Concrete shelter building considerations

Concrete shelter building considerations

Are you like me and sometimes play with the idea of having your own bunker mancave, but have to make up some reasons why to build it? Or maybe there are some real-life reasons to build it and you’re gathering some info about things you should consider?

No matter which one the reason is, I’ve done some brainstorming here and tried to put out some information that is relevant to real life. If you see something missing feel free to leave a comment as this is something that would be nice to get perfect.

Now, to move on with shelter building, read on.

Concrete safe room construction

This article is mostly for fun speculation. If you’re serious about building a shelter, I suggest that you contact proper builders. We don’t want the shelter to be an addition to the danger by being too weak. Falling concrete can be deadly so it has to be built with enough reinforcing and proper thickness.

Now, if your area is prone to tornadoes and hurricanes, your home probably already has a shelter where you can make your family stay for a short amount of time. Tornado and hurricane shelters are being built more and more due to the weather conditions changing their patterns over time.

Underground areas and basements work extremely well for this purpose but for homes that have a deeper foundation or are built on a slope, you might have to condition other alternatives.

One thing to consider could be using a home’s interior room that is constructed for withstanding possible damages and high winds. Using concrete for maximum durability and strength is highly advisable.

Underground concrete shelter

Necessities to be considered

Tornado or hurricane shelters need to have just one door and no windows, ideally. All the surrounding structures need to be made of solid concrete. Although shelters only need to be really just big enough to fit the whole family, essentially, the size is absolutely up to your discretion.

If your area has frequent warnings of hurricanes and tornadoes, you will most likely prefer a bigger space for having to spend more time in the shelter. The fact is that hurricanes move very slowly and may force you to be in the shelter for hours at a time.

How to build a concrete safe room ideas

Here are some ideas on how to build a concrete safe room. Ideally, the room has no windows so you don’t have to think about those as they are a weak spot. You can also consider building with polymer concrete, it’s more expensive but really water-resistant and strong.

Safe room doors

Doors need to be tight and strong since doors that are insufficiently made will render everything else useless. The ideal scenario is that the door you use should be able to lock and slide into place instead of operating on hinges.

Doors that are hinged can be sucked by stronger winds and blown away. Doors need to be hard, thick, and with metal reinforcement on each side. When sliding the door into place, it needs to bracket for restraining on the bottom to make sure that this does not sway.

What type of concrete to use for safe room

You need to consider concrete safe room wall thickness before you begin here. You will also need to use reinforcement rods to tie the ceiling, floor, and walls together which extend from one slab of concrete to another.

The poured reinforced concrete is ideal for concrete or hurricane shelters. Bars for reinforcement need to extend into both the ceiling and the floor for major wind resistance.

Tensile strength is also provided by reinforcement to be able to withstand the heavy kinds of objects thrown on the walls where there is weak concrete.

Correctly filled and reinforced block walls need to be used. Hollow block walls will not be able to withstand the major storm forces by themselves. These kinds of block walls need to be reinforced the same way as a poured concrete wall, with the extended rebar going through the ceiling and the floor slabs.

Once the walls have been built, all the cores need to be filled with a mix of concrete pea gravel. This mix is very strong and flows through the wall to fill the gaps. All the walls need to be eight inches deep which is the depth of the blocks of concrete. Ceilings need to be four inches thick.


Ensuring the safety of your family is the main function of a shelter made from concrete. It doesn’t need to be aesthetically pleasing or very apparent, but if you have a small space, your shelter can also sometimes be used as a closet, bathroom, or living room. This would be very convenient if you will need to stay in it for long periods as well.

If the nature of your shelter as a dual living space will compromise your safety or create extra costs, you might decide to use the shelter for other purposes. Make sure that all the plumbing, outlets, and intrusions do not affect the concrete’s integrity. Any glass or wall fixtures need to be secured or removed so that they do not turn into unexpected projectiles in the coming storms.

Also the most important function of all, ventilation. You must ensure that in all situations proper ventilation must be covered. You don’t want yourself or your family suffocating inside a concrete cube. Depending on the catastrophe you are covering, think about how you can ensure proper ventilation in all situations.

Other than that, I can think only about water control. There should be a drain and a proper way to handle water that might be coming in. This would depend a lot on the way it is built so you can find out proper solutions.


The concrete shelter can provide real protection if build correctly. For serious building reasons, like written in the beginning, I would consult professionals to not put my own family in harms way.

Other than that, I think a shelter would make a nice man cave if you’re in need of one. When needed, it could also provide the needed safety. If building a new building and want a basement for this kind of purpose, maybe consider ICF. The extra insulation might be good for times when power is cut off.

It could also act as storage space while it’s not used for this kind of purpose. Do you need space for your tools or other equipment? No problem, use it as a such until it’s needed. It’s easy to build storage space for food, water, etc. in there if everything else is covered as well.

Here is a guide on water tanks if you’re interested in water supplies. It might be a good addition to any shelter if you need to have a water reservoir for a longer time. It could be part of the house and shelter.

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