FEMA 320- Taking Shelter From the Storm 

Section III: 
Building Your Shelter


Your builder/contractor can use the design drawings in this booklet to build a shelter for 
any of the wind zones shown on the map in Figure I.2. The design drawings provided 
include the details for building ve types of shelters: concrete, concrete masonry, 
wood-frame, lean-to, and in-ground. Each of these alternatives is expected to perform 
equally well in resisting material fatigue and connection failures caused by extreme 
winds.

The materials and connections were chosen for their "ultimate strength," which means 
that the materials are expected to resist the loads imposed on them until they or the 
connections between them fail. The forces of extreme winds may cause cracks or 
other signs of stress in the materials or connections, and they may cause materials or 
connections to yield. However, the intent of the designs is not to produce a shelter that 
will always remain completely undamaged, but rather a shelter that will enable its 
occupants to survive an extreme windstorm with little or no injury. The shelter itself 
may need to be extensively repaired or completely replaced after an extreme wind 
event.

The shelter size and materials specied in the drawings are based on principles and 
practices used by structural engineering professionals and the results of extensive 
testing for effects of missile impact. Before increasing the shelter size or using material 
types, sizes, or spacings other than those specied in the drawings, review the changes 
with a licensed professional structural engineer.

The information in this section includes the following:

 design drawings and details for shelters in basements, above the ground, and in the 
ground

 designs for both slab-on-grade and crawlspace foundations

 general design notes and fastener and hardware schedules


 materials lists with quantities and specications


The Wind Engineering Research Center at Texas Tech University has been involved in 
shelter design for many years. If you or your builder/contractor have questions about 
the design drawings in this booklet, call the Wind Engineering Research Center at (888) 
946-3287, ext. 336 for technical guidance.

The following is an index of the design drawings provided in this booklet:

Sheet No. Drawing No.* Title 

 1 of 16 1 Index Sheet 
 2 of 16 2 General Notes 
 3 of 16 IG-1 In-Ground Shelter - Sections and Details 
 4 of 16 B-1 Basement Lean-To 
 5 of 16 B-2 Basement Shelter - Corner Location 
 6 of 16 AG-1 CMU/Concrete Alternative Plans 
 7 of 16 AG-2 CMU/Concrete Wall Sections 
 8 of 16 AG-3 CMU/Concrete Sections - Ceiling Alternatives 
 9 of 16 AG-4 Wood-Frame Shelter Plan - Plywood Sheathing w/ CMU Inll 
10 of 16 AG-5 Wood-Frame Shelter Plan - Plywood and Steel Wall Sheathing 
11 of 16 AG-6 Wood-Frame Shelter - Foundation Sections
12 of 16 AG-7 Insulating Concrete Form - Plans
13 of 16 AG-8 Insulating Concrete Form- Sections
14 of 16 14 Misc. Details
15 and 16 of 16 15 and 16 Materials Lists 

* IG = In-Ground,  B = Basement,  AG = Aboveground



How To Use the Drawings

 Drawings shall not be scaled to determine dimensions.

 If there is a conict between a dimension shown on the drawings and a scaled 
dimension, the dimension shown on the drawing shall govern.

 If there is a conict between the drawings and local codes, the local codes shall 
govern.

 If there is a conict among the general notes, specications, and plans, the order of 
precedence is notes, then specications, then plans.