The newly revised booklet on evaluating your risk and planning for and building an in-residence shelter is now available from the Federal Emergency Management Agency (FEMA). The booklet and plans can be ordered from or viewed on-line at FEMA Publications .
Call the toll-free number given (888-565-3896), give your name and address and a free copy of the booklet will be sent to you. The National Storm Shelter Association also has additional information regarding storm shelters and shelter construction.
If you are interested in purchasing a commercially made shelter, see the Tornado Project for a good discussion on important questions to consider and a list of companies which manufacture shelters.
Test reports for construction materials and performance conducted at Texas Tech University's Debris Impact Facility are here.
For more information on testing or to schedule a test, please contact Larry Tanner at (806) 742-3476 ext. 336 or send an e-mail to firstname.lastname@example.org.
Need for Shelters
- Save Lives
- Reduce Injuries
- Relieve Anxiety
Each year more than three billion man-hours are spent in the United States under tornado watches! In more than half the watches issued, a tornado occurs somewhere within the watch area. People in tornado prone areas experience anxiety and loss of productivity unless a safe place is readily available.
What is an In-residence Shelter?
A small windowless room, such as a closet or bathroom, readily accessible from all parts of the house, is designed to provide occupant protection. Such a shelter, inside the residence, becomes the "In-residence Shelter". The concept is applicable to both existing residences and newly constructed ones; the concept is practical whereas the cost of constructing the entire house to provide occupant protection is prohibitive.
Conception of the Idea
Post-storm inspections of hundreds of homes in more than 90 towns and cities struck by tornadoes revealed that in many instances a small room in the central portion of the house remained standing even when the house was severely damaged or completely destroyed (see Figure 1). The idea was then conceived that these interior rooms could economically be strengthened to provide a high degree of occupant protection.
Personnel of the National Wind Institute at Texas Tech have conducted extensive research to better understand and mitigate the effect of severe winds. More than 90 windstorms have been investigated across the country so that damage can be better understood and designs for mitigation developed.
Wind-resistant building research, design and extensive testing are conducted on campus.
Advantages of the In-residence Shelter
- Low Cost
- Multiple Use
The accessibility of a shelter within the house makes the in-residence shelter highly advantageous over an outdoor cellar or community shelter because it eliminates the extreme danger of being struck by flying debris while attempting to reach a cellar or community shelter. Unlike the cellar, the in-residence shelter has a daily functional use–bathroom, closet, utility room, etc. It permits a family to continue regular living patterns during a weather watch with the peace of mind of knowing that a place of safety from extreme winds is only a few seconds away.
Properly reinforced basements with concrete roofs offer safe and readily accessible shelters from storms, but in many areas of the country they are not commonly provided in residences. The cost of an in-residence shelter is substantially less than that of a basement.
Requirements for the In-residence Shelter
- Good Accessibility
- Resistance to Wind Forces
- Adequate Fasteners
- Adequate Coverage
- Resistance to Missile Perforation
For the in-residence shelter to be effective, it must be readily accessible from all parts of the house. The central portion is the favored location, for added protection as well as accessibility.
The in-residence shelter must be able to resist the forces that extreme winds or interacting structural components place upon it. The in-residence shelter is designed to withstand wind speeds of 250 mph, which accounts for virtually all tornadoes which have occurred in the U.S.
Adequate fasteners are the key to satisfactory structural performance of the shelter. The roof must be securely anchored to the walls, the walls to each other, and the walls to the foundation. These connections are necessary to insure structural integrity and to prevent the shelter from overturning.
Ventilation should be provided when the shelter is intended to provide protection from hurricanes.
Tornado-generated missiles (flying debris) create the greatest threat to occupants of homes that are struck by severe wind. These missiles, very often, perforate conventional walls and roofs. In order to provide a high degree of occupant protection, the shelter must be designed to prevent perforation by missiles on all surfaces–walls, roof and door.
The missile chosen for shelter design is a 2x4-inch timber plank weighing approximately 15 lbs., striking on end at 100 mph for walls and doors and at 67 mph for roof/ceilings. Texas Tech has conducted extensive testing by using a compressed air cannon to thrust missiles at various building sections. The concepts presented below reflect this research; each concept provides protection against the timber missile.
In order to minimize cost, only readily available construction materials are employed in the concepts presented. No new technology or unusual building skills are required in construction.
- Reinforced Concrete Masonry
- Plywood and Steel on Wood Studs
One proven concept involves 6- or 8-inch thick concrete masonry units reinforced with conventional reinforcing bars; the cavities in the block are filled with concrete. Insulating concrete forms may be substituted for the concrete blocks.
Wall reinforcing should extend beyond the top of the wall and should be bent over to tie into the reinforced cast-in-place concrete ceiling slab. See Figure 2.
The plywood and steel on wood studs concept was developed for retrofitting existing homes with concrete slab foundations. All construction can occur on either side of the walls of an existing room. Layers of plywood and heavy gauge sheet-metal are installed on the stud walls in a sequence specific to the wall side selected for retrofit. See Figure 3. This concept requires specific anchorage of wall sill plates to the slab and the walls to the new ceiling joists installed below the existing ceiling. The shelter walls and ceiling structure must be isolated from the surrounding house structure.
A number of missile-resistant doors have been developed which withstand the wind forces and stop the design missile. The door can be either field fabricated or store bought. The fabricated door is comprised of two thicknesses of 3/4-inch plywood glued together and covered on the outside with 11-gauge sheet steel. The door must be supported on both sides and is best mounted in a pocket inside the shelter and used only when the room is occupied as a shelter. A conventional door with the usual finishes and accessories can be installed for normal use.
The manufactured door consists of a hollow metal door and frame of 14-, 16- or 20-gauge metal skins. Metal doors can be purchased from most home improvement centers. The 16- and 20-gauge doors must be strengthened with a single layer of 14-gauge steel on one side of the door.
The sliding hardware for the pocket door is available at most metal building systems retailers. The swing door hardware includes three heavy duty hinges and three residential grade mortise deadbolts. Surface mounted slide bolts may be used, but the deadbolts are preferable because that are unlockable from either side of the door.
Custom Designs or Modifications
Research has produced the general concepts presented herein. Custom designs or modifications should be developed or checked by a registered professional engineer. Standard designs are available from the Federal Emergency Management Agency (FEMA) by calling their toll-free number 888-565-3896 or by downloading them from the FEMA website.
Funding/Low Cost Loans for Safe Rooms
The U.S. Department of Housing and Urban Development is providing mortgage insurance to enable homebuyers to borrow up to $5,000 to create windstorm shelters in their homes.
If you live in Arkansas you may be eligible for partial reimbursement of the cost of installing a safe room.
Mississippi has instituted a safe room initiative for counties within the federally-declared Disaster Area.
Texas veterans who qualify for a home-improvement loan from the Texas Veterans Land Board may be able to apply that loan to safe room installation.
Frequently Asked Questions
WARNING: INFORMATION PRESENTED ON THIS WEBSITE IS INSUFFICIENT FOR CONSTRUCTING AN IN-RESIDENCE SHELTER.
For more information on protecting your family and home including tips for wind-resistant construction see Protection from Extreme Wind.
For design guidelines for community shelters, order or download Design and Construction Guidance for Community Shelters from FEMA.
Are you an inventor, builder or engineer who designs or wants to design a tornado shelter? See the National Performance Criteria for Tornado Shelters from FEMA and Texas Tech.