As I promised in a previous article, I worked out some rough plans for a basement shelter that I want to share with you. If time and resources permit, I may begin work on building this late this Summer, but next year is probably more realistic. Along with being able to afford the project, another concern I have is whether or not I have sufficient space in my basement. If not, I may have to rent a Bobcat or something to excavate a hole to build the thing in my yard.
Before we begin, keep in mind that protection from radiation is achieved through mass. The numbers I have always gone by to achieve protection from 99% of radiation are as follows: Steel – 5″; Concrete – 16″; Earth – 24″ packed or 36″ loose; and, water – 36″.
Being that we are building this shelter in a basement, it is already blessed by having the earth around it and your house above. This effect is multiplied if your house is more than one story; the voids from each floor to each ceiling won’t help you, but the combined mass of the wood and building materials will.
Mortar and a trowel
Bagged quikrete, sand and gravel
Steel or heavy wooden beams
Steel rebar (optional, yet highly recommended for increased strength)
Choose a suitable place for your shelter. I suggest you utilize a corner space as it will give your structure added strength. I also suggest you choose a space with no windows.
Whether or not you imagine you’ll ever find yourself in danger from nuclear radiation, I’m including this next step as a means of added protection against that possibility. That being said, you can skip it if you prefer. Using the drill, screw sections of plywood to the ceiling joists to create something like a shelf in the void between each beam. I suggest screws as they will provide a stronger bond for the construction, but a hammer and nails would suffice. Also, you’ll do it in sections (you’ll need to pre-saw the 8×4 plywood sheets into smaller, more manageable pieces prior to beginning). Once your first row of “shelves” are ready, fill the void as tightly as possible with bricks. If you’ve done it in small sections and used screws on both sides, it will hold the weight. Be sure to fill the void as tightly as possible, always remembering that mass is what stops radiation. Repeat until the ceiling over the entire area you’ll be building your shelter is covered.
This next step is another that you might be able to get away with skipping if you so choose. I consider it wise as a hedge against any possibility of flooding as I plan to store emergency preparedness supplies in my locked shelter year-round. Using whatever means you find most expedient, build a form into which you will pour a concrete foundation that raises the floor of your shelter several inches above the floor of your existing basement. Now is a perfect time to position steel rebar in the wet concrete. The rebar is another part of this you can probably skip, but using it will increase the strength of the finished structure.
Build the walls to your shelter using the concrete blocks, remembering to leave space to install a door as well as a filtered air intake later (you may also want to run electrical or telephone wiring or pipe in water – I’ll leave that to you). If you’ve used the cinder blocks with the voids in them, I advise you to mix up another batch of concrete mix and pour it in the empty spaces so your walls are solid. This will help to increase the protection factor from blast forces, heat, ballistics, et cetera. The height of the walls is up to you, but FYI a wall built 10 blocks high would afford an internal shelter height of 6’8″ and there aren’t many of us who couldn’t make do with that.
The roof of the shelter should be constructed by laying steel or sturdy wooden beams completely across the top of your shelter and packed tightly together. You could conceivably spread them out more and use them as supports for a ceiling of plywood or metal sheeting, but packing them closer reduces void space and thus provides more protection from radiation. You will need to buy or cut these to the correct size. They should be long enough to lie across your structure, resting upon the tops of the walls but not hanging over if it can be helped. Use vertical beams or build block columns at equal intervals within your shelter to provide added support.
At this point, your basic structure is complete. I would advise covering the roof with plastic sheeting to provide a moisture barrier and adding another layer of tightly-packed bricks (no mortar). Beyond that, the more overall mass you can cram into whatever empty space exists between the roof of your shelter and the roof of your basement (which we stuffed with bricks earlier) the more protection you will have from radiation. Continue to add as much as possible, but always be mindful of the weight on your ceiling and its stability.
Paint the whole thing, inside and out and floor to ceiling, with moisture-resistant paint.
I’ve left it up to you to decide certain things on your own, such as ventilation and what kind of door to use and how to construct it. I would strongly suggest a metal door though. And, since you’ve gone this far already, take the tiny extra step to make sure your ventilation system has filters that are rated for NBC protection.
© 2009 Backwoods Industries (except where otherwise cited). Text, video, photographs, and any other material may be republished, rebroadcast or redistributed as long as our website is sited as the author and a link back to our website is provided.