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51K views 51 replies 29 participants last post by  Viking 
#1 ·
Thinking about building a underground shelter. I am finding conflicting information on the lateral strength of cinder-block walls filled with cement and reinforced with re-bar. If there are any structural engineers out there I could use some help. I don't want these walls moving in laterally when the structure is back filled and covered. I want to go down at least eight feet, I would prefer 16 but I need to find out what exactly is down there before I start digging.
 
#2 ·
Well, I'm certainly not an engineer and will not give any advice.

These guys sell books on concrete masonry basement building : Concrete Masonry Publications - CMACN Online Bookstore

Maybe this e-book can help, I don't know if you can get it from other sources though :
Wood-Frame House Construction #73 free download - free download online.

Maybe one of the e-books listed here, again I haven't checked the other sources to get them : Scribd

I can give you personal experience though: my house is built on top of a cinder blocks basement. The structure is in place for 40+ years and still is OK. I live in Canada, where temperature drop below -22 F (-30 C) many times every winter. The concrete slab of my house has been built below the water table level and thus the slab and the blocks are always damp. Part of the house is surrounded by soil and is only 10 feet away from a street where fully loaded trucks pass many times every day. The blocks are filled with cement and reinforced with rebars. The blocks sit on the concrete slab, which top is 8 feet below ground level.

Only problem: joints (mortar) that needs to be repaired quite often. This is due to the water table level problem. I must specify that I didn't built this house. I would have installed a French drain + an elastomeric waterproofing membrane on the blocks (I plan to fix that at one point...).
 
#3 ·
Thanks zorro, that's good to hear. Sounds like well sealed reinforced filled blocks will work just fine. all I need now is blocks and LOTS of re-bar. my only other concern is pouring the floor and ceiling slabs. I almost guarantee I will not be able to do it in one pour and I'm sure as hell not having a truck deliver it. The last thing I need is a lot of questions and a noisy county building inspector showing up. "This is a mighty deep hole ya gots here son... Ya'll gots permit for this here bomb shelter?"
:gaah:
 
#5 ·
:D Oh, then I hope you don't have nice neighbors like mine, who seem to notice every single detail of my life, except when someone cut my garage door heavy padlock and throw everything around in there! :cry: I'm sure they would call the municipal inspector if I'd be digging anything bigger than a 45 gallons drum.

You might still want to read about what makes a building resistant to most external factors (which includes earthquakes, strong winds and such). This is discussed in any building engineering book you may find at the nearest public library. Also, there are many e-books and website describing how to build an underground shelter.
 
#6 ·
Zorro, it sounds like you have neighbors like mine. They seem to watch everything that I do and if they feel like I might be slightly out of line, they call in the bylaw officers. But, if someone tries to break into my vehicle or steal something from my yard, no-one ever sees what happens.

Note: Out-of-line can include parking my vehicle on my lawn in the front of the house to unload groceries or supplies. Out-of-line can include not having my grass trimmed to their specifications. Out-of-line can include dog-sitting while a friend is out of town for a couple of weeks and not having a Calgary-dog-licence even if the dog is registered in another city.
 
#7 ·
Zorro I have read some of your other posts. If I ever loos my mind and start considering it remind me never to move to Canada.:(
 
#9 ·
the most recent thing I've found scouring the internet is some classic pdf detailing how to make one out of wood and dirt.

One thing I've heard is that 10' is the maximum distance between supports or the weight of the concrete will eventually cause it to collapse. Especially if is very deep underground. But this seems like it would make for a very awkward living space.

I like the container wine cellar, but if you were looking for something a little more comfortable for emergency living, would it be possible to connect containers? of course then you have a house made of hallways and I guess that isn't any less awkward.

Time to find some natural caves :p
 
#10 ·
Zorro got love those nosey neighbors:D Thank goodness I dont have any like that. We live in a very small neighborhood on the edge of it. So that a plus. I have great neighbors we all get along great. Never had any problems even with all my late night **** hunting.:eek: Comen home late at night with my hounds or skinning rack with animals on them or my homemade shooting range down behind my house were I shoot sometimes. Were all pretty tight nit around here. With the exception of a few odd balls. No one would bother wondering what was going on if I was digging a bunker. We all joked around before bout building one connecting are properties and running it out to the canel in the woods before.
 
#11 ·
I have a hill in the backyard, and I've virtually covered one 20' container up and using it as a root cellar,
The second one sits a little further exposed, and still uses the regular double doors as entry way.
The second is the 'Projects' and building storage for tools, ect.

I put floor drains in mine,
Coated the outside with basement sealer, and pushed them back into holes dug into the hillside and covered them up.

Works very well for me, but I sure didn't spend $12,000+ on them!
 
#13 ·
that why i will never again live where there are h.o.a. in my book there are nothing but a bunch of old women who have nothing better to do than get into everyone life and become a problem with there little stupid ways of life..

that why i tell one person never live where a hoa is for they are not worth the money in my book..
 
#14 ·
The neighbors down the road build a 'Root Cellar' out of old truck tires.
Got paid to haul them off!

Rammed earth in them for walls, and it works VERY well.
Not sure what he used for roof, looks like wooden beams and tin on the inside.

If I had it to do over again, I'd put pitch to the doors in mine instead of elaborate floor drains.
They were kind of a pain in the butt to do, but I was thinking 'Shelter' instead of storage, and I put a crapper & shower in one so I could stay out there while in the early stages of building.
That mind set kind of stayed with me when doing the second one we now use as food storage.

Pitch towards the door would have been plenty...

I wouldn't put a DESCENDING ramp into it either, it's a pain to keep clear of leaves, snow, ect.
 
#16 ·
questor, These are good Ideas but the containers only cost between $500.00 and $2000.00 also these raise questions and draw unwanted attention.
 
#17 ·
mine are buried.
No one asked any questions.
anymore than, one day you have containers and the next day they're gone.
I have more than 2000 sq ft of usable space.
and you wouldn't know it's there.
metal rusts.
what are you using for an entry way?

also the right location counts for a LOT in my book
 
#18 ·
Goin that deep I'd use arched ceilin, will stand upta the weight lots better. Besure an have a drainage system all around it.

I'd maybe build the walls with block set crosswise two wide say ever 4 ta 6 feet formin a T all the way around ta help stop any shiftin.

I ain't a engineer but seen some stuff built deep before an thats how they do it. Also, Pour the floor first an put rerod er large bolts in it where the block meets, better yet, use say 4 foor rerod up inta yer block, then rerod them tagether an fill with cement.
 
#19 ·
as far as metal rusting ..there is diff coatings you can use ..line-x-is the top of the line in my book ..along with sherman willains tar paint to coat the outside the metal before you burie the tank ..

plus good wide drainage field around the area it design to help keep the water that does come down away from the top to the bottom into the drain field around the metal building ..
 
#20 ·
that's why I went with the monolithic domes.
once I found a location that suited my needs it took a minimum of work to clear the area (5 days). Put in drainage and foundation (about 5 days).
install the domes (2 weeks). cover the whole thing up (a week)
The house took a little longer as it was stick built. The shop is a Steel building.
total cost for the storm cellar $32,000 materials and labor, split 5 ways.
We do have containers . . .as garden sheds and tool storage and such.
We even use three (a 30 and two 20) side by side by side for an "Office/Game room.

I have a friend, in Washington, that lives in 16 containers that (he claims) go down 5 levels. I do know they go up 3 and down at least 3.
He told me that he started getting leakage problems after about 5 years in the deeper ones and one, that was off by it's self, collapsed after a year with only 6 feet of earth on top. It seems all the support is only in the corners where the containers stack on top of one another. He owned a RinoLiner franchise.
He had to sand blast each one that was going to be coated. otherwise it don't stick correctly.
 
#21 ·
first off is containers are a bad idea to try as a shelter even with a semi arched top over the container top unit along with tring to bury it with dirt and even a semi modications on the top to support it ..it better go with a product like monilithic domes or raduis defense or utah shelter companys to be building underground system or a more squared building like the american bomb shelter company

second off drainage has to be done right the first time and not trying to redone at a later date..

third .. ..rinoliner is a not a good product in my book.i done a lot of research on the line -x- product line and found it in my own personal opinion it a better product than rinoliner
 
#23 ·
We use shipping containers for bunker systems all the time. The key is to flip the container over. The roofs are not designed to support weight except at the corners. The floors however support tons and tons. When we flip a container it generally has 3-4 of earth above it to be able to withstand a direct 107mm rocket or 81mm mortars. The insides are reinforced just as a precaution. I have seen a few we have done without the center reinforcement and the ceiling (the floor) looks great.
 
#24 ·
If you look around a bit you may find the cast concrete blocks that act as forms. Very similar to the foam blocks. That would be stonger and still allow for DIY. The foam concrete form blocks would be stong enough once filled also, I just wonder about the water proofing if the foam surface.
 
#26 ·
Yes in this area water is only six feet down. But I am only STATIONED here I retire before long and that's when I will build.
 
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