Letter Re: Using Natural Caves on Private Property

My friend has a piece of property that has a cave. The initial opening to the cave is circular, about four feet in diameter. Inside the cave is a large room with a 20 foot tall ceiling and an approximately 70 foot long floor. We have been inside three additional smaller [side] rooms. Also, we have found a source of water deep in the cave. We spent the night in the cave about two weeks ago. It got cool at night, but no bats or other animals joined us.

The biggest potential problem I can think of is the relatively small opening. However, due to its small size, my friend and his wife walked by the cave hundreds of times before they realized it was an opening.

Would this make a good retreat when the stuff hits the fan?- Linda H.

JWR Replies: Caves do have their uses, particularly as expedient fallout shelters. Finding a cave with an unobtrusive entrance on a piece of privately-owned land that is under your control is very fortunate. I’m surprised that it wasn’t mentioned by the previous owners at the time that your friend bought the property. Keep in mind that caves are far from vermin proof, so you would need to store anything inside in sturdy, waterproof containers. Many caves are seasonally wet, so waterproof containers put up on at least 4×4 wooden blocks are also a must.

The existence of caves is often widely known by locals, so don’t consider anything you store there truly secure. It might be worth your time to make a “rock” door to camouflage the entrance. Start with a wooden framework of 2x2s, covered by doped fiberglass with a highly irregular “hilly” shape. Then prime, coat, and seal it to match any nearby rock outcroppings. There are now some amazing rock texture paints—pioneered by Zolotone–that look quite natural. One of the popular brands is “Roller Rock”, made by Daich Coatings. When applied with a rough-textured roller, these coatings can be very natural looking. These paints can be custom tinted. It is probably best to bring a sample of the local rock to the paint store, and have them match the color)

Before storing anything of value in the cave, leave your camouflaging “rock” door in place for at least a full year, using a telltale. (A twig wedged into the doorjamb–if it has fallen you’ll know that the door was disturbed.) Storing anything in the cave without taking that precaution is an invitation to theft. You might want to set up a Dakota Alert (or similar passive IR intrusion detection system) to see if anyone goes near the cave entrance. If you have welding skills, or you have a trustworthy friend that knows how to weld, then you might want to install a locking steel security door or barred gate back behind your “rock camouflaged” door. Just keep in mind that given enough time, a determined burglar can reduce nearly any barrier. (At this juncture I should mention that I get one or two e-mails a year from readers that have had their CONEXes broken into by thieves with bolt cutters or cutting torches.) But at the very least a locked security door will slow burglars down. It will also tremendously reduce your risk of an attractive nuisance lawsuit.