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Underground Cinder Block Storage

53K views 53 replies 35 participants last post by  djshadow21922 
#1 ·
Morning All,

I was trying to figure out if this would be the best place to post this and thought it would be better so then any place else because of the often talk about bunkers and such. My question isn't so much nuclear related, it's more like mold and flooding related.

I am thinking about building an underground food storage using mortar and cinder blocks. However I don't want to have to live in a desert climate to build something like this and not have to worry about too much moisture in my cinder block cellar. My ideal location would be Wyoming, Montana, Colorado or Idaho. Since it snows in the winter and the ground is quite wet in the spring and such, I am wondering about the feasibility of the long term survival of the building in using cinder block. Can cinder block erode away over time if the conditions are not properly dry? Would one have to worry about flooding through the cinder block?? Of course I know better then the build something like this below or close to the water table. So a High Location will reduce chances of flooding dramatically.

My thoughts are to build a small building under ground and make it level as possible, I thought about slanting it to help combat any adverse water problems but don't really want to do that. The roof would be constructed out of T Iron Supports and Stainless Steel Plates (if not prohibitively expensive). And I would have the entrance be through the roof of course. The Depth would be about 8 ft and the roof would be level to just below the frost line. At first I wasn't going to do this, I was going to put roof to just below grass root level until I remembered the climate I was thinking about building this in.

The other option I thought of would be to use rebar and concrete for everything except roofing once again, but would cinder block be cheaper?
 
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#2 ·
You might find an old pool liner, put it down first as a vapor barrier. It is a lot thicker than say 6 mil plastic, and you can lay block, pour forms and such, as long as you are careful not to puncture. I saw an ad in craigs list for an old pond liner, that may work as well. Good luck and let us know how you do.
 
#4 ·
You can build something like the pic here and then cover it with dirt to make it look like part of the hill, but before covering with dirt wrap it in plastic membrane to control the humidity, we have several in my property.
Then we plant wild shrubs and grasses all over it, you have to be 5 feet from it to see it.
 

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#5 ·
radiation travels in a straight line or in the dust.. meaning you should make it a L shape.. more protection that way.. other then dust getting in thats the only other problem.. (dust contaminated by radative partacles)

I learned about radiation and its effects in grade school.. helps that my dad fixed xray equipment so I had an old x ray tube to show and x rays..
 
#7 ·
here was something i had looked at doing for the entance of the home was to make it look nice along beening part of the hill .. i did look the land over and went with the system that was diff than in the picture ..

when i design the entance and stageing area for the trash can and the shelter electric and freshwater and black water and sat tv lines into and out of the shelter entance .. i went over diff looks and design from the aussa type bush fire shelter design to the tornada and other bad weather design to ww.2. shelter entances and gates units to secured the entance ..so i tried to make the entance as basic a area to come into get the mud or dirt off you feet ..along with the trash can set up that can be wheeled out and dumped as need ..plus design to hold the basic 30 days of trash before need to be dumped ..the second chamber has a area to ditch the partol gear on pegs before going down into the shelter stairwell to the shelter it self .. ..

but here is a few design ideas for the entance in a hillside entance .i took them from my saved photos of the entances area i was looking at doing to the first entance in the home and then down into the tank home entance combo mud room and stowage area for the home before going down into the shelter propler ..

the first design is great for a bad weather shelter but as nbc shelter i am not really likeing it for it was to exposed in the area ..it lets people know there is a shelter in the area.

the second design is a ww.2 school bunker entance with a steel cage to protect the people inside and to lock out the people from comeing into the bunker to play around.. the design would work great on the doors from the other side of the entance where the person could shut the door on the entance and then swing the unit over the door and sealing the door off from a person trying to enter the shelter after the door was sealed to protect the people inside as a layer of protection beside firearms and other unit ..do this in layers and it make the people trying to get inside the shelter to work harder trying to get you along with giveing people a more time to deal with the problem ..

the third design is a down under ausa fire bunker entance design i like the way it fited into the hillside and work as part of the landscape ...to me that has a better chance of beening hidden by putting a trap door system over the unit entance to hide the door ..

the fourth design is from the drawing of a down under ausa fire bunker design with the twin doors and round fire bunker if the downs with redesign with a two 90.dregee turns and a some basic redesign of the shelter it would make a great little home nbc warfare bunker unit ..
 

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#8 ·
When I built my basement I had the blocks coated with a spray on rubber membrane on the outside.
Then I put 2 inches of pink foam over that.
I also put 8 mil poly and 2 inches of pink foam under the floors and put hot water heat tubes in the floors also.
It stays at a very constant temperature all year around and dry.
I think the blue foam is better from what I read for floors because it has more compressive strength.
6 years and still ok knock on wood (my head maybe).
 
#9 ·
Build it then have it sprayed with line-x or something similar. The military has used line-x sprayed cinder blocks bunkers. The are water proof, and in most cases bomb proof. When a normal explosion takes out a bunker, a sprayed one is held together by the line-x. I dont think i would try it, but i shave seen clips before. Any brand (some are mobil companies) should repel the moisture.
 
#10 ·
You need to research the water table. If you don't, you will soon have an underground water tank. In those states you mention, it's probably well underground, but not in all places. There are plenty of bogs in Colorado.
 
#12 ·
my grandparents have a root cellar on their house (Ohio, built in the '50's), the walls of the entire basment are concrete/cinder block, they are painted on the inside with a concrete paint, the outside is whatever it is they do for basements. The floor is concrete. She keeps canned goods, paper towels, etc., etc., etc., etc. in there and never had a problem with mold, mildew.
 
#13 ·
Roof for underground cinder block bldg

I was looking for the answer to cryptkeeper's question to Hawkeye Alex regarding how he poured the roof but not able to find a response ... if there is one can you re-post and if there's not one can you provide best method found? We're going to build larger than food storage and not sure what the best materials and process should be. Any and all responses welcome.
Thanks !!
 
#14 ·
In 1972, I built a 12' X 18' x8' deep cellar into the side of a hill, dug out, poured a 8" footer 18" wide, layed CONCRETE block for the walls , poured concrete floor part way up on the first row of block. Put morter 1"-1.5" on the outside walls and then a heavy coating of roofing tar, with a 4" footer drain. Also put morter on the inside walls at least 1" thick. Bought swimming pool sealer called " Theroug-seal "? spelling. It come in a power and mix with water and brush on with a large stiff brush. Color is light blue or light green. used 2x4, 4x4's around the inside walls to support a 1" wooden board top on the inside of the bock and formed around the top outside walls and used rebar and poured a 4" concrete flat roof, before I poured, layed down tar paper. Back filled with dirt, with gravel against the wall so ground water can drain down to the footer drain easy. Then I built a workshop building on top. Today it still looks new and is dry and cool. Hope I said all of that good enough to understand. Pops
 
#16 ·
I'd like to ask a question that is somewhat related, and I don't know where else to go with it.
I have a home built in 1920 and the windows in the basement are crap, for heating reasons and security reasons....mostly worried about security now but especially now that we are filling our basement with preps. I want to replace the windows with cinder block. I don't know if I can just place cinder blocks and mortar in there or if I need some sort of bar, like re-bar or something connecting the new block to the surrounding blocks?
 
#20 ·
what fitfortrip said. also make sure whatever was in the window is completely removed to expose the bare concrete of the cinderblock so the mortar adheres betterer. mortar doesnt stick too well to painted things.

ive seen people do the opposite of what you want to do, making windows into concrete block walls. more often than not after a period of time the blocks at the top of the new opening separate and fall out. its very entertaining to witness. especially when the opening is filled with a large A/C unit which comes tumbling down from the 2nd story of a building along with a cinderblock.
 
#23 ·
even if you used lightweight concrete like what is used in floor decking for highrise construction you will need to either use pressure treated wood or metal decking as a sub roofing deck or precast it with a lot of rebar and wire mesh and pick it up in one piece and set it in place. (can you say crane?) You can use galvanized steel roof decking supported by a few steel beams and pour a relatively thin 2"-3" slab on it it act as your roof. Just remember that concrete and dirt are HEAVY and if it should fail while you or your loved ones are in it,...well enough said...
 
#22 ·
you can get a purpose made waterproofing for concrete and cinder block construction that is kind of like henry's roof cement. You put it on the exterior of the wall with a roller and when dry place a protective foam board over it to keep it from getting damaged while backfilling. Put a four inch perforated pipe around the perimeter of the structure with about a foot of 3/4 - 1 inch rock above and below the pipe then backfill with dirt. If I were you I would put rebar in every third cell vertically and every second course horizontally and solid grout the block with mortar mix before backfilling to help support the weight of the backfilled material. Dirt is about a ton to ton and a half per cubic yard (27 cubic feet). You need to be careful in order to not fracture the wall.
 
#27 ·
You could leave the windows in and still put in glass block so you can have light in your basement during daylight hours...Also run thick rebar in your window well which will give you even more security....I don't like to loose the light and it would still be very secure....
 
#31 ·
My thoughts are to build a small building under ground and make it level as possible, I thought about slanting it to help combat any adverse water problems but don't really want to do that. The roof would be constructed out of T Iron Supports and Stainless Steel Plates (if not prohibitively expensive). And I would have the entrance be through the roof of course. The Depth would be about 8 ft and the roof would be level to just below the frost line. At first I wasn't going to do this, I was going to put roof to just below grass root level until I remembered the climate I was thinking about building this in.
For most soil types, you need to add steel reinforcement and concrete or mortar filling to the hollow parts of the cinderblocks for any depths of over 6-8 feet. The deeper you go, the higher the earth pressures on the walls are.
For depths of over 8 feet, reinforced concrete is usually the best option.

Only the base of the structure needs to be below the frost line. As long as the foundation is below the frost line, you won't get frost heave damage.

Find out the level of the water table in the area. Any sections below the water table need to be extensively waterproofed, or you can dig a larger hole and provide drainage, which effectively lowers the water table. Portions above the water table will do fine with just damp-proofing.
(The difference between waterproofing and damp-proofing is that damp-proofing will not stop water under pressure. If any constant water pressure is applied to damp-proofing, it will leak.)

If the base of the structure is below the water table, the floor will be subject to upwards force, because the water will push at it from below. The floor needs to be reinforced in this situation.
 
#32 ·
Underground cinderblock structure plans

Hey everyone,
After a lot of looking online I came accross this site, it is the best I have yet to find so I wanted to share with everyone. My shelter will be wider than 8 feet so I am wondering how thick the I-beams should be, I don't want to pour more than ten inches of concrete and the beams obviously have to be encased in the concrete. I am still figuring out the details for my custom job, I will be posting many pics of my project, now if it would only warm up here in New York :)

http://www.americanbombshelter.com/manuals/ASR-bomb-fallout-shelter-kit.pdf

http://www.americanbombshelter.com/
 
#33 ·
fitfortrip,
Those are some good links you posted. I'm looking forward to updates from you. I'm working on the engineering for my own storage space. I've done some very basic designs while working for a heavy construction company, including assisting in falsework design for pouring concrete decks for large maritime shipping wharves/docks but nothing of this caliber. The level of red tape in my area of N. California is astronomical and prohibitive, so it has to be a secret squirrel operation. Moving is not an option and this location will not be sold within 30yrs.

Basic concept:
-Storage room with potential as fallout shelter for 5 people ~10days
-20'x20' interior space w/6' headroom.
-A lot will be taken from the ASR manual:
http://tinyurl.com/3w8kywy
-6"-18" of sandy clay soil overburden on roof (~100psf/CF)
-Reinforced concrete slab floor
-Grouted CMU walls
-Reinforced concrete roof with steel decking, I-beams, steel vert posts.
-Small 4'Tx3'W steel door
-Small manhole access overhead
-Water, electric lines
-Air vent

Completed so far:
-Cut 24'x24' pad into a 20* sloped hillside with skid-steer. Ground psi very high: decomposed granite-- lots of sparks using a pick + skid steer toothed bucket. Dirt walls are "A" rated for high compactness/cohesion.
-Dug 16"Dx16"W perimeter trench footing.
-Grade & compact site
-Pour 16"D x 16"W perimeter footing 24'sq w/#5 bars running in trench
-Pour 6"D 3500-4000psi concrete slab with #5 bars, 24"OC each way
[13.5CY@$80/CY delivered for slab+footing]
Note: Do to a few time and budget limitations I had to work with, I can only have the top of the roof 8' tall at the back and 5' tall at the front. This has to blend in with the hillside profile when I'm done back-filling. The back 2/3 (300SF) will be 8', then slope down to 5' (100SF) at the front 1/3 of the room.

Next up:
-Electrical grounding spike tied into slab rebar
-Layout base course of 8"x8"x16" CMU walls, drill & install 4'L vertical #5 bar reinforcement spaced every 3rd CMU cavity (~16"OC).
-Build base course: 8"x8"x16" CMU bond beam w/1ea #5 bar running length of channel.
-Bond beams every other layer of the walls
-Build up each of the CMU corners, then complete walls [~600 blocks]
-Install vertical #5 reinforcement bars 32" OC (think it's sufficient?)
-Fill walls with grout
-Place 8"x16"x1/2"PL steel I-beam bearing plates with anchors onto top course before grout sets.
-Place 21'L ~W12X? steel I-beams, resting on bearing plates [beam weight per foot TBD, maybe 40lbs/ft]
-Steel columns bolted to floor at center span of each beam.
[Column specs TBD]
-#9 bars 12"OC ea way for roof
-Form & pour concrete roof
-Doors installed
-waterproofing, exterior perimeter drain pipe, vapor barrier
-Back-fill first 12" of exterior perimeter with 1/2" drain rock, then fill dirt
-Interior air venting, lighting, electrical, shelving, water tank

According to the plans in your links, they pour a roof slab the full thickness of the I-beams. I'd prefer to skin over the i-beams with corrugated steel decking and pour a 5"D #9 bar reinforced topping slab, but I fear that would be fundamentally different engineering. Encasing the i-beams in concrete has to have an effect on deflection and other properties. A 21.3'x21.3'x1' slab is over 16CY [~2,400lbs/$1300]. The quote I got for 400SF of steel decking was $1400 delivered, so I guess going with a 12" slab is ~$500 cheaper. Money is a huge issue, I foolishly thought I could build a solid shelter for $5k in material and didn't even have a plan when I started digging. Now trying to keep it under $10k. The pricing in the ASR link shows this size to be somewhere around $90k with labor. I'm not having a P.E. look it over, so I want to to be overbuilt. With 18"+ of clay overburden, we're talking ~75,000lbs on the structure!

I'm looking for input from anyone willing to offer it.
 
#40 ·
According to the plans in your links, they pour a roof slab the full thickness of the I-beams. I'd prefer to skin over the i-beams with corrugated steel decking and pour a 5"D #9 bar reinforced topping slab, but I fear that would be fundamentally different engineering. Encasing the i-beams in concrete has to have an effect on deflection and other properties. A 21.3'x21.3'x1' slab is over 16CY [~2,400lbs/$1300]. The quote I got for 400SF of steel decking was $1400 delivered, so I guess going with a 12" slab is ~$500 cheaper. Money is a huge issue, I foolishly thought I could build a solid shelter for $5k in material and didn't even have a plan when I started digging. Now trying to keep it under $10k. The pricing in the ASR link shows this size to be somewhere around $90k with labor. I'm not having a P.E. look it over, so I want to to be overbuilt. With 18"+ of clay overburden, we're talking ~75,000lbs on the structure!

I'm looking for input from anyone willing to offer it.
if youre going to spend this much time, effort, and money on something you should get an engineer to glance over your ideas. the 5" thick concrete roof with #9 rebar is a bit of a concern for my minimal construction experience. i would say absolute MINIMUM of 6" of 4000 or 6000 psi concrete with #5 rebar set on 12" centers. this would be a roof with minimal/no load from anything above it...like dirt, vehicles, etc.

im not quite getting what youre saying about I-beams and steel decking but using steel underground is a bad idea when steel-reinforced concrete is more than adequate.
 
#35 · (Edited)
Hey everyone, I started my shelter finally, I is 7' x 15'. and 10' deep. I would have liked it to be bigger, but my backhoe would only dig and reach this far. I have many pictures coming soon. I can help anyone if they have any questions about what I did. Keep checking back to see pics.

I can't believe how hard it is to put pictures on here, so we will have to go with out. Sorry everyone.
 
#36 ·
Tahoerdr,

Sweet shelter, way more intense than what I am getting into. I am jealous. :), I hear you on the budget thing, my shelter is only 7x15 and I am in $900 already and only have the footer poured. OUCH.... I went way over kill on the footer, 16 wide by 20 deep, mainly because of my less than professional backhoe operation. All in all I have about 1600 into the project. I have all the cinderblock on site already, and about 10 bags of motar to get me started. Now I am waiting for some decent weather, it will be a miracle if I get the walls done before it starts snowing here....New York. Good luck with everything bud.
 
#39 ·
Tahoerdr,
I went way over kill on the footer, 16 wide by 20 deep, mainly because of my less than professional backhoe operation. All in all I have about 1600 into the project. I have all the cinderblock on site already, and about 10 bags of motar to get me started. Now I am waiting for some decent weather, it will be a miracle if I get the walls done before it starts snowing here....New York. Good luck with everything bud.
a 16"x20" footer for an 8x8x16 block wall isnt overkill. codes in my area dictate a 16"x16" footer...and we dont have to worry about freezes
 
#37 ·
You talk like you haven't picked your site yet.

If I was planning Beaucoup underground additions, I would want my house no more than half the way down a good sized hill.

Water ain't gonna pool too much inside a hillside, and the water will be more or less standing in line, awaiting its turn to slowly percolate downhill.....

Not that I'd leave out any other of the Waterproofing Measures.....


......RVM45 :cool::eek::cool:
 
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