**I'm willing to pass on any information that I've learned/compiled. I can't include step by step, as it would take up hundreds of pages. If someone else is wanting to take this on, I'll help how I can.
Thought I would post this because before I started mine I found little to no information out there. I've been researching/planning this project for a long time now, but finally started on it a little over a month ago. First off, I decided to go with a steel shelter. Concrete will crack over time, especially with moisture and temperature fluctuations. Cracks mean leaks. Fiberglass also cracks- where I live small earthquakes aren't that uncommon, so I decided steel because it will flex. The only downside to this that it will be susceptible to rust... but with coal tar epoxy coatings and cathodic anode protection, this thing will outlive me many times over. I'll explain that when I get to it in the posts.
I started out by purchasing 3/16ths plate and lots of 5lbs/foot c-channel (12 20 foot sticks). The material bill was right at $1800. This was right at 4000 pounds of metal. If you notice, commercially built shelters are all 10, 12, or some cheap ones even 14 gauge sheet metal. 3/16ths is almost twice the thickness of 10 gauge. I decided against shipping containers as they are 14 gauge- you can email me for more details if you want the argument of why they're not the best choice for underground shelters. Mine will be buried at least 1.5 foot underground. I will also have power and Ethernet feeds to the shelter. The final shelter will be 6 foot 1 inch tall inside, 10 feet long inside, and 6 feet wide inside.
Floor Bracing Complete: The floor is actually 12 foot long. This will give me a footprint bigger than the shelter itself to allow me the ability to use concrete to keep the structure from "floating".
Finished Floor (Medium).jpg
Beginning of Wall Supports:
Beginning Walls (Medium).jpg
First Wall (Medium).jpg
Results 1 to 10 of 15
03-21-2014, 11:22 PM #1
How to build an underground storm shelter tornado bunker
Last edited by rl.robertson; 03-22-2014 at 10:03 AM.
03-21-2014, 11:42 PM #2
I used a hydraulic engine hoist to maneuver some of the sides into place, and borrowed my neighbors front end loader for part of the work. I don't have access to a forklift, or this job would have been way easier!! I just cut small 1" pieces of c-channel to use as hooks, and welded it on my pieces. This made it easy to pick it up using a chain.
Second Wall (Medium).jpg
Welding Second Wall in Place: Note the upright folding table- it was windy and this blocked the wind from my shielding gas.
Second Wall Welds (Medium).jpg
I should've mentioned prior, I am making a welded seam along the outside and inside edges of this project. After I had my skeleton pieces in place for support, I welded along the bottom seams. After the seam was finished I welded the middle support. I then removed (cutting wheel on grinder) the supports that were holding the sides to continue the seam. Ultimately I welded the supports back in place after I had completely welded the seam.
I put a few structural braces along the top inside for the top to rest on , so that the roof could rest safely while I continued the outer skeleton.
As mentioned earlier, I used 1" drops of C-Channel to make the lifting hooks. I also used this approach previously to lift the walls.
C- Channel Hook to lift roof (Medium).jpg
Had to borrow my neighbor, and a few friends to get the roof in place. After raising it, we had to maneuver it and eventually slide it on top of the structural braces that I had previously welded across the top inside.
Sliding Roof Into Place (Medium).jpg
I'll be buying some beer and smoking some BBQ on that reverse flow (prior post) to thank these guys!.
After the roof was in place, I had a gap on one side. I improvised with pipe clamps to pull this in the best I could, and went to work with the wire. Got it filled in with a few passes.
Closing gaps with pipe clamps (Medium).jpg
More to follow.....
Last edited by rl.robertson; 03-21-2014 at 11:55 PM.
03-21-2014, 11:45 PM #3
I was able to bead the entire edges of the outside of the structure, and later finished the same on the inside. This will give me 2x the water protection just in case.
As I went along, I continued my exoskeleton to add strength to this shelter. You'll notice the c-channel is not spaced completely even. This is to compensate because of the overhead supports in place under the roof. This will distribute the topsoil weight more evenly over the frame of the structure.
Roof in Place (Medium).jpg
Using the C-Channel hook method, another piece was fit in to place on the end of the structure. I used pipe clamps to keep it held in to place while I began my welding. This piece alone weighs over 400 pounds, so I it was a task getting it fit in to place. The top will be trimmed off here shortly, and the drop will be used for the entry hatch.
End in place (Medium).jpg
To be continued.......
03-22-2014, 07:48 AM #4Senior Member
- Join Date
- May 2011
- Bossier Parish La.
In your original post, I am getting an invalid attachment specified, but I could see the rest.
Are you going to drag this to it's finally resting place or what?
I think the C channel would give more structural rigidity if it were turned the other way with the flanges to the sheet metal. Don't forget to give some consideration on ventilation for this before installing it. You may want to breathe some when y'all are in it. I think it would be a good idea to have the entrance door swing inward rather than outward. A tornado cold drop something across the doorway blocking you from opening it after the storm has passed. Then you would be dependent on someone clearing the doorway from the outside before you could get out.
03-22-2014, 09:24 AM #5Member
- Join Date
- Apr 2013
- metro Detroit
Wow that's impressive
03-22-2014, 09:31 AM #6Member
- Join Date
- May 2013
- Cantonment, FL
Ditto on not being able to see the attachments with the first post. All the others show up fine. Quite a project!!
03-22-2014, 09:33 AM #7
Thanks for all the advice. I'll see if I can fix the original attachments this evening. I'll be using a large excavator to dig the hole and lift and move the structure. A large backhoe has the lift, but where we live it's really sandy soil. An excavator gives me more lift capacity, and a longer reach so we don't sink an implement into the hole. The shelter will have powered ventilation with an air input and output. As for the door, I originally wanted an inward swinging one, but keeping out water I thought would be a challenge, and it would interfere with my stairs. I ultimately decided to implement a bottle Jack into the door so that I can lift the door if necessary.
If you have any ideas on a door that would open inward and work with those challenges- that would be better IMO.
About to get some time under the hood!
03-22-2014, 10:14 AM #8Senior Member
- Join Date
- May 2011
- Bossier Parish La.
03-26-2014, 07:21 AM #9Senior Member
- Join Date
- Dec 2013
- At the epicenter of the Green Mountain Range in VT
While I don't know what to suggest, Hurricane Irene in 2012 taught me to think outside the box. VT doesn't get storms. The statement isn't quite true. When everyone around me was prepping for a hurricane, I checked for trees that might be weak, knocked down any close enough to hit a building. The mountain brook is 200 yards away, and 50 feet in elevation below, I wasn't worried.
Hours before the full brunt of storm my neighbor called, the dry brook had water. Something that happened twice in the twentieth century. I walked out and watched. In five minutes water rose from a trickle to a raging river 18 feet deep, and 300 feet wide. Three hours later the water subsided. Though we don't appear on the flood maps, we were inundated. Chipmunk population hasn't returned.
03-27-2014, 07:12 PM #10Senior Member
- Join Date
- Aug 2004
- Milan Michigan
I wouldn't worry about the door opening outward, they should have a cell phone to call for help.
I would think it would be a good idea if the floor was 1' bigger all the way around so you would have the additional weight of the earth from being able to suck it out of the ground.
As far as the channel ribs, Yes they would have been stronger with the toes facing in verses out, however you would have gotten the most strength if the channel was on the edge.
Don't forget to use heavy duty hinges and hasps, Pipe and solid rod make some of the best verses the store bought.
Don't forget to break it in with your honey before the storm, You want to make sure it doesn't ROCK. Oh ya and a couple of cold ones.