The Meme of Crushroom: A Key Retreat Architecture Element

One bit of retreat architecture that I’ve often recommended to my consulting clients who are designing (or retrofitting) retreats is the inclusion of a protruding entryway foyer, that I call a crushroom. Passing this advice along to you gives me the chance to employ one of my horrible puns: The Meme of Crushroom. A crushroom is a controllable confined space, typically an entry foyer, that can be covered with small arms fire or subjected to irritant or obscurant smoke or sprays. The outer door (or barred gate) to the crushroom is normally left open, but has a spring loaded self -closure device, and an automatically-engaged remote-controlled lock release mechanism. Think of it as a box trap for Bad Guys. Have you ever visited a Big City apartment with a communal door where you need to get “buzzed in”? In this case, the Bad Guys will have to be buzzed out of your crushroom

The home invasion threat can only be expected to increase in coming years. I anticipate greater use of dynamic-entry tools by home invaders. For instance, they will soon use commercial or improvised door-entry battering rams and Hallagan tools—like those used by firemen and police entry teams. This means that standard solid-core doors by themselves will be insufficient. In a worst, case, thugs might even use vehicle-mounted battering rams. In such circumstances, it will be wise to have the extra layer of protection afforded by a crushroom.

You should position the outer door to your crushroom one of its side walls, rather than lined up with the entrance door to the house. Having this 90-degree turn and allowing just a four foot space in front of the house entrance door has several advantages: First. it makes it impossible to use a long battering ram–since it limits the length and “throw” of a battering ram. (Even a very stout door, hinges, and doorframe will not withstand the impact of a 10-foot-long battering ram that is manned by a team of thugs). Second, it removes direct line of sight into your house. This is useful for light discipline, in a grid-down situation. (When you are likely to have electric lights in your house interior, but your neighbors won’t.) Lastly, the crushroom wall opposite your front door provides another layer of ballistic protection–it would have to be knocked down before your front door could be attacked.

Picture this: With your intrusion detection security system, you see one or more thugs approach your house. They are acting “hinkey”, or outright aggressive–perhaps rushing in to conduct a home invasion robbery. Then they proceed to try to kick down your front door. But lo and behold, they don’t succeed, because you’ve built your door and barred it to Rawles specifications. (Strong enough to resist even a small battering ram, and armored against small arms fire.) Using your intercom-loudspeaker, you sternly warn them away. But since they have bravado to spare and have never before encountered a door that they couldn’t kick in, they persist with their futile leg exercises. At that point, you already have your telephone in hand, and have dialed 911. (That is assuming your are in pre-Schumeresque circumstances, when there still is a police or sheriff’s department willing and able to respond.) You then flip the switch, releasing the crushroom’s outer door. It slams shut, and locks. Now, the thugs feel trapped, crowded, or crushed in the close confines of the foyer. They will then almost surely turn their attention to kicking at the outer door (or barred gate). At this juncture, you have several “continuum of force” options:

A.) You shout a stern warning and then hit the switch releasing the outer door and “buzz them out.” This is effectively just letting them go, with a warning. Such a course of action is recommended only in current day “peaceful” circumstances.

B.) Using your exterior loudspeaker, you spend five minutes sharing the Gospel with the thugs, then you hit the switch to release the outer door.

C.) You pull a wire that is attached to the pin on a smoke grenade in the decorative “overhead light fixture” in the foyer, and simultaneously start playing your retreat’s PSYOPS tape over your exterior loudspeaker, at around 60 decibels. This combination (especially a violet smoke grenade and a tape of Jimi Hendrix playing Purple Haze) is sure to make the thugs think twice about coming back.

D.) You pull a wire on that is attached to the pin on a CS tear gas grenade, and simultaneously start playing your retreat’s PSYOPS tape at around 90 decibels. This, (especially a tape of Credence Clearwater Revival singing Bad Moon Rising) will probably make the goblins soil their trousers and reconsider their life of crime.

E.) You slide open an armored gun port, and protrude the muzzle of your favorite large-caliber lead dispenser.

F.) Any combination of options B, C, D, or E, in whichever sequence seems apropos, given the day’s relative Schumer Index and the prevailing exigency of the circumstances.

Alternatively, your crushroom could normally be kept locked from the outside. This will provide a valuable delay for even the most ambitious dynamic entry by home invaders. It will also provide you a safe place for you take delivery of mail and packages with some “stand-off” distance.

Four Important Provisos:

1.) Only build a crushroom if you are also going to first upgrade your front door and doorframe to very stout specifications, and the surrounding wall is of similarly stout (i.e. masonry) construction. The last thing that you want to experience is a bunch of enraged bad guys actually entering your home.

2.) Do not mention the purpose of your crushroom to friends, neighbors, or even relatives. It should outwardly just look like either a “mud room”, a “weather airlock”, or perhaps a “Spanish style” foyer, with “decorative” heavy wrought iron bars. If you are indiscreet, word of it may get around, and then at best you’ll get labeled as the local survivalist whacko. Or at worst, word will get as far as the local band of goblins, and whilst sharpening their knives they will deviously plan to bypass your crushroom entirely. They may decide to either bushwhack you while you are out splitting wood, or invade your house via your roof, with a chainsaw or a fireman’s metal-cutting rescue saw.

3.) I most strongly encourage readers to use your crushroom’s outer door as a mantrap (and any of the other active measures that I’ve mentioned) only in truly postTEOTWAWKI circumstances. As I’ve noted many times before in SurvivalBlog, we live in an extremely litigious society. Displaying the audacity to actually hold bad guys in place until the gendarmes arrive could be grounds for civil lawsuits (for false arrest, excessive use of force, mental distress, etc.,) and possibly even criminal charges. In essence, if you hold someone in a citizen’s arrest in excess of what a jury of your peers deems justifiable and reasonable, then you could conceivably be charged with felony kidnapping. Here, the “Reasonable Man” standard will probably be applied. (Black’s Law Dictionary defines citizen’s arrest as: “The apprehending or detaining of a person in order to be forthcoming to answer an alleged or suspected crime.” See: ex parte Sherwood, (29 Tex. App. 334, 15 S.W. 812).

4.) Be sure to provide yourself a way out of your crushroom, in the event that the outer door closes unexpectedly when you don’t have a door key in your pocket. Perhaps a spare key that is very well-hidden behind some molding.

For further background, see this letter in the SurvivalBlog archives on “man trap” architectural features.

Some Suggested Suppliers:

Door closing springs. Check your local Yellow Pages for “Fire Door” hardware suppliers. Your local locksmith probably knows of a supplier, or may have a pile of used one in his back room. For a man trap, the faster the action of the door closure, the better. Hence, a traditional coil spring action is preferable to the more modern, slower pneumatically-dampened springs. Think in terms of cattle chute hardware, rather than what you’d likely see on shopping mall doors.

Door release solenoids. (You’ve probably seen these on fire doors at hospitals and other public buildings.) Note that in circumstances where grid power is iffy, you can substitute a mechanical release, activated by a simple pull-cable and cotter pin.

Door lock & release solenoid (“buzzer lock”) mechanisms. Search for local suppliers with a the web search phrases “mantrap” or “common door buzzer lock”. To provide sufficient “hold the goblins in place” strength, you may have to use multiple locking solenoids–at the top, middle, and bottom of the door–that are engaged and disengaged simultaneously.

CS tear gas grenades. These are available from police supply houses. In most states it is not illegal for citizens to possess them. But by their company sales policy, most police supply houses will only sell these to orders placed on police department letterhead. But I’ve occasionally seen gas grenades sold at at gun shows, and they also come up from time to time on firearms auction sites like and For example, see this current GunBroker auction. Be sure to consult your state and local laws before buying these or similar pyrotechnic devices.

Gun Ports. You might luck into some of these at a scrap yard (from a retired bank armored car), but more likely you will have to fabricate these yourself, or have a welding shop make them for you. Remember: Gun ports work both ways, so you will want a thick, well-braced, sliding backing plate that latches securely. Specify everything for the ports very thick and very stout. Any exposed hardware should be large-diameter and welded in place, once assembled.

Exterior (weather resistant) loudspeakers. Rather than buying new (and expensive) speakers, try placing a “wanted” ad in Craigslist. It is amazing to see what people have salted away in their garages and attics.