How to Build a Storm Shelter

Posted by Jeff Turner on Tue, Mar 26, 2013 @ 11:04 AM

As you can see from the ‘shelter bus,’ folks can get pretty crafty when it comes to building their own storm or tornado shelters.

how build a storm shelterWe give these innovators creativity points. But when it comes to staying safe from a tornado, you want strength and security on your side, not creativity.

Because safety is our main concern, we’ve developed a seven-step guide for innovators looking to build their own storm shelter.

Before you start building, here’s something to keep in mind:

The cost of building your own storm or tornado shelter is 40 to 50 percent more, plus tax, than purchasing a National Storm Shelters unit.

The reason? You’ll most likely be paying full retail price for the 100+ required materials, as well as paying for renting installation and manufacturing machines and hiring one or two laborers – who may not have storm-shelter specific experience. You’ll find more detail on these costs below in our seven-step guide to building your own storm shelter.

A Step-By-Step Guide To Building Your Own Storm Shelter:

Step One – Identify your storm shelter’s location

The safest shelters are located inside your home, or as close to it as possible, so when you take refuge from the storm, you avoid stepping into the storm you are fleeing. If your shelter is installed in your back yard, like the school bus shelter, you may be forced to forge through dangerously high winds and bruising hailstones just to take shelter. That defeats the point.

Step Two – Determine your storm shelter’s dimensions

How many family members and friends are you hoping to accommodate in your storm or tornado shelter? FEMA 320 standards require three square feet per person. That’s the standard we adhere to at National Storm Shelters and it’s what we recommend if safety is your top concern.  

*Equipping your home with a FEMA-standardized storm shelter will keep your family safe while adding value to your home. The converse is also true. Shelters that do not adhere to FEMA standards are not guaranteed safe and may negatively affect your home’s resale value.

Step Three – Select fabrication materials

Concrete block, fiberglass and galvanized steel are the most typical storm shelter materials. Here are the pros and cons:

  • Concrete block – This material is easy to come by, and cheaper than other options, but concrete is porous. Water will undoubtedly penetrate your storm or tornado shelter – which means you may find a foot or more of water in your storm shelter when you need it in an emergency, which is no time to start bailing.

  • Fiberglass – This option is cost effective and waterproof, but fiberglass will “sweat,” which causes dangerous mold. To remediate this, you must clean and paint the structure regularly. Also, fiberglass is insubstantial without significant reinforcement. A severe storm’s pressure can create a vacuum, which will cause a fiberglass shelter that’s backfilled with dirt to pop out of the ground. To counteract this you must reinforce the fiberglass shelter by bolting it to a concrete casing.

  • Galvanized steel – This is our preferred storm and tornado shelter material. Steel can last a lifetime,how to build a storm shelterrequires little to no maintenance and is very sturdy. The only con, if any, is its cost (especially if you’re purchasing at full retail value). This is the most expensive material because it’s the best. The amount required for a typical storm or tornado shelter will cost upwards of $1,800. For additional safety and durability, we dip our galvanized steel storm shelters in zinc and then encase them in solid concrete. The zinc required adds up to more than $300 and the poured concrete totals at approximately $400.

*Learn more about the different types of storm and tornado shelters on our blog.

Step Four – Purchase miscellaneous fittings

A finished storm or tornado shelter has more than 100 parts, including bolts, fasteners, bearings, lock nuts, etc. You’ll need a toolbox full to complete your project.

*Purchasing these materials at retail will cost twice as much as manufacturer reserved wholesale prices.

Step Five – Build your own storm shelter

You can build your storm shelter while you’re installing it, or you may choose to prefabricate it and then install it. Whatever your path, all storm shelters should be assembled by experienced craftsmen who are experienced with the materials you've chose.

how to build a storm shelter

Amateur manufacturing can severely affect your shelter’s usefulness – and safety. In fact, a poorly made shelter can actually do more harm that good, as you are surrounded by materials that can be turned into weapons by high winds. If you’ve never worked with the materials you’ve chosen for your shelter, we highly suggest hiring someone who has. After all, your family’s safety is not worth gambling.

  • An experienced welder charges an average rate of $65 per hour. Storm shelter manufacturing requires approximately 20 hours. That’s about $1,300 in manufacturing labor alone. *This doesn’t include installation labor.

  • After manufacturing the structure, you’ll want to add benches ($100) and lights ($25) to the interior, and a come-a-long ($125) and safety chain ($25) to the door.

Step Six – Rent installation and excavation equipment

Depending on your location and storm shelter type, you may need to rent or purchase several different machines, including some heavy equipment. Here are a few examples and their estimated cost per day:

  • Concrete vibrator – $80

  • Diamond blade – $90

  • Dump truck – $300 to $400

  • Georgia buggy – $250

  • Hydraulic rock hammer – $260

  • Mini-excavator – $325

  • Pressure washer – $65

  • Wet saw – $125

how to build a storm shelterStep Seven – Install your storm shelter

Monitor your local forecast for mild, rain-free days to plan your install. If you’re installing in your attached garage, rain will alter the properties of the dirt. If you’re installing outdoors, the rain will cause your newly submerged unit to float.

We estimate these costs already adding up to $5,620 – and that’s without accounting for unskilled labor, opportunity cost, multiple-day machine rentals and miscellaneous parts like nuts, bolts, fasteners, bearings, locks, etc.

Every year 1,200 tornadoes strike the U.S. Without a secure tornado shelter, your life is at stake. National Storm Shelters is backed by nearly 20 years offabrication and manufacturing experience. We proudly deliver what we, and our customers, consider the safest shelter on the market. Click here to watch how we build tornado storm shelters

If you decide building your own storm shelter is not the right choice for you, give us a call at (615) 223- 7233 for a free quote, and click below to download our guide about how to select the right storm shelter.

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