Perimeter Security: Use of an Obstacle Plan

View Latest Activity

Home Forums Tactics & Leadership Patrol and Missions (HEAT 2) Perimeter Security: Use of an Obstacle Plan

  • This topic has 17 replies, 10 voices, and was last updated 1 month ago by AWS18. This post has been viewed 403 times
Viewing 17 reply threads
  • Author
    • #92080

        This article is intended to discuss ‘obstacles’ and their use as an aid to perimeter security. There are a number of factors and considerations regarding perimeter security, which will be discussed here. For specific information on home hardening, you will find some useful articles on such by Joe here on the MVT Forum.

        It is essential to understand that any perimeter security measure that you use will only ever cause delay, by slowing down the ingress of an intruder. It is unlikely that you will be able to install a perimeter security feature that will permanently deny entry to a determined intruder, given sufficient time and determination. This is why in a military sense, any obstacle that is installed should be ‘covered by observation and fire.’ The obstacle is thus simply intended to delay the enemy, in order to be able to bring fire on them, the delay providing time in which to deploy forces to respond, thus regaining the initiative. This is why on the battlefield, obstacle planning and execution is an important engineer task, above and beyond what infantry or ‘assault pioneer’ specialists may do locally around their positions. The obstacle plan will be part of the overall defensive plan, in order to deny, slow, or channel the enemy and thus ‘shape’ the battle space.

        We can apply these principles to an area of property which you may have an interest in defending. You should also read this in tandem with the article ‘A Discussion on Bugging Out‘ for considerations if, worst case, you do get attacked by an overwhelming enemy force. Any area of property that you have will come with natural features; terrain, vegetation, buildings, roads, rivers or streams, and fences. The overall acreage of the property will also be a factor, along with visibility (due to terrain features or lack of, and vegetation (i.e. trees) or lack of). Terrain, along with the relationship of that terrain to the buildings on your property, will create factors of key terrain and vital ground. Vital ground is that ground which, if lost, would make the defense untenable. Key terrain will give one side a marked advantage. For example, it may be that you consider your house vital ground, which it perhaps is if it is on a suitable terrain feature (i.e. a hill). But if it is next to the hill, the hill may dominate it and thus be the vital ground. There may be other features, such as a wooded ridge, that may be an ideal support by fire location onto your vital ground, and as such is key terrain, offering a marked advantage for any side which holds it. This is a somewhat complex topic, which boils down to a defensive survey, which you should conduct with a view to both attacker and defender, and in conjunction with a view to enemy ‘most likely’ and ‘worst case’ courses of action.

        You should assess the property with a view to routes of ingress (i.e. mobility corridors) on to it. There are going to be obvious ones, such as your main driveway, perhaps a secondary road back on to your ‘back forty.’ There will be trails and tracks, and these will also need to be considered in relation to the surrounding property and where they may lead to/from. Terrain itself, considered along with vegetation, will provide natural lines of drift, perhaps along ridgelines or valleys. Are we concerned about accidental incursions onto the property along natural lines of travel, or deliberate incursions perhaps from a certain area assessed as higher risk? The Interstate, a local town or city, etc.? Natural features will also play into this, such as significant water ways, cliffs, broken or marshy / swampy ground, etc. Some of these features, such a waterways, may themselves be used as a mode of transport. This therefore brings us to an assessment of modes of transport, and what routes may be suitable for which. How could people arrive at your property? What is most likely and what is worst case? Vehicles, ATVs, horses, on foot?

        As you start to look at this, you will start to develop a picture of the most likely and least likely means of ingress to the property. You can start to overlay this with an IPB (Intelligence Preparation of the Battlefield) study in order to try to assess which threats are most likely. This of course needs to be constantly updated as the situation develops, as we move from current times to increasing lawlessness and more violent threats. Joe has offered IPB training exercises on the Forum and will likely continue to do so given sufficient interest / engagement (for that, read “lurking is not sufficient”). You must always remember the principles of defense, one of which is ‘all round defense.’ A mistake would be to, for example, focus on threats arriving up your driveway in vehicles and perhaps off the back forty in ATVs, while ignoring other areas because they are suitable for foot movement only. Or perhaps because you wouldn’t want to do it? Never underestimate a determined enemy, and thus do not rely on unobserved obstacles or terrain to keep anyone out. This is why we need to consider observation posts and a patrolling plan. Having said that, the flip side is that “he who defends everywhere, defends nowhere.” Thus, you need to make an assessment and take calculated risks in terms of allocating resources for defense. If you have a patrol plan / plan for running temporary observation points as part of your defensive plan, you are able to allocate resources to priority areas but also swing by the lowest risk points of ingress, and thus keep half an eye on it.

        The above paragraph is something we cover on the Combat Patrol (HEAT 2) class. Always consider that you are under enemy observation. That is a good type of paranoia. You must vary patrol routes / times / patterns in order to stay away from complacency and predictability. If a threat identifies you as a place that has a stash of mountain house in the basement, they will be motivated to come get it. If they resist a plan involving dying in trucks on your front driveway, they may decide to put your place under observation. They will do that from a location where your patrols do not go, and they will identify your patrol routes and patterns. This will factor into their attack plan, how to ingress, establish support by fire, and how to raid your place.

        Having established the natural features of the property, which will be considered in conjunction with permanent man made features that are already there, such as roads, fence lines, buildings etc., you may now want to consider an obstacle plan. The obstacle plan is created in conjunction with the overall defensive plan. For that, you will need to consider what you are defending and the resources that you have to defend it. Your most important, and most scarce, resource is going to be trained shooters. You will use the obstacles to augment the defensive plan and make your limited numbers of fighters go further. Just remember that if an obstacle is not observed, it will only serve to delay or slow down enemy ingress, it will not stop it. Given modern technology, there are a number of things that you can do to help spread your resources – if you can guarantee that it will work in a grid down situation, you can use a combination of ground sensors and cameras in order to place perimeter ingress points under remote observation from a central command post. Even drones are a potential use, to fly the property and send back real-time images. Use what you can, but plan for that now.

        Now that you know the routes (mobility corridors) onto the property, you may consider that you want to deny access to some of them. Remember that if you block a road or a track, you are not denying that zone in entirety as a route of ingress – it may force attackers to dismount vehicles, but probably allows them to still approach on foot. A danger of this is that, thinking the route is ‘denied,’ you fail to focus any attention on it, and are thus taken by surprise. You should also consider your obstacle plan along with any neighbors who may or may not be part of a mutual support plan. Are you planning on moving a force to support them if they are attacked, and they you? Or not, and thus you have no concern to access across to their place? Ways to deny use of a route are limited only by your imagination, supplies, and equipment available. Choices could induce:

        • Security fencing.
        • Barbed wire entanglement / low wire entanglement.
        • Felling trees: creating an ‘abatis’ of entangled felled trees.
        • Moving dirt – creating a berm or digging out the road.
        • Parking vehicles or equipment.

        By doing this, you may be denying a route of ingress to certain transport types, or creating ‘slow-go’ or ‘no-go’ routes. You should also consider that you may not want to permanently deny access to a route. This would be particularly applicable to something like your main access route or driveway. You probably want to block this in some way, to prevent easy or casual access. A simple gate may accomplish this but give consideration to violence outside of what you may usually expect day to day – what if someone just drives a truck through the gate? A way to temporarily deny access to a entrance route is to include a moveable aspect to whatever permanent structure you build up there. Think along the lines of an entry control point (ECP) where you may have obstacles creating a serpentine on the approach, to slow approaching vehicles down. You then have a structure strong enough to deny vehicle breaching, with something like a piece of machinery or a heavy vehicle acting as the ‘gate’ or moveable part, to allow access as desired. It stands to reason that this will need to be moved by one of your people, and that the keys should not be accessible, or the vehicle able to be turned on and moved, by an outsider.

        The above regarding the moveable ‘gate’ leads to the question of whether or not you are planning on manning the ECP. Do you have the manpower? Anyone manning an ECP is also subject to sniper threat, unless they have a suitable ‘guardhouse’ that is protected with cover from view and fire. But if you do not staff it, it is not ultimately a useful obstacle, unless it is under observation and potential fire. Can you view it from your main house? If you intend to cover it from an observation post at the main house, is that a suitable protected fighting position if a firefight ensues? Can you cover the ECP with patrols? Can you observe it remotely by camera or sensor? This leads to the aspect of rules of engagement. You have no idea who may approach your property and for what reason; you need to establish procedures and rules of engagement. If the ECP is manned, then this could be a conversation, having stopped the potential intruder at a safe distance. If it is not manned, do you have signs posted, warning not to enter? Do you perhaps place a field telephone at the ECP with a sign asking people to call if they want to gain admittance? Have you thought about this? Anyone that you involve in protecting an access point must be clear about procedures and rules of engagement, thus keeping the property safe in a morally correct manner, and dispelling any doubt. Predators will take advantage of any doubt, and if you warn them that if they keep coming, they are subject to lethal force, then you better be prepared to do it, or they just called your bluff.

        An alternative to simply attempting to deny access to the property is to use obstacles to shape the area and thus create a ‘channeling’ effect. By doing this, you encourage intruders to come in by a certain route. You deny access in one area, but allow it in another. This could be part of a general ECP security plan, in order to bring people in to a place where you have a good advantage. It could also be done to get the upper hand on obvious hostiles. For example, depending on your terrain, you could use a little subterfuge to make the main driveway to your house look like a clear and inviting route. But deeper in the property, or using some defilade (dead ground) unseen on the initial approach, may be another blocking obstacle. This would allow you to bring hostiles in to a place where you can have established fire positions, a prepared ambush if you will, that you can man once you get early warning of the approach. Note: early warning, meaning that you must have some sort of forward surveillance or alarm, and the trained people to move out in a hurry to man the defensive piston; think having a Quick Reaction Force (QRF).

        In a military sense, and given enough ground, you can assess the terrain and routes of ingress to your defensive position, and designate Named Areas of Interest (NAI) and Target Areas of Interest (TAI). These become part of your surveillance and observation plan and require a forward observation and patrol screen. This would be best done with a larger area of ground, mutual support network of farms, or perhaps a defended village. This allows you to conduct a mobile defense, moving resources to where the threat is – which of course needs a mode of tactical mobility, such as trucks or ATVs. The way it works is that you establish observation onto the assessed NAIs – these being likely routes that attacking forces may use coming in to your protected location, at sufficient standoff to give you time to react and deploy. NAIs will usually involve a decision point (DP) where the enemy may take one or another choice in the route, or the DP could simply be that the enemy is coming in on that one route, with no alternatives. Once identified, and strength assessed, reliable communications will report the DP back to the main location. At this time, the commander will make his decision, which if it is to defend, will involve deploying ambush forces out to the TAI related to the NAI/DP. These should be to prepared ambush positions. Once the ambush is conducted, the forces will fall back through a series of defended positions to the main location. Ideally they will fall back using covering groups so it becomes a leap-frog on larger scale of fire and maneuver. Thus, a cover group in the second ambush position is able to cover the move of the initial ambush group back to the third position, etc.

        Remember that we do not know the exact form that any sort of ‘collapse’ may take. We may face increasing violence in society in a sort of ‘Rhodesian’ manner. We may face a total grid down collapse. Your response will depend on the severity of the situation, and clearly you will not be reaching a point of larger groups coalescing at one individuals’ home or retreat until we reach to more extreme end of the scale. Thus, anything you do must be appropriately ‘camouflaged’ to blend in with the situation. There are things you can do now that will not seem unusual to anyone visiting or delivering at your home. Fencing, gating, grading, creating landscaped fighting positions and covered routes, perhaps planting evergreens to create cover from view etc. If you have more extreme measures in mind, they should be planned for now and you need the equipment to put them into place when the time comes.

        You most important resource will be trained fighters in order to make this defensive obstacle plan viable. This is the most scarce resource and the one that is hardest to create – both getting the right people, and getting them sufficiently trained and working as a team. Most people are kidding themselves, and are often a waste of space. You might find some help here on the MVT Forum for that!

      • #92081

          Joe: can you link to some of your house hardening articles, as well as IPB discussion? Thanks.

        • #92082
          Joe (G.W.N.S.)

            Here is the IPB link (Feel free to start a Thread for any questions)…

            “Your mission should you decide to accept it, build a IPB/Area Study!”

            …I recommend this Thread by Max emphasizing the need.

            Intelligence: The Essential Element

            This link will provide much needed technical information for aspiring engineers.


            Related to above link Concealment does Not equal Cover, Urban Environments.

            As Max states much of this related to buying time.
            Passive Counter CQB: Urban

            I have some more ideas related to the following involving mesh networks.
            Security Surveillance Measures at a Rural Retreat

            Automotive Security Window Film

            Remember this film has use in retrofitting other types of windows.

            There are probably some other links that I’ll add later.

          • #92083

              No questions or follow up on this one? Thoughts, examples, questions about specifics? Have we become a forum of lurkers?

            • #92084

                So for me personally, my assessment is that our current location is untenable for a severe crisis. It would take an immense amount of manpower to restrict avenues of approach (so many!), along with cooperation from many neighbors. Our neighborhood itself is a busy middle class suburban neighborhood but is within a few miles of urban poverty crime centers, you know, like that place Mufasa warns about:

                For low level threats, my plan is to replace some glass-windowed doors and maybe some unwelcoming thorny bushes around windows. Maybe have a spool of barbwire on hand?

                My wife and I have both agreed that this isn’t the long term house/town for us and in 5ish years plan to find something semi-rural (but still commutable). Something where I can’t hear a neighbor sneeze on a nice day with the windows open.

                EDIT: We do actually have some basement window wells that could easily function as fighting positions on one side of the house and a retaining wall running along our back yard for some good cover. Also, a part of our house sticks out in the front with good fields of fire that would be good for hardening with sandbags on the interior. At the end of the day, I don’t think the property is even worth fighting over in a long-term crisis. There’s also a shallow abandoned well pipe in our backyard that could probably be rigged with a pump in a emergency.

              • #92085

                  Thanks for this Max. I can see all but the gate of my original 10 acres on this property from the front porch; I’m not overly visible to anyone driving in, in that location, but there’s no real cover. I’ve since added an RF alarm on the gate and a game camera to let me know I have “company” from the one vehicle-accessible access in here.

                  I think about this topic a LOT, given it’s usually just me here. And I run the mental scenarios – and scout out the terrain from different perspectives – to start to get an idea of how many people I potentially need to secure this place.

                  Now that I’m adding 139 adjoining acres, the problems and thought-process has gotten a LOT bigger. It helps that the add’l acreage is land-locked (except for some types of access) but yes, a determined intruder can still get in completely undetected.

                  I’m going to have to ponder some more and get out there myself. Since my hunters have been busy out there, I haven’t ventured down and taken the chance I’d disturb their targets. But I might see how soon we can get out & scout out the area. I close on it, Monday. Since the bulk of that property is two very steep ridges and a creek-bottom field… the terrain has some natural “obstacles”. Including cliffs and boulders. Makes for a good funnel effect.

                  I’m going to have a lot of questions.

                • #92086

                    Excellent post. I need to re-read a few times. I wonder if in the real world; funneling the enemy works? IE give them one path which is narrow and well covered for them to take the easy path down. I would imagine an inexperienced enemy may fall for it. At least once.

                  • #92087
                    Joe (G.W.N.S.)

                      For low level threats, my plan is to replace some glass-windowed doors and maybe some unwelcoming thorny bushes around windows.

                      Good ideas, most can benefit from better doors and longer screws into the jams to secure it to house. There are a variety of methods.


                      Replacing interior doors with exterior doors.

                      …not necessarily all, but this can again layered defense and buy time.

                      You have two dogs (assuming newer adoption worked out) which provide early warning and at least visual deterance.

                      Depending on type already in place I would consider security window film on all ground floor/basement windows. Depending on age many basement windows have weak frames that need reinforcement.

                      I think about this topic a LOT, given it’s usually just me here.

                      I too am in this situation and rely on dogs, various sensors to include cameras w/audio, motion detectors, etc…

                      Consider too how some beneficial livestock can also react to predators (four and two legged) for additional redundancy.

                      We’ve discussed dogs in the past and I would start with one, but ultimately consider two for best results.

                      With property that size I would find a best map available, mark all trails/features, and divide it into zones with marked locations of appropriate sensors to alert to possible trespassers.

                      Various methods can be used to minimize wildlife detection, of course I enjoy identifying various game and it’s location. There is much “off the shelf” equipment that won’t break the bank available today.

                      Consider how various trees could be dropped to limit access. Surprising to some even Amazon has an extensive selection of Concertina and Razor Wire, check local first, but interesting.

                      Just some thoughts.

                      I wonder if in the real world; funneling the enemy works?

                      Fortunately not all threats will be experienced military! ;-)

                      Many factors involved, but yes it does work.

                    • #92088
                      D Close

                        Excellent article. The most valuable resource in this topic are trained shooters, working as a team. This should put to bed the notion of the porch-sniper-homesteader being in any way a viable option.
                        Max mentions the need to identify key terrain. Anyone who has taken the Force on Force class or similar, knows how this determines outcome to a large extent. If you’ve lost the high ground, you’ve in all likelihood lost the battle.
                        I liked the point about keeping obstacles under observation. That seems to be a manpower intensive exercise that most are not prepared for. My question is, how many? I realize without specifics this is impossible to answer, so I would post assumptions. A five acre lot, roughly square, with a secondary paved road on one side and a mix of fields and wooded on all others. Say one other side of the property allows approach by vehicle through a field while two other sides allow concealment. A single family house sits back from the road but well within small arms range. How many shooters, would be needed to secure such an area? Given: a threat of roving gangs and thieves, not military or rogue LE and a weapon threat of semi-auto rifles. What kind of watch/patrol schedule is desired? How big a QRF would be recommended? What would those patrols look like?
                        I got into a discussion with an acquaintance about a much bigger piece of property. My answer was ”a company.” This was rejected by this former Army infantry officer as too large and that our friend was better just keeping a low profile. With over 100 cattle I didn’t think this was possible. I can’t help thinking when control slips, numbers are going to count. Having the ability to scale up your numbers will be the determinant factor for survival, just as it has always been. He who gets there firstist with the mostist will win.

                      • #92089

                          Joe (G.W.N.S.) wrote:

                          Replacing interior doors with exterior doors.

                          …not necessarily all, but this can again layered defense and buy time.

                          You have two dogs (assuming newer adoption worked out) which provide early warning and at least visual deterance.

                          Yeah, hardening interior doors, at least our bedroom door, might be the first thing we do, my wife hates our interior doors. They are super thin hollow doors, unlike the vintage solid wood doors she’s used to. I’m pretty sure if someone tried to kick one of the doors down, their foot would just go straight through!

                          And yes, the second dog is working out. When we’re on walks, people unfamiliar with the breed generally cross the street. And they both are very vocal, especially the puppy, who barks at everything (including her own reflection).

                        • #92090

                            @D Close: yes this is a really good point. Got a platoon of minimum 24 plus head shed? Got a CUTT of 12 plus?

                            Ideally you want a rotation of elements on: Patrol, Quick Reaction Force, Guard, Rest. Numbers on each are what you have, and shoukd really be equal to the threat. Ideally minimum of 4 on each. You may have to can rest and make that during QRF, but that is not sustainable forever. How long are the rotations? 24 hours on each task? You can build rest into each of theae roles: you are for example not on patrol the whole time, as you vary patterns etc.

                            This is of course trained shooters only. You can utlize the less trained for sentry/watch roles. But of course we are talking infantry-style best practise here.

                            I am getting ready to write a follow up based on what most people actually have right now. The reality: a partially trained husband, untrained wife, dependent children. More to follow.

                          • #92091

                              Great article. On a larger scale, an example of the log/tree top abatis being employed was the Battle of Carillon(Ticonderoga) in 1758. The outnumbered French basically built a log defensive wall and placed the tree tops in front of the wall as an interlocking abatis. This slowed the British attack allowing the French to defeat a much larger British force. On a smaller scale tree tops overlapping on roads and other approaches would be cheap and easy to use. Thanks for the insight Max.

                            • #92092
                              Dark Knight

                                I have thought about this often. My property backs on to a somewhat busy 2 lane road (it leads to a development of McMansions). I plan to put a fence back there, with a removable section to be able to get the Jeep through. We are near a hill top, but line of site along the road is limited. there is only one road that actually leads to our neighborhood. Wife an I have discussed moving so we are in am less traveled area. For now I am considering purchase of a tree stand that I can put up to improve line of sight. I also plan to create other obstacles on the property. It is only a little over an acre.
                                I have not talked to others in the neighborhood, and the relationship with one of the closest house has become “tense.” Would like to move to a somewhat more isolated location, but still has to be close enough to DC for wife and I to commute. At least we are out of the hood in Arlington!
                                The next issue is to figure how to get home if something starts while I am stuck in DC!

                                Have a great weekend, y’all!

                              • #92093

                                  Great info. Looking forward to the follow up.

                                • #92094
                                  Joe (G.W.N.S.)

                                    How long are the rotations?

                                    That’s the part that makes this so manpower intensive.

                                    All of this just to keep safe and then you have to factor all of the basic housekeeping to live and support your life.

                                  • #92095

                                      For the moment, I think the surprise of meeting any kind of obstacle or armed resistance to intrusion would make it possible to get by with smaller numbers – but in the case of organized roving gangs, which one would be foolish not to expect as society and rule of law deteriorate further – then you need to have a network of people with whom you can expand those numbers quickly.

                                      While a property may not be able to support the actual numbers needed to properly defend against that kind of threat – that’s where local intel and mutual assistance agreements need to be worked out. I’m wanting to avoid the seige scenario for as long as practical. And I would expect it to be a given, that you’re going to be working with people who aren’t trained (or were trained poorly) and haven’t trained together. So the better you have understood the pluses/minuses of what you’re trying to defend and against what kind of threat… the better able you’ll able to communicate the tasks and divide up the areas of responsibility among trusted team leaders.

                                      I like the idea of having hard copy maps – both for planning meetings and smaller version for the “guest teams” you might only be able to train with, once a year. Clear mylar will let you mark positions/fortifcations and useful features – and where the pre-placed obstacles are – for your “friendlies”.

                                    • #148082
                                      Joe (G.W.N.S.)

                                        Giving current events this seems like a good time to revisit Max’s excellent Thread!

                                      • #148215

                                          Great discussion!

                                          CQB 04/19
                                          Heat 1 06/19
                                          Heat 2 08/19
                                          CLC 10/19

                                      Viewing 17 reply threads
                                      • You must be logged in to reply to this topic.