Under ground shelter/root cellar

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Brent S

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I've been making a storm shelter for a while now, so I just decided to post the progression of it. I still have a long way to go, but work a little on it at a time. I'm no expert on building, but was a general contractor for 20 yrs. so I'll be glad to try and help if anyone has any design questions for one of their own. I am certain of one thing, dirt is a lot heavier than people think. So before you go burying anything, make it twice as strong as you think it needs to be. Another note, cargo containers are not strong enough to be buried without a lot of reinforcement, no matter what you've heard. I wasn't really planning to build this thing now, but had rented a backhoe for a week, and when I finished doing the work with the machine early I decided to dig the hole for the shelter/root cellar that I've always wanted. I didn't take Picts of the footer, but it's basically a trench with two pcs of rebar in it, filled with concrete. The only part that takes any thought is placing the vertical rebar at the center of each block hole. Measure twice as it's not movable once the concrete sets. As you can see, I poured the floor after setting some of the wall blocks. This way I have a slab of concrete to stop the compression of the walls when I backfill. It also makes it a little more water proof verses building the wall on top of the slab. I put in a small drain around the perimeter of the walls and filled with gravel. I also coated the outside of the block with a fibered roof/foundation coating. Just before I backfill I will wrap it with tar paper too. One helpful hint is don't put full size rebar all the way up the walls. I went half way up, and when the blocks got high enough, I tied together the rest of the rebar to reach the roof. Sliding heavy block all the way down 8 ft of rebar would be tough! I'm almost done with the walls finally, and will post Picts of the forming of the roof as I get to it.
 

Silent Bob

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View attachment 3388 View attachment 3389 View attachment 3390 View attachment 3391 View attachment 3392 View attachment 3393 I've been making a storm shelter for a while now, so I just decided to post the progression of it. I still have a long way to go, but work a little on it at a time. I'm no expert on building, but was a general contractor for 20 yrs. so I'll be glad to try and help if anyone has any design questions for one of their own. I am certain of one thing, dirt is a lot heavier than people think. So before you go burying anything, make it twice as strong as you think it needs to be. Another note, cargo containers are not strong enough to be buried without a lot of reinforcement, no matter what you've heard. I wasn't really planning to build this thing now, but had rented a backhoe for a week, and when I finished doing the work with the machine early I decided to dig the hole for the shelter/root cellar that I've always wanted. I didn't take Picts of the footer, but it's basically a trench with two pcs of rebar in it, filled with concrete. The only part that takes any thought is placing the vertical rebar at the center of each block hole. Measure twice as it's not movable once the concrete sets. As you can see, I poured the floor after setting some of the wall blocks. This way I have a slab of concrete to stop the compression of the walls when I backfill. It also makes it a little more water proof verses building the wall on top of the slab. I put in a small drain around the perimeter of the walls and filled with gravel. I also coated the outside of the block with a fibered roof/foundation coating. Just before I backfill I will wrap it with tar paper too. One helpful hint is don't put full size rebar all the way up the walls. I went half way up, and when the blocks got high enough, I tied together the rest of the rebar to reach the roof. Sliding heavy block all the way down 8 ft of rebar would be tough! I'm almost done with the walls finally, and will post Picts of the forming of the roof as I get to it.

You are so right on the cargo container Brent! For new readers, if your thinking of this option or have had success, post your projects on DPF. I'd be interested in seeing them. For me, they are just a disaster waiting to happen, unless you don't reinforce them, which a bunch of people don't do. The containers are not built to handle the PSI once you begin to fill the sides and top of the container. We are not even talking about the concerns I have at placing that much weight of soil and fill on top of the roof, which is hardly reinforced at the top of the container, nor the sheeting used for the container top is rated for that level of stress.

I've seen on that last National Geo DDP show of the guy who lived 1 hour from Dallas and how he converted a container in the ground. I am just not sure it is very safe, granted, I don't think he has it sunk deep like a true shelter would be...based on how many steps he made (which I counted 6, that would mean, he sunk the base of the container down to about 15 feet deep. I am not sure how he constructed his outer retaining wall and whether the base was made of concrete. My take at least 8 inches of fill concrete would be enough to support the container. I think the guys container was a 40 footer. I didn't see any reinforcement span at the top, which I've seen with some folks, which means...whenever, we get out of the drought, his container might be in jeopardy of a collapse. I know the NG DDP show focused on his escape hatch (Dog house), but I think the guy constructed the escape hatch out of tin sheeting, didn't look very strong, which is another concern, granted, his was not a typical escape hatch, which should be filled with about 3-4 feet of lose fill/sand...so that it does not give access to the OPFOR.

We've talked you and I about this idea way before you began the construction, I think your project is super! You've spent a ton of time on it and I think once completed it will support all your intended ideas. Good job my friend! Love the pictures. Hope others are taking note on the construction and the amount of rebar that is being placed in this project. In my opinion, the more rebar and the right concrete mix with proper curing...your project will withstand a bunch of scenarios.
 

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UNDERGROUND STORAGE! A fantastic idea. Great work, ideas, and execution too from what I see. Thanks for the post.
 

tr2212

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Thanks for posting this!

I have been thinking about this since I started prepping several months ago.

My questions are: do I pick a DIY shelter like this, or expensive pre-fab, AND how do I keep water out without a pump (EMP backup plan). Example: pooling water at the bottom of a staircase and/or keeping water from coming in through the hatch or door (depending on whether it's pre-fab or DIY).

I'll use the newbie card here and say that my descriptions probably stink, so let me know if that doesn't make sense. :)
 

Brent S

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You are so right on the cargo container Brent! For new readers, if your thinking of this option or have had success, post your projects on DPF. I'd be interested in seeing them. For me, they are just a disaster waiting to happen, unless you don't reinforce them, which a bunch of people don't do. The containers are not built to handle the PSI once you begin to fill the sides and top of the container. We are not even talking about the concerns I have at placing that much weight of soil and fill on top of the roof, which is hardly reinforced at the top of the container, nor the sheeting used for the container top is rated for that level of stress.

I've seen on that last National Geo DDP show of the guy who lived 1 hour from Dallas and how he converted a container in the ground. I am just not sure it is very safe, granted, I don't think he has it sunk deep like a true shelter would be...based on how many steps he made (which I counted 6, that would mean, he sunk the base of the container down to about 15 feet deep. I am not sure how he constructed his outer retaining wall and whether the base was made of concrete. My take at least 8 inches of fill concrete would be enough to support the container. I think the guys container was a 40 footer. I didn't see any reinforcement span at the top, which I've seen with some folks, which means...whenever, we get out of the drought, his container might be in jeopardy of a collapse. I know the NG DDP show focused on his escape hatch (Dog house), but I think the guy constructed the escape hatch out of tin sheeting, didn't look very strong, which is another concern, granted, his was not a typical escape hatch, which should be filled with about 3-4 feet of lose fill/sand...so that it does not give access to the OPFOR.

We've talked you and I about this idea way before you began the construction, I think your project is super! You've spent a ton of time on it and I think once completed it will support all your intended ideas. Good job my friend! Love the pictures. Hope others are taking note on the construction and the amount of rebar that is being placed in this project. In my opinion, the more rebar and the right concrete mix with proper curing...your project will withstand a bunch of scenarios.
Thanks for posting this!

I have been thinking about this since I started prepping several months ago.

My questions are: do I pick a DIY shelter like this, or expensive pre-fab, AND how do I keep water out without a pump (EMP backup plan). Example: pooling water at the bottom of a staircase and/or keeping water from coming in through the hatch or door (depending on whether it's pre-fab or DIY).

I'll use the newbie card here and say that my descriptions probably stink, so let me know if that doesn't make sense. :)
Thanks for posting this!

I have been thinking about this since I started prepping several months ago.

My questions are: do I pick a DIY shelter like this, or expensive pre-fab, AND how do I keep water out without a pump (EMP backup plan). Example: pooling water at the bottom of a staircase and/or keeping water from coming in through the hatch or door (depending on whether it's pre-fab or DIY).

I'll use the newbie card here and say that my descriptions probably stink, so let me know if that doesn't make sense. :)
I guess I've always been a DIY person, so for me it was no question to do it myself, not to mention there isn't a chance in hell I could afford to buy a prefab one. Even this will cost a respectable couple thousand before I'm all done, but I am pretty good a scavenging materials and fabricating things on the fly, so I hope to keep it under that. So far I have about six hundred in it, but the door and escape hatch are going to be an interesting challenge. The air intake is pretty simple, and I thought about electricity, but decided it's not reliable in the event of a disaster or storm anyways so I'm opting for battery powered light. I will put a hand crank fan for the air intake.
My take on water issues is don't build where it can take on water, period. I was lucky to have a hillside that is high above the water table, so all I have to deal with is rain water percolating thru the ground. If you're in a low area and have to depend on electricity and pumps to keep it dry, move it. Mounding is a great option. The movie The Hobbit showed what is possible with a little imagination, and a couple feet of earth gives a great amount of insulation and protection. My hillside dig has one flaw as the front wall is still exposed and won't have the insulating factor. I could make a second wall and fill between them, but will see how the temperature inside holds before deciding on it. 5 sides with geothermal protection hopefully will keep it cool. The front wall will be 8in solid concrete, and I will shade it with a metal roof for rainwater collection, so I'll post what temps I can maintain inside. This won't be a quick project, but I will continue posting Picts as I progress.
 

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Several years ago we acquired one of those oversea containers, I did quite a bit of research on burying that thing...needless to say...it still sits on top of the ground! Since the hole has to be dug whichever...I have decided I would feel safer in the block/rebar walls! I am deathly afraid of tornadoes!

I am sooo jealous! I had a root cellar years ago...I will have another one...some day! Hubby has several pieces of earth moving equip...front end loader and I think a back hoe...I really wish someone would teach me how to use those things...this is year three that I have been waiting on him to do anything other than work at the neighbors place! I keep hearing they are working the bugs out! You must be a master mechanic to even drive a vehicle he owns...much less operate a piece of his equipment! That is why I haven't learned...I should probably get a little more aggressive in insisting that he teach me!

Thanks for sharing and please keep posting progress!
 

Brent S

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Several years ago we acquired one of those oversea containers, I did quite a bit of research on burying that thing...needless to say...it still sits on top of the ground! Since the hole has to be dug whichever...I have decided I would feel safer in the block/rebar walls! I am deathly afraid of tornadoes!

I am sooo jealous! I had a root cellar years ago...I will have another one...some day! Hubby has several pieces of earth moving equip...front end loader and I think a back hoe...I really wish someone would teach me how to use those things...this is year three that I have been waiting on him to do anything other than work at the neighbors place! I keep hearing they are working the bugs out! You must be a master mechanic to even drive a vehicle he owns...much less operate a piece of his equipment! That is why I haven't learned...I should probably get a little more aggressive in insisting that he teach me!

Thanks for sharing and please keep posting progress!
Digging the hole is the toughest part, so you're allready half way there with the right equipment. A backhoe isn't very tough to learn, just go slow until you get comfortable with it. I mortared the blocks together, as I feel it's a little more water tight, but there's another easier way. You can just stack the block, and use a product called surface bonding cement. It's like stucco, with fine fibers in it. After stacking a few rows of block you stuck on this product, on both sides of the wall and it's actually stronger than mortared joints. Then stack a few more rows and stucco them, until you get to the top. The block are nothing more than a form to pour the concrete into, so they don't need to be real pretty. Once I am done with the shelter I will line all the walls floor to ceiling with storage shelving, so I really won't see anything but the ceiling.,
 

GunnarCarr

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I have recently decided I wanted to do something like this for a Bol. But I was thinking digging 3-4 feet down and lining it with cinder block then doing a debris pile to give another 2-3 feet overhead. Will I need do do the slab underneath? This is just for a camp location for a day or two at a time.
 

Akingu

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The only problem I can foresee is the slab/block floor which will separate when it settles thus allowing water to see in from the floor. Are you filling the blocks with concrete too or dirt? Solid blocks will stop water seepage longer.
 

jontte

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I don'tknow if this will help,but here in Fin we use, to prevent water to come in, some rubbercarpet which is glued to the wall with tar,keeps water out of basement, and as observer only, seems to be quite easy to apply
 

Brent S

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I have recently decided I wanted to do something like this for a Bol. But I was thinking digging 3-4 feet down and lining it with cinder block then doing a debris pile to give another 2-3 feet overhead. Will I need do do the slab underneath? This is just for a camp location for a day or two at a time.
Your not going to have the stresses of all the weight from the dirt at 3 or 4 feet as you would at 8 ft, so that helps. I still would pour the floor as it will give you a good level surface, and will help with water intrusion. Even at 3 foot high, you still need a footer with rebar in it, and yes you do need to fill the blocks with rebar and concrete. The weight of the dirt may not collapse the walls right away, but over time, the weight is pushing on it 24/7, it will tend to crack and move without reinforcement. Poured walls are the best, the only problem with blocks are the joints. Even when you fill the blocks with concrete the ends or but joints are a weak spot for water intrusion. You need some sort of drain at the bottom and to seal the walls. I hear from people all the time that are trying to stop a leak in their basement. After the backfill is not the time to waterproof anything. A little extra work during construction will make it a lifelong investment.
 

Brent S

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I don'tknow if this will help,but here in Fin we use, to prevent water to come in, some rubbercarpet which is glued to the wall with tar,keeps water out of basement, and as observer only, seems to be quite easy to apply
I wish I had access to some inexpensive rubber sheeting. I used a fibered asphalt coating on the outside of the blocks and will put tar paper around it as I backfill. It works well, but you flat out cannot over prepare to keep water out! The whole point of this is to have a dry, dark and cool place to store things, not to have a dank, moldy hole in the ground. I'm only shy about twenty blocks to lay to finish the walls, but had a shoulder injury and am not feeling like messing with blocks just yet. I laid a few since, (boy am I chaffed:)), sorry, couldn't resist, but it's really hard to mess with block with mostly one hand. Hopefully next weekend I'll finish and will start forming for the roof and wall pour. Then goes in the ceiling rebar and I get to call a concrete truck!!!! I'll keep posting Picts.
 

jontte

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have a question to all you builders,we all know those containers, nicely built,but not so good if you bury them under ground without reinforcements..
what if you bury it only partially,and have some drainege to transport water away from it naturally, then cover the top part with soil..is this feasible or just a dumd idea??
 

Brent S

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have a question to all you builders,we all know those containers, nicely built,but not so good if you bury them under ground without reinforcements..
what if you bury it only partially,and have some drainege to transport water away from it naturally, then cover the top part with soil..is this feasible or just a dumd idea??
The sides just aren't good for supporting dirt as they are just sheet metal. Even though corrugated they just aren't strong. They are pretty watertight allready, but a drain is a good idea anyways. If you want to bury it you can dig the hole tight to the size of the container, then set the container in and use it as the form for pouring concrete. If you get the dirt sides 6 inches from the container it will make a strong wall. I would pour the walls first and let harden, then pour the roof in a seperate pour, just to make sure you don't stress the container too much all at once. The problem with all this, is a container is an awfully expensive form to pour concrete with. I read a lot about using them and decided the block walls were just more economical.
 

jontte

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thought so aswell,then I thought about humidity also, that has to gone also..a nice thought,but those blocks seem to be better, thanks for your advice and thoughts :)
 

Brent S

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thought so aswell,then I thought about humidity also, that has to gone also..a nice thought,but those blocks seem to be better, thanks for your advice and thoughts :)
I think the container would be better for moisture control, but depending on conditions it could condensate on the inside walls. With the block you need to seal the inside with a good sealer like drylock. (that's just a brand of many different concrete moisture barrier products).
 

Akingu

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For a concrete roof over a cargo container, we've used heavy duty corrugated and primed steel corrugated sheeting over a steel frame and edges sealed with a waterproof caulk. The steel is strong enough to hold a 6" slab of concrete. The corners of cargo containers are the strongest joints and any support posts should be welded there.
Another suggestion for underground shelters, irregardless of usage should be either a fan for circulation or a dehumidifier. Mold will be the biggest threat in any underground bunker.
 

Brent S

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For a concrete roof over a cargo container, we've used heavy duty corrugated and primed steel corrugated sheeting over a steel frame and edges sealed with a waterproof caulk. The steel is strong enough to hold a 6" slab of concrete. The corners of cargo containers are the strongest joints and any support posts should be welded there.
Another suggestion for underground shelters, irregardless of usage should be either a fan for circulation or a dehumidifier. Mold will be the biggest threat in any underground bunker.
I agree that some ventilation is a good idea. If it can't breathe it will mold. I'm still working on salvaged materials I can make my ventilation and escape hatch with. It will be part of the roof pour, which hopefully won't be too long off.
 

jontte

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mold is good when you cultivate mushrooms, any other circumstanses I don't wan't to see mold ;)
this forum do give you great ideas..
 

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I would suggest finding an aegis microbe sheild applicator in your area to treat all surfaces. It's invisible, harmless, and very effective (I just applied it at a paper mill about an hour ago).

It will covalently bond to anything and nothing can grow on it - no matter what the conditions are.
 

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