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.
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.
Additional information is available on our other FEMA Safe Room pages.
A common misconception about safe room doors is that they must swing in a particular direction – inward or outward. According to ICC 500, the pressure testing on a door must be conducted away from the door stop, meaning that the door is pressure-tested in the weakest condition regardless of being in-swinging or out-swinging. Additionally, a door must undergo the missile impact resistance testing in the configuration that will be used for installation.
Beyond code requirements, both inward- and outward-swinging doors have benefits. For example, inward-swinging doors are less likely to be blocked by debris, while outward-swinging doors provide more usable space within the safe room.
In some states or communities, the applicable building code may require that doors swing in a particular direction. For information on code requirements for your jurisdiction, contact a local building official or licensed design professional in your area.
How to measure your bottom (lowest) floor and whether your home meets the BFE requirements is determined by your community’s building codes and floodplain management regulations, and the flood zone in which your home is located.
The term “lowest floor” is defined by the NFIP and building codes. It refers to the portion of the building that is raised above the ground on an elevated foundation. In Zone A, the elevation of the “lowest floor” is measured at the top of the floor of the elevated building. In Zone V, the elevation is measured at the bottom of the lowest horizontal structural member (beam) that supports the elevated building.
To comply with the NFIP and building codes, a building must have its lowest floor elevated to or above the specified elevation, usually the BFE or higher. The only way to know for sure if your home is elevated high enough to comply with the requirements is to have a licensed surveyor prepare an Elevation Certificate. If your home was built in accordance with floodplain management rules in effect at the time it was constructed, your community may have a record of the surveyed information.
References: FEMA. 2012. Quick Reference Guide: Comparison of Select NFIP and Building Code Requirements for Special Flood Hazard Areas. Washington, DC. March 2012.
Although flood openings on interior walls are not explicitly required by the NFIP, FEMA Technical Bulletin (TB) 1, Openings in Foundation Walls and Walls of Enclosures (2008), suggests that interior enclosed areas that do not have any exterior walls should have openings to ensure water reaches all enclosed areas in order to minimize unbalanced hydrostatic forces (top of page 17). This is especially important if one of the interior walls is load bearing. It is recommended that you use the same number of openings that would be used if the interior enclosed area had an exterior wall.
Flood openings installed on interior walls do not count towards the required total net area of flood openings. Although flood openings on interior walls do not count towards the required total net area of flood openings, it is recommended to install flood openings on interior walls between enclosed areas. Installing flood openings on interior walls is important to relieve unbalanced hydrostatic forces on the wall.
References: FEMA. 2008. Openings in Foundations Walls and Walls of Enclosures in Special Flood Hazard Areas in Accordance with the National Flood Insurance Program. NFIP Technical Bulletin 1. Washington, DC. August 2008.
Technical Fact Sheet No. 7.5 in FEMA P- 499, Home Builder’s Guide to Coastal Construction (FEMA 2010a), provides retrofit criteria for each type of attic ventilation opening, including soffits. The most critical soffit installations are those with vinyl or aluminum soffit panels. Aluminum soffit panels may also be vulnerable because of aluminum’s corrosion potential in an environment with salt-laden air. If the house is within 3,000 feet of a body of water that produces salt spray, it is recommended that aluminum soffits be completely removed and replaced with a soffit system installed per the guidance of Technical Fact Sheet No. 7.5. Furthermore, Figure 4-12 of FEMA P-804, Wind Retrofit Guide for Residential Buildings (FEMA 2010b), shows a typical soffit detail for retrofitting existing soffits to improve wind and water resistance. It should be noted that while many homes may have different soffit configurations than shown in Figure 4-12, the basic intent of the retrofit in the figure—reduction of long spans by installation of intermediate supports and application of continuous edge support—should be applied in any situation. For improved wind and water resistance, soffits should be secured using sealant and screws as described in Technical Fact Sheet No. 7.5. The selected soffit product may have more restrictive installation instructions when installed in high-wind regions, in which case the more restrictive installation method should be followed.
References:
A6. Depending on the set-up of the user’s computer, administrative rights may be required for the installation of the tool. The need for administrative rights is set by the agency, community, or other entity that is responsible for the security and maintenance of the user’s computer. The installation options and the need for administrative rights are available in the FEMA SDE Read Me - SDE 3.0 Tool Installation Guide and the FEMA Substantial Damage Estimator (SDE) User Manual and Field Workbook. Both documents are available on the same website.
Due to federal regulations, FEMA does not endorse, approve, certify, or recommend any contractors, individuals, firms, or products. Contractors, individuals, or firms shall not claim they or their products are “FEMA approved” or “FEMA certified.” You should work with a registered design professional, such as an architect or engineer, who is familiar with safe rooms to verify that your safe room meets or exceeds current FEMA criteria.
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.
As noted in Chapter 4 (Consumer Guide) of FEMA P-320, your State Hazard Mitigation Officer (SHMO) may be able to recommend a qualified safe room inspector. A list of SHMOs can be found at https://www.fema.gov/grants/mitigation/ state-contacts.
The age of the safe room or storm shelter is a key factor in determining which criteria were in effect when the product was designed and constructed or installed. FEMA P-361 was introduced in 2000 and updated in 2008, 2015, and 2021. ICC 500, which is referenced in the model building codes and includes the minimum requirements for residential and community storm shelters, was first published in 2008 and updated in 2014 and 2020.
Lastly, an independent RDP licensed in your state and familiar with safe room design and construction may also be consulted to verify that the safe room meets or exceeds the criteria found in FEMA P-361 or ICC 500.
