and delivered to a house for installation. It can be used virtually anywhere in a new house. It is usually added to the exterior when added to an existing home.
The room is anchored using steel angles (L brackets) and bolts. Precast concrete can be used to build an entire house, and it can be finished in a variety of colors and textures using form liners. Exterior surfaces can be customized to look like siding, brick, or stone.
Prefabricated Steel
Prefabricated safe rooms must meet the ICC 500 standard and are available in smaller sizes than the safe rooms constructed using FEMA P-320. These rooms typically cost less than site-built safe rooms.
Installation costs for prefabricated safe rooms vary depending on the delivery distance as well as any necessary foundation or geotechnical work required to ensure installation on a sturdy foundation.
Prefabricated safe rooms can be ordered online or in-store at home improvement retailers.
Wood Frame and Steel Sheathing
The wood frame construction method uses wood framing covered by steel sheets and two layers of plywood. Hurricane ties are used to connect the roof to the studs, and another hurricane tie is added at the bottom with an anchor bolt to hold everything down. This type of safe room can be built in less than one day.
This room can be used as an addition to an existing home after verifying that the foundation is adequate. It can also be included in new construction in a variety of room options, such as a closet, storage space, or stand-alone garage structure.
Sheetrock, textures, and paint can be used to customize finishes and room colors. A wood frame safe room is most affordable when constructed as part of a new home, as the cost of additional materials is primarily the door assembly, steel, and extra plywood.
Where do I start?
Whether you build a safe room onsite or install a prefabricated shelter, consider the safety of its location. Safe rooms are designed to protect you and your family from extreme winds but cannot protect you from flooding. That is why they should never be built or placed in areas expected to flood during hurricanes, thunderstorms, or other severe weather events.
Contact your local building official, emergency management office, or floodplain management bureau to determine if your home is in a storm surge zone, high flood risk zone, or flood-prone area.
More Resources
Tornado-Strong.org – Checklists, fact sheets, and video library
FEMA P-361: Safe Rooms for Tornadoes and Hurricanes: Guidance for Community and Residential Safe Rooms
FEMA P-320: Taking Shelter from the Storm: Building or Installing a Safe Room for Your Home
ICC 500: Standard for the Design and Construction of Storm Shelters
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