Use the filters below to find answers to frequently asked questions about Building Science guidance regarding:
If you need additional information, please email the FEMA Building Science Helpline or call at 866-927-2104.
Please visit the Building Science Resource Library to reference all hazard-specific publications and guidance documents.
For a hurricane community safe room, the number of spaces for standing or seated, wheelchair-bound, or bedridden people should be determined based on the expected occupancy of the safe room as calculated by the designer and the applicable authority having jurisdiction. As a minimum, each community safe room should be sized to accommodate at least one wheelchair space for every 200 occupants.
It is also important to note that community safe rooms should provide equal access for all persons in accordance with all federal, state, and local Americans with Disabilities Act (ADA) requirements and ordinances. Table 2 shows the minimum safe room floor area per occupant for hurricane community safe rooms. The minimum usable floor area per safe room occupant is larger for a hurricane community safe room than for a tornado community safe room because occupants require a longer sheltering time for hurricanes.
| Hurricane Community Safe Room Occupant | Minimum Usable Floor Area* per Safe Room Occupant |
|---|---|
| Standing or Seated | 20 square feet |
| Using a Wheelchair | 20 square feet |
| Relocated to a Bed or a Stretcher | 40 square feet |
*See FEMA P-361 for more information on usable safe room floor area.
Yes. FEMA provides guidance on the location of residential safe rooms in relation to flood hazards.
Per FEMA P-361, flood hazards should be considered when designing a residential safe room. Flood loads acting on a structure containing a safe room are strongly influenced by the structure’s location relative to the flood source. Tornado or hurricane residential safe rooms should be located outside of the following high-risk flood hazard areas:
More information on these siting restrictions and additional elevation requirements can be found in the Flood Hazard Siting and Elevation Criteria for Residential Safe Rooms (fact sheet) and FEMA P-361.
Yes. FEMA provides guidance on the location of community safe rooms in relation to flood hazards. Per FEMA P-361, flood hazards should be considered when designing a community safe room. Flood loads acting on a structure containing a safe room are strongly influenced by the structure’s location relative to the flood source. Community safe rooms should be located outside of the following high-risk flood hazard areas:
Exceptions can be made to these restrictions in some instances; for more information and additional elevation requirements, see the Flood Hazard Siting and Floor Elevation Criteria for Community Safe Rooms (fact sheet), and FEMA P-361.
In-ground safe rooms provide inherent protection from windborne debris naturally afforded by the surrounding soil coverage. Above-ground safe rooms are required to be rigorously tested to ensure that they can also provide protection from windborne debris. Therefore, all properly constructed safe rooms offer life-safety protection if they are properly designed and constructed or installed.
There are several possible locations in or near your home for a safe room. It can be either inside (within the building footprint) or outside (detached or adjacent to the existing ) and above-ground, in-ground, or in a basement. Many people prefer to build within their homes so they have some level of protection while attempting to access their safe room. For an existing home, this convenience must be balanced with the challenges of retrofitting the building. When determining where to locate a safe room, the owner must determine what is best for situation. For example, while an interior safe room offers the benefit of providing quicker accessibility, an exterior safe room may be easier to install for an existing building.
For more information on selecting the location of a safe room within your home or small business, see FEMA P-320, Section 3.5.
A homeowner who builds a safe room should be skilled in construction. It should be noted that the safe room door assembly cannot be constructed by a homeowner or contractor because ICC 500 requires that all storm shelter impact protective systems (including safe room door assemblies) demonstrate compliance with the standard’s testing requirements by labels attached to approved doors by third-party certification agencies. For more information on residential safe room doors, please refer to response provided for the question “Where Can I Find Doors And Hardware For My Safe Room?"
In addition to site-built residential safe rooms, there are also many prefabricated options available from safe room manufacturers. As noted in FEMA P-320 Section 4.2.2, anchorage of prefabricated safe rooms is critical to their performance in extreme wind events. More information on prefabricated safe room installation needs for above- and in-ground units can also be found in the Foundation and Anchoring Criteria for Safe Rooms fact sheet.
Yes, a safe room may be installed during the initial construction of a home or retrofitted afterward. However, building a safe room in an existing home typically costs about 20 percent more on average than building the same safe room in a new home under construction. When installing a safe room in an existing home, the adequacy of the foundation is a primary concern. A vast majority of slab-on-grade foundations in homes are not adequate to transfer the loads from a safe room to the ground, even if they have some level of reinforcement. When constructing or installing a safe room onto an existing slab, the slab should be inspected to determine whether it is sufficient to support the safe room. An architect or engineer should be consulted to ensure that any existing elements of the home (including the foundation) that are used as part of the safe room are adequate.
ICC 500 also requires any storm shelter installed on an existing slab using post-installed anchors (i.e., anchors installed in concrete that has already hardened) to be subject to special inspections. This requirement also applies to safe rooms. Helpful information on safe room foundations and anchoring can also be found in the Foundation and Anchoring Criteria for Safe Rooms fact sheet.
During the construction of a new home, the estimated basic cost to construct a safe room using the design plans in this publication ranges from approximately $9,400 to $13,100 for an 8-foot × 8-foot safe room and from $18,900 to $25,500 for a 14-foot × 14-foot safe room. The basic cost includes materials, labor and contingency but does not include the cost and installation of the safe room door assembly, which is addressed in the following section. Further, safe rooms installed in existing homes will be more expensive than those built as part of new construction. The cost of your safe room will vary depending on a variety of factors, including:
Prospective safe room owners are often surprised at the high cost of safe room door assemblies. Market research shows that entry level prices for properly tested and labeled residential safe room door assemblies are between approximately $2,500 and $3,200 (in 2021).
Residential prefabricated safe room costs, for just the units themselves and excluding site preparation and other costs, are approximately $5,000 to $6,000.
Section 4.3 of FEMA P-320 provides the assumptions and details of the cost estimates provided above.
For residential safe rooms, the usable tornado safe room floor area should include the protected occupant area between the safe room walls at the level of fixed seating, where fixed seating exists, minus the area of sanitary facilities or other items that impede usage of the safe room area. Table 3 shows the minimum safe room floor area per occupant for residential tornado and hurricane safe rooms.
| Weather Event | Residential Safe Room Types | Minimum Usable Floor Area per Safe Room Occupant |
|---|---|---|
| Tornado | One- and Two-Family Dwellings | 3 square feet |
| Other Residential | 5 square feet | |
| Hurricane | One- and Two-Family Dwellings | 7 square feet |
| Other Residential | 10 square feet |
*See FEMA P-361 for more information on usable safe room floor area.
Local jurisdictions generally do not require residential safe rooms or storm shelters. However, some communities have offered incentives (such as reduced property taxes) for owners who wish to build a safe room or storm shelter for their home. Some state and local governments have engaged in grant programs with the federal government to partially subsidize the construction of both residential and community safe rooms.
The 2015, 2018, and 2021 International Building Code® (IBC®) require the construction of community storm shelters to be included when K-12 schools and first responder facilities are constructed in areas where the storm shelter design wind speed for tornadoes is 250 mph. These storm shelters must comply with the adopted code’s referenced edition of the International Code Council’s (ICC) Standard for the Design and Construction of Storm Shelters, also known as the ICC 500.
ICC 500 provides the minimum design and construction requirements for extreme-wind storm shelters and has been incorporated by reference as a standard to be followed for storm shelter design and construction in the 2009, 2012, 2015, 2018, and 2021 International Building Code (IBC) and International Residential Code (IRC), as well as the 2018 and 2021 International Existing Building Code (IEBC). Those involved in the design, construction, and maintenance of safe rooms should become knowledgeable about both FEMA guidance and ICC code and standard requirements that pertain to sheltering from extreme winds. Knowledge of the information in these publications will help those involved navigate local applicable codes, employ best practices to provide near-absolute protection, and apply for FEMA funds that may be available (if desired).
