Burglar-resistant door hardware starts with three things: an SKG*** cylinder with anti-snap protection, a security escutcheon that covers that cylinder so it protrudes no more than 3 mm, and multi-point locking on your back door and reachable windows. The goal is delay, not prevention. The Dutch police approval scheme Veilig Wonen sets three minutes of resistance as the standard, and that is exactly the threshold where most opportunist burglars give up. In the Netherlands, resistance class 2 to NEN 5096 is even a legal requirement for reachable facade elements in new-build homes. Source: Besluit bouwwerken leefomgeving, § 4.2.16
Hi there,
I am going to tell you something most security companies do not say out loud: you do not need a two-thousand-euro alarm system. For 300 to 800 euros of locks and hardware and one Saturday of work, you bring the burglary risk of an average house down a long way.
Because most burglaries are not film burglaries. It is someone walking past, seeing that it can be done, and wanting to be inside within two minutes. If it takes longer, he walks on to the next house. It really is that simple.
And here is the good news straight away: the number of recorded residential burglaries in the Netherlands has been falling for thirteen years in a row. In 2025 the police recorded roughly 21,600 residential burglaries, the lowest figure since digital recording began in 2012. Ten years ago it was around 71,000 a year. Better locks and hardware are a big part of the explanation.
But the risk has not gone away. And the chance of an offender being caught is small: that happens in just over four percent of cases. So you are mostly on your own front door.
In this article: how the certification schemes actually work, which break-in methods get used in practice and what stops them, how to measure your cylinder, and then step by step the fitting of cylinder, security escutcheon, door restrictor and window locks. Plus what it costs and in which order to start.
First, understand what burglary is really about
Delay, not prevention
There is no burglar-proof house. Anyone who really wants in, gets in. The whole system of certificates and standards revolves around one thing: time.
Resistance class 2 (the class required for Dutch new-build homes) means a facade element holds out for at least three minutes against a burglar with simple tools such as a large screwdriver and a wedge. Resistance class 3 means at least five minutes, and there the tester is also allowed a hammer, a crowbar and a drill.
Three minutes sounds short. But the average opportunist burglar stops after about three to five minutes, because the chance of being seen or heard gets too big. Those three minutes are not a random number.
Where do they get in?
The back of the house is by far the most used route. Which makes sense: less visibility from the street, a rear alley or a fence giving cover, and hardware that is often years older than at the front.
That is straight away the most important practical lesson of this whole article: most people invest in their front door and forget their back door, patio doors and kitchen window. If you only tackle one thing, tackle the back.
What counts as “reachable”?
The Dutch standard NEN 5087 determines which windows and doors count as reachable for a burglar, and therefore need securing. Roughly: any window or door whose bottom edge sits lower than about 5.5 metres above the adjoining ground is in principle reachable. Climbing options count too. An extension, a carport, a garage roof, a shed against the wall or a sturdy wheelie bin suddenly makes a first-floor window reachable.
So walk around your house with those eyes on. Can you climb onto a flat roof anywhere? Then the window above it is just as much a risk point as your back door. And so is that balcony window you never think about.
The certification schemes decoded
This is where most articles stay vague, and where you get lost in the shop. Let me be clear:
SKG stars: the quality of the product
SKG awards stars to individual products: locks, cylinders, escutcheons, window fasteners, hinges.
| Certificate | Means | Where to use |
|---|---|---|
| SKG★ | Basic security | Internal doors, low-risk storage rooms |
| SKG★★ | Increased security | The minimum for reachable doors and windows under the police approval scheme |
| SKG★★★ | Highest class, including protection against snapping, drilling, lock picking and bump keys | Front door, back door, patio doors |
The rule of thumb: SKG★★ is the minimum for reachable facade elements, SKG★★★ is what you buy for your cylinders. The price difference between a two-star and a three-star cylinder is usually 20 to 40 euros. Worth it, because the leading break-in method right now targets exactly the cylinder.
NEN 5096 and EN 1627: the performance of the whole element
Where SKG looks at individual products, NEN 5096 (Dutch) and EN 1627 (European) look at the complete facade element: frame, door, glass, hardware and fixings together.
- Resistance class 2 (also called WK2 or RC2): at least 3 minutes of resistance against simple tools. Required for reachable facade elements in Dutch new-build homes.
- Resistance class 3 (WK3 or RC3): at least 5 minutes, including against heavier tools.
Important to grasp: an SKG★★★ cylinder in a rotten frame is still worthless. The chain is as strong as its weakest link, and in many houses that is not the lock but the timber around it or the way the hinges are fixed.
The police approval scheme Veilig Wonen (PKVW)
The PKVW is not a product but a certificate for your home. An approved expert comes round, inspects the whole house and gives you a list of what needs doing. Once the work is done, a final inspection follows and you get the Secured Home certificate. A house completed more than two years ago falls under existing stock.
The PKVW looks wider than locks alone: also at lighting, visibility from the street, planting and fire safety.
Does it pay? Often it does. Many insurers give a discount on contents cover with a PKVW certificate. How much varies a lot per insurer, so ring your own insurer before you start and ask two things straight out: what is the discount with a PKVW certificate, and do you also accept individual measures without a certificate? Sometimes that second one is already enough for a lower premium.
Also check whether your council or housing association has a grant or scheme for security work to PKVW requirements. Several councils run them, but not all, so look on your own council’s website.
The break-in methods and what stops them
This is the part you need in order to understand what you are actually buying.
1. Cylinder snapping (the big one)
The burglar screws a large screw into the keyway of the cylinder and pulls the whole cylinder core out with a special tool. After that the lock is open in seconds. It is fast and it makes little noise, and that makes it the favourite method.
What stops it: two things together. An SKG★★★ cylinder has an internal snap line and a hardened element that resists core pulling. And a security escutcheon with anti-snap protection puts a hardened steel ring around the cylinder so there is nothing left to grab.
The detail where it goes wrong: your cylinder may protrude no more than 3 mm from the escutcheon. If it sticks out further, tools can be fitted onto it and the whole set-up does nothing. This is by far the most common mistake in DIY fitting.
2. Latch slipping (the card trick)
The burglar slides a thin plastic card or a strip of steel between door and frame and pushes the angled latch back. It only works if the door is not deadlocked, so relying on the deadbolt is the answer.
What stops it: always deadlock the door, even when you are only out for a moment. And an anti-jemmy strip over the door gap, which physically covers the opening.
3. Levering with a crowbar
The classic. The burglar puts a crowbar between door and frame and levers.
What stops it: multi-point locking (three to five locking points instead of one), hinge bolts on the hinge side, and an anti-jemmy strip that takes away the leverage gap.
4. Lifting the door off the hinge side
On outward-opening doors the hinges sit on the outside. Knock the pin out and the door comes off on that side.
What stops it: hinge bolts. These are steel pins that engage in the frame on the hinge side when the door is shut. They cost roughly 10 to 25 euros a set and are one of the cheapest measures there is. Many modern security hinges have them built in already.
5. Sneaking in through an open window
Not a break-in but a walk-in, and it happens more often than you think: a tilted window in summer, an open kitchen window while you are cooking at the far end of the garden.
What stops it: door and window restrictors, which let you set a window or door safely ajar without anyone being able to push it further open.
6. Breaking or cutting the glass
Less common than people think, because it makes noise. But on back elevations with plenty of cover it does happen.
What stops it: laminated security glass to EN 356, in class P4A or higher. That is several panes with PVB interlayers, so the glass holds together when it breaks. Save this for the genuine risk spots (reachable patio doors, a window behind a fence), because it is not cheap and it is a job for a glazier.
Working out your cylinder size (do this first)
Before you order anything: measure your cylinder. Almost all DIY fitting problems come from the wrong size.
Step 1. Undo the retaining screw in the faceplate of the lock (the narrow strip in the edge of your door). It is usually a long M5 screw, roughly level with the cylinder.
Step 2. Put your key in and turn it a small way (about a quarter turn) so the cam turns with it. Now pull the cylinder out. If it will not come, wiggle it gently while turning the key slightly back and forth.
Step 3. Put the cylinder on the table. Measure from the centre of the cam (the black turning plate) to the left, and from the centre to the right. Those are your two sizes, for example 30/40.
Step 4. Note down which size is the outside. That is always the first number when ordering. A 30/40 and a 40/30 are two different cylinders.
Cylinder sizes go in 5 mm steps: 30, 35, 40, 45, 50 and so on.
The rule to remember: on the outside, the cylinder including the escutcheon may protrude a maximum of 3 mm. If your current cylinder sticks out further, order a shorter size for the outside. If it sticks out too little, you cannot get the key in properly, so take 5 mm longer.
Extra tip: measure the thickness of your new security escutcheon as well. Escutcheons with anti-snap protection are often thicker than your old ones. Pick your new cylinder size for the new situation, not the old one.
What you need
Tools
– Cordless screwdriver with bits (PZ2 and PZ3, and torx)
– Set of hand screwdrivers
– Tape measure and pencil
– Drill with wood bits 2, 3 and 10 mm
– 18 mm chisel and wooden mallet
– Spirit level (30 cm)
– Possibly a router or a sharp bevel chisel for letting in keeps
Materials per door (indicative)
– SKG★★★ cylinder in the right size
– SKG★★★ security escutcheon with anti-snap protection
– Anti-jemmy strip (2 metres, in the colour of your frame)
– Hinge bolts or security hinges
– Stainless steel screws of at least 40 mm (the supplied screws are often too short)
– Possibly a multi-point lock or a surface-mounted lock
Step-by-step 1: fitting the SKG cylinder and security escutcheon
Allow 30 to 60 minutes per door. This is the single most important thing you can do.
Step 1: take the old escutcheon off
Unscrew the handle or knob and the roses or backplate. On cheap hardware the fixings often sit on the outside, which is a weakness in itself.
Once the lock is exposed, take a moment to look at its condition. Is the lock case itself still sound? Does the deadbolt turn smoothly? Is there play in it? Replacing a worn lock case costs 40 to 100 euros, and right now is the easiest moment to do it.
Step 2: take the old cylinder out
Retaining screw out of the faceplate, key a quarter turn, pull the cylinder out. See the section above.
Step 3: fit the outer plate first
A security escutcheon with anti-snap protection consists of an outer plate (with the hardened ring around the cylinder) and an inner plate. They are screwed to each other through the door, with the screw heads on the inside. That is essential: nothing may be unscrewable from the outside.
If the outer plate sits crooked, the cylinder will not pass through. Keep it loose until the cylinder is in.
Step 4: slide the new cylinder in
Key in, quarter turn so the cam lines up with the cylinder body, then push it through.
Now do the retaining screw in the faceplate up finger tight only, and check:
- Does the cylinder protrude a maximum of 3 mm from the escutcheon on the outside? Measure it, do not guess.
- Does the key turn smoothly, from both sides?
- Can you open and close the door without anything binding?
If the protrusion is wrong, stop and order the right size. A cylinder sticking out 8 mm with an expensive anti-snap escutcheon around it is less safe than a cheap cylinder sitting neatly flush.
Step 5: tighten everything up for good
Retaining screw done up (do not overtighten, it is soft steel), escutcheon screwed home, handle or knob on.
Choose a fixed knob on the outside, not a lever handle. With a lever handle outside, a burglar can use it as a lever.
Step 6: test with the door both open and shut
Close the door and lock it. Check that the deadbolt goes fully into the keep. On a door that has dropped or swollen it will bind, and then people stop deadlocking it. And that is exactly the situation in which the card trick works.
If it binds: adjust the keep by filing the holes out a little, or move it a few millimetres.
Step-by-step 2: anti-jemmy strip and hinge bolts
Fitting an anti-jemmy strip
An anti-jemmy strip is a steel or aluminium angle profile that you screw over the gap between door and frame. It takes away the leverage gap and protects the point where the bolt enters the keep.
- Measure the height of your door and cut the strip to length, or buy it in the right length.
- Work out which strip you need: on an inward-opening door you fit it to the frame, on an outward-opening door to the door itself.
- Hold the strip in place, mark the holes, pilot drill at 3 mm.
- Screw it home with stainless steel screws of at least 40 mm, so they bite into the solid part of the frame. A screw every 25 to 30 cm.
- Check that the door still closes freely.
Most important point: the supplied screws are often 25 or 30 mm. That is too short. A strip held by little short screws pulls out with the first crowbar movement and has then only cost you money.
Fitting hinge bolts
You only need hinge bolts on outward-opening doors and windows, where the hinges sit on the outside.
- Fit the pin to the door, on the hinge side, at roughly one third and two thirds of the height.
- Close the door and mark where the pin touches the frame.
- Drill a 10 to 12 mm hole there, or fit the supplied plate.
- Check that the door still closes smoothly and the pin drops neatly into the hole.
Allow 15 minutes per door and 10 to 25 euros per set. Ratio of effort to result: excellent.
Step-by-step 3: door and window restrictors
A restrictor holds a window or door open at a fixed gap. You can ventilate or take something in at the door without anyone being able to push it further open. For families with small children it doubles as a fall guard.
Which one do you pick?
| Type | For what | Watch out for |
|---|---|---|
| Door restrictor | Front door, back door | Choose a version with SKG certification if it also has to do a security job |
| Window stay with locking catch | Outward-opening windows | Usually the simplest and the most widely used |
| Restrictor for tilt-and-turn windows | Tilt-and-turn windows | Trickier, because the window has to move in two directions. Check carefully that the type suits your hardware |
| Surface-mounted lock | Inward and outward-opening windows | Two parts, simple to fit, widely usable |
Tilt-and-turn windows are the hardest category here. The hardware has to move in two directions, and many universal restrictors block that. In practice, people with tilt-and-turn windows more often go for a window stay or a storm catch as an addition to the existing mechanism, rather than a classic restrictor.
Fitting
- Decide the gap you want. For ventilation, 5 to 10 cm is usually enough, and that is narrow enough that nobody gets through.
- Hold both parts in place in the closed position and mark with a pencil. Use a spirit level: if it sits crooked, it will bind.
- Pilot drill at 2 or 3 mm. In timber always pilot drill, otherwise it splits.
- Screw the part on the opening sash home first, then the part on the frame.
- Test in every position: shut, ajar, fully open.
Choose stainless steel outdoors. Zinc-plated steel seizes up with rust within a couple of years, and then you have a restrictor that no longer moves.
Step-by-step 4: window security
Windows are the part that gets forgotten most often, while in reachable positions they matter just as much as the doors.
Locking window handles
The simplest upgrade: replace your ordinary window handle or espagnolette with a version that has a cylinder lock and SKG certification. Cost: roughly 20 to 50 euros per window.
Fitting is usually one to one on the existing holes, but measure the spindle centres and the spindle length beforehand. Take a photo of your current fastener and bring it to the shop.
Important for escape routes: do not lock a bedroom window and do not store the key in the loft. In a fire you have to be able to get out. Hang keys within reach but out of sight and out of arm’s reach of a broken pane.
Surface-mounted locks
A surface-mounted lock is two parts that you screw onto the window and the frame. They suit both inward and outward-opening windows and are popular because fitting is easy: hold in place, mark, pilot drill, screw home.
For reachable windows you rarely open (a toilet window, a ground-floor bathroom window) this is the fastest win available.
Multi-point locking on windows
On larger windows one locking point is not enough: the window can then be levered at the top and bottom. An espagnolette with several locking points solves that, but it is generally work where you have to rout into the opening sash. If you cannot do that, this is the part where you ring a joiner.
Sliding and patio doors
This is the weak spot in a lot of houses. A sliding door can often be lifted out of its track.
- Fit anti-lift blocks in the top track so the door cannot rise
- Put a bar or a dedicated sliding door lock in the track
- On patio doors, consider multi-point locking and laminated glass
Cellar and garage windows
Do not forget them. A 40×30 cm cellar window looks too small, but it gives access to spaces where someone can work on the internal door in peace. A steel grille or bars are often more effective here than a lock.
In which order do you tackle it?
If your budget is limited, do this, in this order:
1. Back door and patio doors (100 to 250 euros). Most burglars come in here. SKG★★★ cylinder, anti-snap escutcheon, anti-jemmy strip.
2. Front door (100 to 250 euros). Same package. Plus a door restrictor if you are often home alone.
3. Reachable ground-floor windows (20 to 50 euros per window). Locking window handle or a surface-mounted lock.
4. Remove the climbing routes (0 to 100 euros). Wheelie bin away from the wall, ladder locked in the shed, no sturdy climbing tree right next to a window, and the extension you can climb onto gets secured windows above it.
5. Visibility and lighting (30 to 150 euros). Outside lighting with a motion sensor at the back. A high fence or dense planting gives the burglar cover, so cut back the sightlines from the street.
6. First-floor windows above reachable roofs (20 to 50 euros per window).
7. Laminated security glass (from around 150 euros per m²). Only on the genuine risk spots. This is the most expensive step and the last one.
What does it cost?
| Item | Range | DIY? |
|---|---|---|
| SKG★★★ cylinder | 40 to 120 euros each | Yes, 15 minutes |
| SKG★★★ security escutcheon with anti-snap protection | 50 to 150 euros per door | Yes, 30 minutes |
| Anti-jemmy strip (per door) | 25 to 70 euros | Yes, 30 minutes |
| Hinge bolts (set) | 10 to 25 euros | Yes, 15 minutes |
| Door restrictor | 20 to 60 euros | Yes, 20 minutes |
| Locking window handle | 20 to 50 euros per window | Yes, 20 minutes |
| Surface-mounted window lock | 15 to 40 euros each | Yes, 15 minutes |
| Multi-point door lock (materials) | 150 to 400 euros | Only with routing experience |
| Laminated security glass P4A | From roughly 150 euros per m², fitted | No |
| PKVW inspection and certificate | Ask about the cost up front, it varies by company and region | No |
Doing an average terraced house entirely yourself (front door, back door, patio doors, four reachable windows) comes to roughly 350 to 800 euros in materials. Have it all done for you and reckon on roughly 1,200 to 2,500 euros including labour.
Set against that: the average loss from a residential burglary (belongings plus damage to door and frame) easily runs into thousands of euros, and the hassle around it does not get counted in euros at all.
The 8 mistakes that make your security worthless
1. The cylinder protrudes more than 3 mm. Then snapping is simply back on the table, even with three-star hardware. Measure it after fitting.
2. Hardware that can be taken off from outside. The screw heads belong on the inside. If there is a screw in the escutcheon from outside, something is wrong.
3. Screws that are too short. Supplied screws are often 25 to 30 mm. On keeps, anti-jemmy strips and hinges you use at least 40 mm, so they bite into the solid timber or the metal of the frame and not just the facing layer.
4. A strong lock in a weak frame. Rotten timber, a thin uPVC frame with no steel reinforcement, or a 30 mm hardboard door: no cylinder helps there. Sort out the frame first.
5. Only tackling the front door. The back is the most used route. Start there.
6. Not deadlocking the door. A lock that does not get used is not a lock. Always throw the deadbolt, even when you are just next door at the neighbours’. Without the deadbolt, the card trick is all it takes.
7. Leaving the key in on the inside. On a door with glass or a letterbox, a key on the inside can be turned with a tool. Take it out and put it in a fixed place out of sight.
8. Spare key under the mat, in the plant pot or in the key safe by the door. Those are the first three places anyone looks. Give a spare key to a neighbour.
Extra: the measures that cost nothing
Locks and hardware are the foundation, but these things genuinely help too, and they cost you nothing:
- Make your house look lived in. Timer lights inside, no overflowing letterbox, curtains not closed for days on end.
- Put your tools away. A ladder, a wheelbarrow or a spade in the garden is equipment you are lending the burglar. Lock the shed.
- Clear the climbing routes. Bins, garden chairs and crates away from the wall.
- Do not share your holiday live on social media. Post afterwards.
- Clear the sightlines to your back door from places where neighbours or passers-by can see, and do plant things that make climbing awkward (thorny shrubs under reachable windows).
- Leave a light on at the back, or put a motion sensor there.
- Report anything suspicious. Neighbourhood apps work, but only if things actually get reported.
Frequently asked questions
What is the difference between SKG★★ and SKG★★★?
SKG★★ stands for increased security and is the minimum for reachable doors and windows under the police approval scheme Veilig Wonen. SKG★★★ is the highest class and adds protection against snapping, drilling, lock picking and bump keys. For cylinders I always advise SKG★★★, because snapping is the most used method and the price difference is usually only 20 to 40 euros.
How do I know which cylinder size I need?
Undo the retaining screw in the faceplate in the edge of your door, put the key in the cylinder, turn it a quarter turn and pull the cylinder out. Then measure from the centre of the cam to the left and to the right. Those are your two sizes, with the outside being the first number. Sizes go in 5 mm steps. Bear in mind that your new security escutcheon can be thicker than your old hardware, and that the cylinder may protrude no more than 3 mm on the outside.
Is burglar-resistant door hardware compulsory?
For new-build homes in the Netherlands, yes: reachable doors, windows and frames must meet resistance class 2 to NEN 5096, which comes down to at least three minutes of burglary resistance. For existing homes there is no legal requirement. Your insurer can, however, set security conditions in the policy, so read your policy terms.
Do I get a discount on my insurance with the police approval scheme?
Often yes, but how much varies a lot per insurer. Ring your own insurer before you start and ask two things: what discount applies with a PKVW certificate, and do you also accept individual measures without a certificate? Also ask your council or housing association whether a grant scheme for security work exists.
Can I do all this myself, or do I need a locksmith?
Cylinders, security escutcheons, anti-jemmy strips, hinge bolts, restrictors, window handles and surface-mounted locks are all perfectly doable yourself with basic tools. What you hand over: fitting a multi-point lock (routing work in the opening sash), replacing glass, and repairing rotten or dropped frames. If you want a PKVW certificate, an approved company has to carry out the inspection.
My door is uPVC or aluminium. Does this still work?
Yes, but watch the fixings. In uPVC frames the screws have to bite into the steel core reinforcement, not just the plastic. If that reinforcement is not there (it happens with cheap profiles), the hardware pulls out under load. In aluminium you drill and tap into the profile. If you are unsure, check with a magnet whether there is steel in the profile.
Does an alarm system help more than good locks and hardware?
For most homes, good locks and hardware are the first and best investment, because they physically stop the burglar instead of only reporting that he is inside. An alarm is a useful addition, not a replacement. Start with the mechanical security and only then look at electronics.
What do I do about a tilted window in summer?
A tilted window on the ground floor or above a reachable roof is a walk-in route: the hardware can often be operated from outside through the gap with a bit of tooling. Do not leave windows on the tilt when you are out or asleep on another floor. If you do want to ventilate, use a restrictor or a window stay with a locking catch, or ventilate through a window in a position that is not reachable.
Get to work
The core of it in eight rules:
- Start at the back, not at the front door.
- SKG★★★ cylinder with anti-snap protection, always.
- A security escutcheon around it, with the screws on the inside.
- Maximum 3 mm protrusion. Measure it afterwards.
- Anti-jemmy strips and hinge bolts are cheap and effective.
- Reachable windows get a locking fastener.
- Clear away the climbing routes and the tools.
- Always throw the deadbolt on your door.
Do point 4 properly. I have seen it too often: someone buys the best hardware for 200 euros and then fits a cylinder that sticks out a centimetre. Then you have an expensive knob on an open door.
Want to learn to tackle your whole house the way a tradesman does, from doors and frames to walls, floors and finishing? Then have a look at Koning van Je Woning. Explained step by step, without guesswork and without an expensive tradesman.
Regards from Fred Schouten, DIYer through and through
PS: those screws that come with your anti-jemmy strip. Throw them away and buy 40 mm stainless steel screws. A strip hanging on 25 mm screws in the facing layer comes off with one movement of a crowbar. Small tip. Big difference.