Save thousands of dollars by building your own earthbag dome tornado shelter. (See link below for free plans.)

Save thousands of dollars by building your own earthbag dome tornado shelter. (See link below for free plans.)

Designing an earthbag tornado shelter has been on my to-do list for years. My intent was to modify my free plans at Instructables.com (see below). Yesterday I can came across the following article at Yahoo and found out concrete tornado shelters are costing thousands of dollars. So I decided to write this blog post to summarize how to make your own storm shelter out of earthbags (sand bags), local soil, gravel, barbed wire and plaster. The dome shown above cost about $300 a few years ago. A smaller dome used only for emergencies could probably be built for half that cost if you eliminate the buttresses, the living roof (earth and plants on top) and are clever in making a door out of salvaged materials.

From Yahoo:
“Safe rooms feature thick steel walls and doors that can withstand winds up to 250 mph. They are typically windowless, with no light fixtures and no electricity — just a small, reinforced place to ride out the storm. Costs generally range from $3,500 to $6,000.
Sizes vary, but most hold only a few people. They can be bolted to the floor of a garage or custom-fitted to squeeze into a small space, even a closet. Some are so small occupants have to crawl inside. A few are buried in the yard like the old storm shelters of the late 1800s and early 1900s.
Before the twister devastated Joplin, the Neosho, Mo., safe room manufacturer called Twister Safe had four employees. Now it has 20.
“Business has probably quadrupled, at least,” owner Enos Davis said. “We’re selling 400 to 500 a year now, compared to maybe 100 before.”
Missouri’s choice spotlights a debate in states seeking better tornado protection: Is disaster aid better spent on safe rooms in individual homes or on larger public shelters designed to protect hundreds or thousands of people?
The downside of public shelters is getting there. Even with improvements in twister prediction, venturing out into a rapidly brewing storm is perilous.
“I wouldn’t get my family into a car and run that risk,” Joplin Assistant City Manager Sam Anselm said. “If you have the opportunity to put something in your house, that’s what we would encourage folks to do.””
Source: Yahoo

Build your own tornado shelter with free earthbag dome plans at Instructables.com — How to Build an Earthbag Dome. This earthbag dome Instructable will be featured in an upcoming book due out this fall along with other ‘best of” Instructables. You can read the original article in its entirety at Mother Earth News Magazine. The dome is 8’ in diameter and makes a great tool shed. You might want to build a smaller version for use as a tornado shelter. It’s easy to adjust the dome size by shortening or lengthening the string-lines used to create the radiuses.

Suggestions for reducing cost and labor: build no larger than needed (5’-6’ diameter might suffice for a storm shelter); build a sturdy steel door (an opening about 2’x3’ or 30” diameter would suffice); plaster the dome instead of using earth on top; eliminate the buttresses (not needed if the dome is tiny and there’s no living roof). Questions? Leave a comment below and I’ll be happy to respond.


Comments

How to Build a Low Cost Earthbag Tornado Shelter — 14 Comments

        • Yes, of course it’s safe. That’s why militaries all over the world have been building with sand bags for hundreds of years. They’re bomb and bullet resistant.

          Search the name of your state plus keywords ‘sand bags’ or maybe try ‘poly bags’. Try to find them as locally as possible because shipping is expensive.

  1. Has anyone been through an f5 tornado in one of these? If so, is it half berm or full berm? I have bad anxiety when it comes to tornadoes so before doing this I need to know what it is like in an f5.

    • You can build with no berm, partial berm or full berm. It doesn’t matter. Talk to any engineer. The wind will just blow around it because there are no flat surfaces for pressure to build up. The biggest weakness is the door, and that’s easy to secure with a steel bar inside.

      Edit: Use a full berm if there are big trees nearby that can fall on the dome.

  2. How many feet of an earth bag shelter need to be underground? I’m absolutely terrified of tornadoes, and I’m kinda in a panic to get one built fast. Please tell me the cheapest and easiest way. I’m on a very tight budget, but it has to be safe enough for my grandchildren. I’ll dig it myself if I have to.

    • How big do you want it? Roundhouse or dome?

      Free on how to build a roundhouse: http://www.instructables.com/id/How-to-Build-an-Earthbag-Roundhouse/

      You could add a ferrocement dome roof on top of the roundhouse. You could bolt a strong roof on top of the ferrocement dome to make it more durable and look better. Even if the roof blew off you’d still be protected with the dome roof.

      Wall depth: Dig a rubble trench and put about 3 courses of gravel bags on top. Continue with gravel bags until you’re above the level where moisture will cause problems (from splash or drifting snow).

      Add a really strong steel door, ventilation, bring in water and electric. Keep it small so it’s fast and easy to build. Add vertical rebar pins down through the inside of bags. Tubes are stronger than bags. Do everything correctly and you should survive a direct hit and even falling trees on top.

      In my opinion, every home in hurricane and tornado areas should have a shelter like this. Isn’t safety and peace of mind worth $500 to $1,000?

  3. No matter what material be used, the shelter must be at least half buried. You and the loved one must be under the ground level. Can be flooded? Not true. A $60 sump pump with a 120 V line, makes the difference.

  4. I think this is an excellent idea. Most people are not aware of it, but the civil defense shelters built in the last half of the 20th century in the US have been shut down and are not maintained.

    Switzerland has working nuclear bunkers for their entire population, located in every neighborhood throughout the country. In Israel, all new construction is required to have a bomb shelter built in each house/apartment.

    Now, we don’t have the same war worries that they do, but when a tornado hits, it is much like a bomb going off. All stick-built structures in the area are demolished, only the stone, concrete and brick structures survive. This should teach us something. If you live in tornado country, you really need to have a storm shelter nearby, if not in your house or yard. Buildings can be replaced, lives can’t, and earthbags offer an economical way of providing shelter and safety for yourself and your family.

    Always keep it stocked with appropriate emergency food, water and first aid supplies, and keep these fresh. A storm celler makes a good food storage unit. Buy, stock, and use the supplies that you normally enjoy, comfort in a disaster can be a real life-saver.

    • Well said. Your point about stocking some supplies is particularly important. You need space for people and supplies.

      And for those wondering if this will hold up through a tornado, don’t worry. Domes are one of the strongest shapes in nature and will easily withstand tornadoes and hurricanes. Our dome has about 20 truckloads of soil on top and it has never budged at all in several years. We could put another 20-100 truckloads of soil on top and it would not change a thing.

  5. Attention earthbag builders. The tornado shelter business is booming as documented in the Yahoo article. This could be a good time to build earthbag tornado shelters for profit. Even with paid labor, earthbag domes would be far less expensive than reinforced concrete storm shelters.

    • I’m sure the makers of the reinforced concrete shelters will be the first to say only theirs has been tested to tornado scale winds. “why take a chance with anything else” they’ll say. Has any earthbag structure taken a direct hit from a F1-F5 Tornado? My whole house will be earthbag so its a mute point for me :)

      • Every topic imaginable has been covered on this blog or EarthbagBuilding.com.

        Blog post on wind test: http://www.naturalbuildingblog.com/2011/05/03/wind-testing-of-earthbag-wall/

        Testing page: http://www.earthbagbuilding.com/testing.htm

        Wind test: 2011 Ross (U Florida Engineers Without Borders): Wind Testing of Earthbag Wall Abstract Out-of-plane displacement of 2.1 m ht x 3.6 m (7’-6” ht x 12’) unplastered, braced wall; tamped silty sand (no clay); solid poly bags 35 cm (14”) thick wall

        Note: The earthbag wall passed the test despite being poorly built with loose sand instead of the recommended moist, tamped clayey/sandy soil that’s allowed to dry. The final result should have been something approaching rammed earth, not loose sand bags!

Leave a Reply

Your email address will not be published. Required fields are marked *