In brief
Most conversations about home security start with a single device – an alarm, cameras, sometimes the front door – and they end there. The house then gets one strong element and several weak ones beside it. In practice, home security is a handful of layers – the fence, the windows and doors, the door to the bedroom wing, the people who hold the keys – and each layer has one job: to buy time for the next. The decisions about those layers are made at different points of the build, from the site plan to the window order, and once the walls are plastered most of them cannot be undone. I write about what to require from each layer and when the time for it is. I do not design security systems and I do not assess risk profiles; what I do is make sure each of those decisions is taken in time, and that what ends up on site is what was asked for.
Why home security in layers
On a building site I keep the more expensive tools in a container closed with a padlock. Any padlock can be cut, and we all know it. The padlock is not there to stop anybody. It is there to make the cutting take longer than the drive of whoever gets the signal from the sensor inside. If there is no sensor, or nobody comes when it goes off, the padlock is just a padlock.
A house works the same way, only with more layers. No fence, window or door stops anybody who has enough time. Each of them delays. A sensor delays nothing; it raises the alarm. And the person who has to come needs time to get there. That is the whole arithmetic, roughly: the barriers have to hold somebody for longer than the road from the signal to the gate takes. If somebody gets over the fence unnoticed and the first sensor sits on a window, it goes off when that somebody is already standing at the house – and the whole walk across the plot, which could have been used, is gone. If, on the other hand, the barriers are good but the sensors only speak up in the bedroom, the time was there; nobody counted it.
Hence the layers. Each one assumes the previous one will be beaten, and that assumption is deliberate. The fence is meant to give a signal and a little time, the building envelope the next piece, the door to the bedroom wing another, and at the very end, if the risk profile calls for it, stands the safe room I have written about separately. From this follows a rule I repeat at every one of these layers: a sensor should speak up as early as possible, ideally before anybody touches the barrier – wherever that can be done without false alarms, and how hard that is outdoors is in the piece on the alarm. A sensor that goes off only after the glass is broken gives you information after the fact. Rather late.
The plot boundary – fence, gate, pedestrian gate
The subject starts at the fence, although most clients treat it as part of the garden. For me it does several things at once. It says where private ground begins. It forces anybody who wants in to pass through the gate or the pedestrian gate, that is, through the points you control, or to get over an obstacle, which takes time and can be seen. It carries the first detection and the lighting. And it delays. It will not stop anybody who has come with intent; there are no such fences, only ones that take longer.
At the site-plan stage I ask about four things. Whether you can see from the house who is standing at the gate before anybody opens it – from a window or from a screen. Whether the pedestrian gate is separate from the vehicle gate, so that a courier does not open the zone where the cars stand. Whether there is power and cable routing at the plot boundary, because without them detection on the fence stays in the estimate, and the gate has to be openable by hand when the power is out. And whether somebody has read the planting plan with an eye to what, in a few years, will screen the pedestrian gate and the camera; a hedge takes a long time to grow and nobody on the drawing sees it at its final size.
One thing I find myself discussing with clients more often than I expected. A high, solid wall gives privacy, and that privacy is real. Only a wall protects in both directions: whoever is already inside is screened just as well as you are. Behind a solid fence, detection on the grounds stops being an extra. (The neighbour who can see your gate is part of the system, though nobody asked him – and behind a wall he is gone.)
The decision on this layer is the earliest of all. Before the fence, the driveway and the paving close the ground, there have to be ducts for the cables to the pedestrian gate, the gate and the lights; with ordinary houses this is usually done alongside the foundations, and it is advice I give on every build. With a residence, add power and a route for detection along the boundary. The height and form of the fence are also governed by regulations and the local plan; the designer checks that before the drawing reaches me.
The building envelope – windows, doors, garage
The building envelope is the layer clients know most about, and the one where an expensive mistake is easiest to make. The mistake is buying a class and believing you have bought a layer.
Burglar-resistance classes describe who, and for how long, a barrier holds off under test: from somebody shouldering and kicking to somebody with power tools, with the time counted in laboratory minutes, not in the minutes of a real event. In Poland that language is the resistance classes for doors and windows under the EN 1627 standard, separate classes for glass and separate grades for alarm systems. It is a good language, because the designer, the manufacturer, the integrator and the insurer all speak it. Which class to require, I will not say. That follows from the risk profile, and a security consultant assesses it. What I will say is three things that get lost in that language most often.
First: the class applies to a complete, tested set. Leaf, frame, lock, hardware and glass are tested together and receive the class together. The glass has its own class under a separate standard, the hardware its own, but a window with glass “of a class” and hardware “of a class” does not thereby have a class as a window. The standard says so in plain terms: the choice of glazing and hardware alone does not determine the resistance of the product. If somebody shows you a glass certificate as a window certificate, they are showing you half a document.
Second: the test standards stop at the product. The class applies to a window or a door tested in a defined configuration; how the frame is anchored in the wall is something the standard does not cover. So the class arrives on site on a pallet, and whether it stays in the wall depends on the installation. Good installation will not make a class out of an ordinary window, but bad installation can take the class away from a good one. With an ordinary house the sentence “installation matters more than the product itself” is advice; with classed joinery it becomes a condition. At the joinery handover I therefore check not only that the leaf moves and the seals close, but that the frame sits the way the manufacturer described it, because that part of the class is on me. The factory finished its part on the pallet.
Third: a layer is defined by its weakest opening. Somebody who wants in through glass will not choose the front door in full view. They will choose a window at the side of the building, where nobody is looking. So the question “which class” comes second. The first is: are all the openings that can be reached at the same level – the ground-floor windows, the terrace doors, the fanlight above the front door, the garage door. A residence has many such openings and a lot of glass. A very strong front door next to an ordinary terrace window is one strong spot. It is not a layer.
Two details of this layer that clients usually do not know. A garage connected to the house is the easiest way in, and the door from the garage into the house is often an ordinary internal door. A burglar-resistant door in that spot is something I recommend for every house, not only a residence (it is also tighter than an ordinary internal door, so less of the garage smell gets into the house). And the roller shutters: the ones offers call “burglar-resistant” mostly have no tested class and are not a barrier. They keep out sun and wind. A product with a class exists; you have to ask for it separately. External venetian blinds are no obstacle to anybody. Add to that the opening sensors built into the joinery, which are ordered together with the windows; I wrote about them in the piece on the alarm system, so here I will only remind you that they are a line in the window quote.
When is this layer decided? Once, when the joinery is ordered. After that there is only replacement, and nobody plans replacing the windows of a finished house twice.
The bedroom door – the sleeping wing as a layer
The house has one more boundary, inside. The architect draws it for a different reason than I do: the day rooms, the guest rooms and the plant rooms on one side, the bedrooms on the other. The architect does it for quiet and privacy. For me that same boundary is the last barrier in front of people, and at night the only one that matters, because by then every other layer is behind you.
For that boundary to be a layer, it has to exist physically: one door that separates the whole bedroom wing from the rest of the house, can be locked from the day side, and opens from the inside with one movement, without searching for a key. Then what the alarm world calls night arming watches a real boundary: the system keeps an eye on the rest of the house while you sleep, and the boundary it keeps is something you can touch. Which class that door should be – again, a risk-profile decision. What matters is that there is somewhere to put it at all.
And that is a decision of the floor plan, the first sketches, before the structure is designed. A bedroom wing with a single entrance, no passage from the garage and no second door as a shortcut is something that no door can add to a finished house. If the risk analysis shows a need for a safe room, it stands inside this wing; I wrote about that in the piece on the panic room. What matters here is only that the safe room is the last layer, and the way to it leads through that door.
I would rather a family locked that door out of habit than out of fear. When the door is in the right place, that is what it looks like: it gets locked like the front door, without thinking.
Detection and response – the three pieces this one ties together
I write about the alarm, the cameras and the safe room separately; here it is only about where those three sit among the layers. Detection does not slow anybody down; that is the job of the layers described above. Detection raises the alarm, and it should do so before anybody touches a barrier. Response is people: the monitoring station, the patrol, the neighbour on the list, you – and the time it takes them to be at the gate is the one number all the layers have to be fitted to. How the layers of detection are arranged and why the house has to arm without somebody else’s server is in the piece on the alarm. Where the camera footage goes and why it should not leave the plot is in the piece on CCTV. Who really needs the last layer is in the piece on the safe room.
People and keys
In a residence the last layer is the people who hold keys, codes and permissions: the household, the staff, the service engineers, the gardener, the pool company, the guests. That list is long and changes from year to year. And it is the one layer you do not buy once. It has to be run.
The principle is simple: everybody gets as much access as their job needs, and not one key more. The pool technician does not need a key to the bedroom wing. The cleaner does not need the code that disarms the whole house. The installer of the home automation that runs the lights, the blinds and the gate does not need access to the alarm; I wrote about keeping those two systems apart in the piece on the alarm.
A mechanical key has one problem: whoever has it gets in, and usually no trace is left. Lose one key from the bunch that opens everything and you change the cylinders in the whole house. So the least I require from a mechanical key is that it cannot be copied at the first key-cutting counter: a protected profile, copies only with the card. And from electronic access control, three things. A permission has to be assigned to a named person. It has to be revocable without changing the lock. And it has to work without the manufacturer’s server, for the same reason I require that of the alarm.
Then two matters that only surface at handover. The administrator account of the system belongs to you from day one; the service code is not the owner’s code, and after the engineer leaves, nothing stays behind that you do not know about. And electronics must not lower the class of a door: a reader in a classed leaf is an intervention in a tested set, and you ask the door manufacturer about it before the installer picks up a drill.
The rest is procedure, and none of it is about distrusting anybody. Good staff prefer clear rules themselves. A register of who has what. Withdrawal of a permission on the same day somebody stops working for you. A list of “what stays behind” after every service visit. The house documentation in a counted number of hands. A family that knows what to do when the phone rings at night. And one thing no system will handle: the rhythm of a house that can be read from the street or from social media. That cannot be locked with a key.
Who writes the requirements, and who builds them
I am not a security consultant. I say so at the start because in this field the roles are easy to confuse: the alarm company will gladly answer the question about doors, and the door manufacturer the one about the alarm. The arrangement I work with looks like this.
The risk profile and the level of requirement for each layer are set by a security consultant: somebody other than the company selling the equipment, and somebody other than me. The architect turns those requirements into the plan: where the boundary of the bedroom wing runs, where the garage is, where the entrance is, how the fence relates to the house. The integrators for the alarm, the cameras and the access control receive the requirements in writing. The insurer reads the same classes and grades. The policy wording contains requirements for the security measures, and failing them can end in a refused or reduced payout, and that only after the loss. With ordinary houses I tell clients to choose the policy consciously, knowing its scope and exclusions. With a residence the insurer may well want to see the house and set conditions of its own, which is why that conversation happens before the design. Theft from the building site usually comes under the policy only once the house can be closed and somebody is watching it – the layers start working before you move in.
My job is simpler. I make sure each of those decisions is taken in time, and that what those people require can then be built. I tie together the trades that otherwise do not talk to each other (the window manufacturer does not know the integrator is waiting for his sensors, and the fencing crew does not know somebody had planned a cable there). And I hand over what was built against what was required: with the certificate for the set and the installation sheet in hand, because those are the documents the loss adjuster asks for after a claim.
When each decision is made
The easiest way to remember it is by the stages of the build, because that is the whole point of layers: each has its moment, and after it things get expensive or impossible.
Before the design: the risk profile and the requirements, with the consultant. At the concept and floor-plan stage: a bedroom wing with a single entrance, the position of the garage, a plant room with a door and a key, a safe room if there is to be one. At the site plan: the fence, the gate, the pedestrian gate, sightlines, planting, routes at the boundary.
At the structural design: everything that cannot be laid in reserve – reinforced partitions, if the profile calls for them. At the foundations and paving: ducts for the cables at the boundary. At the electrical first fix, before plastering: routes for the alarm, the cameras and the access control, power with backup. At the joinery order: the classes of the sets, the glass, the sensors in the windows and the installation description I will hold the crew to.
At fit-out: the door to the bedroom wing and the door from the garage into the house. Before handover: codes, accounts, the key register, the monitoring contract, the family’s procedures, the conversation with the insurer. After handover: running it, because this layer has no handover date.
Can all of this be added to a finished house? Part of it, yes: an alarm can be wireless, cameras can be run in trunking, locks can be replaced. The layout of the bedroom wing, the partitions in the structure and classed windows get added badly or not at all. That is why I bring this conversation up before the design, while everything is still on paper.
When layers are the wrong answer – and what I do not promise
When a simpler arrangement gives the same result. If the house stands where a neighbour can see your gate and the family hardly ever goes away, three layers of detection and a classed door to the bedroom wing may be an answer to a problem you do not have. I start by asking what we are defending against, and it happens that we end up with two layers instead of five.
When a layer gets in the way of living. A door that takes three movements to unlock stays open. A gate that takes too long to open stays open. A system that gets in the household’s way is switched off faster than anybody defeats it. Then it formally exists and really does not. The house under cameras is covered in the piece on CCTV; here I will only add that layers are designed so that the family does not fight them every day.
When security narrows to a single threat. More houses I know have been flooded by water than visited by anybody unwanted – at one of my clients a burst boiler flooded the house, and the policy turned out to be weak. Leak detection with a valve that shuts the water off by itself, smoke and carbon monoxide detectors, power that does not vanish with the storm – those are layers too, of a different category, with their own standards and their own logic. One rule joins both categories: what is closed to an intruder must be open for escape. An escape route cannot require a key from the inside. A safe room does not protect against fire – that is in the safe-room piece as well.
What I do not promise. That any layer will stop somebody who has come with intent and with time – none stops them; each only delays. That I will point you to a class or a grade, because that follows from a risk profile I do not assess. And that I will tell anybody, publicly or privately, what these layers look like at a specific client’s house.
What I ask before I say yes
- What exactly are we defending against, and who assessed it apart from the companies that want to sell something?
- Does the bedroom wing have a single entrance and a door that can be locked – and is that in the floor plan before the structure is designed?
- Are all the reachable openings at the same level – fanlights and the garage door included?
- Is the joinery class the class of a certified set – and do I have the manufacturer’s installation description to hold the crew to?
- Can you see from the house who is standing at the gate before somebody opens it – and is the pedestrian gate separate?
- Are there power and cable routes at the plot boundary before the fence and the paving close the ground?
- Who holds which keys and codes, how are they withdrawn, and can that be done without changing locks?
- Is the administrator account of every system yours – and what stays with the company that set it up?
- Has the insurer seen the requirements before they were fixed – and does it know the same things the designer does?
- Does the escape route open from the inside without a key, even when everything else is locked?
Frequently asked questions
How do I plan home security before the design exists?
From the risk profile and from the floor plan. Shopping comes last. First somebody who does this for a living answers what you are defending against; then the architect draws the bedroom wing, the garage and the entrance so that the layers have a place in the plan, and the site plan gets the fence, the gate and the routes at the boundary. The devices come last and are the easiest part. If the house already stands, you start from the same question, only part of the answer will be a compromise.
Which burglar-resistance class should I choose for doors and windows?
I do not settle that in a text. A class describes who, and for how long, a barrier is meant to hold off, so it follows from the risk profile, and a security consultant assesses that – neither the contractor nor the salesman. Without a profile I can say this much: the class has to be the class of a complete set, all the reachable openings have to be at the same level, and the installation has to follow the manufacturer’s description, because the standard stops at the product.
Does a high wall make a house safer?
It increases privacy and delays entry, but it also screens whoever is already inside. Behind a solid fence, detection on the grounds stops being an extra, and a view of the gate from the house becomes a requirement. The height and form of a fence are also governed by regulations and the local plan; the designer checks that.
Can security layers be added to a finished house?
Some, yes: an alarm, cameras, new locks, access control. The layout of the bedroom wing, reinforcement in the structure and classed joinery get added badly or not at all, because those are design decisions. In a finished house you therefore start with people and procedures – the layer that needs no chasing of walls, and is most often the weakest.
Answers to common questions about privacy and discretion are collected in the Questions section.
If you are thinking about a home where security is designed in from the start, that conversation belongs before the design exists. Let’s talk about your project.