As if it isn’t enough to have to consider all of the nasty possibilities that may necessitate a retreat to your shelter, in the interest of being fully prepared it’s also important to have a defensive plan in place. Whether the reason for your retreat is a severe storm or complete societal collapse, desperation may bring out the worst in others and require you to defend the safe haven that you’ve built for your family. Stocking weaponry is a start, but a safer bet is to incorporate defensive measures into the actual structure of your shelter.
Entanglements & Barriers
Entanglements and/or barriers may be indicated if you anticipate that someone with ill intent will attempt to reach your shelter. Entrance to your shelter can be effectively blocked with a barbed-wire entanglement: the messier and more “organic” the tangles, the better. Test the effectiveness of your entanglement by determining whether you can get through it. If you have the time and the property for it, thorns and brambles are very useful natural entanglements that can be cultivated over time and can be grown so thick as to be nearly impossible to penetrate. Thick natural entanglements such as blackberry bushes also provide the advantage of concealment.
If you have determined that there is a significant possibility of being attacked, you may also consider a barrier. Bollards (such as the stout posts you see at the entrances to some businesses) can be strategically placed to stop and/or direct the flow of traffic in and out of your shelter and the surrounding area. Any concrete object placed in such a manner as to stop vehicle traffic can serve as a bollard.
Built-in Defensive Positions
It’s wise to put some thought into defensive fighting positions that can be built into your shelter area before you begin construction. These positions should be on the perimeter of the shelter, and should provide a good vantage point for observing an approaching attacker. This can be as simple as a hole dug to armpit depth, wide enough for two people to move around within. Surrounding the perimeter of the hole with 12-18” of dirt will provide natural cover. You can then consider additions such as sandbags or metal drums for extra cover and foliage for camouflage.
Concealment & Escape Routes
If you’ve assessed the likelihood of a threat to your shelter and conclude that it does indeed warrant incorporating defensive positions and entanglements into the design, one of your first lines of defense will be concealment; ideally your entanglements and defensive positions will never be necessary. Considerations for concealment include keeping all structures to the lowest possible profile, covering your shelter with natural canopy and concealing as much of the structure with native plants as you can. If you can, conceal the entrance from a direct line of sight (behind a hill or in a natural depression). Avoid bringing vehicles near enough to leave tell-tale tracks or using the same foot path over and over.
Escape routes built in to the area can take the form of a well-camouflaged crawl trench or, for ultimate concealment, a tunnel constructed from a plastic drainpipe or metal culvert pipe. Escape route exits should be well concealed with foliage to prevent the likelihood of an ambush: you can use old pallets to brace the walls of a trench and then line the top with netting and interwoven foliage or even cover the top with plywood and then enough earth to render your escape route practically invisible.