Home Security Hardware Guide

Securing your home starts with the doors and windows. In the UK, most burglaries involve forced entry through a vulnerable door or an easily opened window. The right hardware – cylinders, locks, chains, bolts and window security devices – makes a significant difference to how easy or difficult it is to break in.

This guide is written for both trade professionals and DIY customers and is based on commonly used UK standards, building regulations and good practice. It covers how to choose, measure and fit security hardware, with practical advice for timber, PVCu, aluminium and composite doors and windows.

If you need to browse suitable products while reading, take a look at our dedicated home security section, where you’ll find anti-snap cylinders, door chains, window locks and accessories from leading brands such as Yale, ERA, Mila, Avocet, Maco and more.

Cylinder security ratings

The cylinder (often called a euro cylinder) is usually the most vulnerable part of a modern multipoint locking door. Criminals know this and target poor-quality cylinders using snapping, drilling and picking techniques. Understanding cylinder security ratings is essential if you want effective door security.

Understanding cylinder types

In UK domestic properties you’ll typically see:

Euro profile cylinders – the most common on PVCu, composite and many timber multipoint locking doors

Oval cylinders – less common, often on older aluminium or commercial doors

Rim cylinders – used with rim nightlatches (e.g. Yale-type locks) on timber doors

Key/key cylinders – key-operated from both sides

Thumbturn cylinders – key outside, thumbturn inside for keyless exit

When people talk about “anti-snap cylinders”, they almost always mean security-rated euro profile cylinders used with multipoint locks. If your front or back door has lift-lever or key-operated multipoint locking, the euro cylinder is what you’re upgrading.

Common attack methods on cylinders

Burglars target weak cylinders in several ways:

Cylinder snapping – gripping and breaking the cylinder at the fixing point to access the cam and operate the lock

Drilling – drilling out the pins or shear line so the plug can rotate

Lock bumping – using a specially cut bump key to shock the pins into alignment

Picking – manipulating the pins individually to unlock

Cylinder snapping is particularly common on basic euro cylinders that protrude beyond the handle or escutcheon. A good anti-snap cylinder and high-security handle set can dramatically reduce this risk.

UK cylinder security standards

In the UK, several standards and schemes apply to cylinder security. The main ones are:

TS 007:2014+A2:2018 – a BSI technical specification for enhanced security cylinders and security door furniture. Products are rated in stars:

1-star cylinder – resistant to drilling, picking and bumping, but needs additional protection from 2-star door furniture

3-star cylinder – offers enhanced protection, including anti-snap features, and does not require additional security furniture

Sold Secure SS312 Diamond – a high level of independent testing carried out by Sold Secure (part of the Master Locksmiths Association). Diamond-rated cylinders are considered among the most secure and typically offer advanced anti-snap and anti-drill features.

BS EN 1303 – a European standard covering durability and basic security for cylinders. It sets minimum requirements but is not as focused on anti-snap as TS 007 and Sold Secure.

For domestic external doors, security-conscious homeowners, insurers and many police crime prevention officers will recommend:

TS 007 3-star cylinders; or

TS 007 1-star cylinders used with TS 007 2-star security handles; or

Sold Secure SS312 Diamond-rated cylinders

Common UK brands offering high-security anti-snap cylinders include Avocet ABS, Yale Platinum 3 Star, ERA Fortress, Mila ProSecure and others. You’ll find a range of these in our euro cylinders category, clearly labelled with their star or Sold Secure rating.

How to choose the right cylinder rating

When upgrading, consider the following:

Risk level – street-front doors, doors in secluded alleys and doors not overlooked by neighbours benefit most from 3-star or Sold Secure Diamond cylinders.

Insurance requirements – some insurers specify a standard (e.g. TS 007 3-star). Check your policy wording.

Door type – PVCu and composite multipoint doors are frequent targets for snapping; timber doors with mortice locks are less vulnerable, but cylinders on rim locks or cylinder-operated deadlocks still benefit from upgrades.

Convenience – consider key-alike options (one key for multiple doors) and whether you want thumbturns for internal escape without a key.

For most modern UK homes, a TS 007 3-star or SS312 Diamond-rated anti-snap cylinder is the recommended baseline for front and back doors.

Measuring a euro cylinder

Accurate measuring is essential. A badly sized cylinder not only looks untidy but can also be a security risk if it protrudes too far.

You measure a euro cylinder from the centre of the fixing screw hole:

Open the door

Locate the cylinder retaining screw on the edge of the door (usually at handle level)

Measure from the centre of that screw hole to the end of the cylinder on the inside (this is the internal length)

Then measure from the centre of the screw hole to the end of the cylinder on the outside (this is the external length)

Cylinders are described as external length/internal length (or sometimes the reverse), in millimetres. Common sizes include:

35/35 (70mm overall)

40/40 (80mm overall)

40/45 (85mm overall)

45/45 (90mm overall)

Trade tip: When upgrading, always treat the outside as the more critical side. Aim for the cylinder to be:

Flush with, or

No more than 2–3mm proud of, the handle backplate or escutcheon

A cylinder sticking out further is easier to grip and snap. If you’re between two sizes, most professionals will err on the side of slightly shorter for better security, as long as the key can still be fully inserted and turned.

For thumbturn cylinders, measure in exactly the same way. The thumbturn side is normally installed on the inside for easy exit in an emergency.

Replacing a euro cylinder – DIY guidance

For most PVCu and composite doors, changing the cylinder is straightforward:

Open the door and support it properly

Remove both handles if necessary (usually two screws through the backplate)

Locate and remove the central cylinder retaining screw from the door edge

Insert the key in the cylinder, gently turn it about 10–20 degrees to line up the cam

Slide the cylinder out of the door – you may need to wiggle slightly as you turn the key

Insert the new cylinder, again turning the key slightly so the cam passes through the lock case

Refit the retaining screw and handles, checking that the operation is smooth

If the key feels tight or the handles do not operate easily after refitting, do not force them. Check for misalignment, overtightened handle screws or incorrect cylinder sizing. For more complex issues, such as worn multipoint lock gearboxes, browse our multipoint locks or consult a locksmith.

Door chain and bolts

Door chains, limiters and bolts provide an extra layer of security on top of your primary lock. They help you control how far a door can be opened and offer additional resistance in the event of a forced entry attempt.

When and why to use door chains

Door chains and limiters are particularly useful for:

Flats and maisonettes where the front door opens directly onto a communal hallway

Vulnerable residents who want to verify callers without fully opening the door

Properties with solid timber doors where retrofitting chains and bolts is simple and effective

While a door chain is not a substitute for a secure lock, it can:

Allow you to check ID or talk to callers with the door partially restrained

Provide an extra point of resistance if someone tries to push past when the door is initially opened

Act as a visual deterrent, signalling that the property is security-conscious

Many UK insurers and police guidance notes refer to “door chains or limiters” as part of a layered security approach, especially on the main entrance of flats.

Types of door chains and limiters

The main types you’ll see in our home security and door accessories ranges are:

Traditional door chains – a chain runs between a plate on the door and a receiver on the frame. Commonly available from brands like Yale and ERA in brass, chrome and other finishes.

Door restrictor/swing bar limiters – a hinged arm mechanism that swings across to hold the door partially open. Often considered stronger and less prone to tangling than a chain.

Security door viewers – while not a chain or bolt, a wide-angle viewer (spyhole) is often fitted alongside a chain to allow visual checking before opening.

Look for robust construction, good quality fixings and, where possible, through-fixings into solid timber rather than just relying on short screws.

Positioning and fitting a door chain – practical tips

On a typical timber front door:

Fit the chain or limiter at a convenient height – often around 1,400–1,600mm from the floor so it is easily reachable but high enough to resist force

Ensure the chain anchor on the frame fixes into solid timber, not just into a thin architrave

Use the longest screws that will fully seat without piercing through the opposite side of the frame

Mark the position carefully with the door closed, so that the door opens enough to converse and pass small items, but not enough for someone to squeeze through

Trade advice: Where the frame is weak or the wall construction is poor, a chain alone may not offer much protection. Consider combining a chain with:

A BS 3621 mortice deadlock or a PAS 24-rated multipoint lock

Hinge bolts (particularly on outward opening doors)

A door viewer to avoid opening at all until you know who is outside

Door bolts and additional locking

Bolts provide extra locking points, particularly useful on timber doors, French doors and some older aluminium doors. Common types include:

Surface-mounted barrel bolts – simple slide bolts fitted on the inside. Ideal for back doors and secondary entrances, but not usually insurance-rated as the main lock.

Rack bolts – morticed into the door edge and operated by a removable key from one or both sides. Often fitted at the top and bottom of timber doors and French doors for extra security.

Sash jammers – surface-mounted devices used on uPVC doors and windows to prevent levering even if the main lock is compromised.

When fitting bolts on timber doors, aim to install them at approximately 150–300mm from the top and bottom edges to maximise resistance to levering. Use a sharp chisel and accurate marking for morticed rack bolts to ensure smooth operation.

Fitting chains and bolts to PVCu and composite doors

PVCu and composite doors often have reinforced frames and skins that are not as simple to screw into as solid timber. To avoid damage:

Use products specifically designed for PVCu/composite where available – some chains have fixing kits that engage the steel reinforcement inside the frame

Pre-drill pilot holes carefully and avoid overtightening screws, which can strip the plastic

Check for glazing, reinforcement and internal steel before drilling – use shorter screws where necessary but ensure they bite into something solid

Consider security door restrictors that fit to the internal face of the door and frame without compromising the weather seal

If in doubt, consult the door manufacturer’s guidance; many composite door suppliers specify where fixings can and cannot be added without affecting the door’s structural performance or warranty.

Window locks

Windows are a common entry point for burglars, especially when left on the latch or when the locks are missing or broken. Good window security doesn’t have to be complicated, but it does need to be appropriate for the window type and in line with insurance expectations.

Why window security matters

Insurers typically expect all accessible windows (usually defined as those on the ground floor or reachable from flat roofs, balconies or drainpipes) to be fitted with key-operated locks or built-in multi-point locking systems.

From a security standpoint, poorly secured windows can be:

Levered open if only held by a simple latch

Forced by attacking weak keepings or worn hinges

Lifted out of the track on some older sliding designs

Modern PVCu and aluminium windows usually incorporate multi-point locking with espagnolette or shootbolt mechanisms, but the handles and keeps can still wear or fail over time, reducing their effectiveness.

Types of window locks and hardware

Different window styles use different hardware. Common UK types include:

Espag (espagnolette) handles and locks – used on most modern PVCu and aluminium casement windows. A square spindle (normally 7mm) from the handle operates a gearbox linked to locking cams or shootbolts around the sash.

Cockspur handles – found on many older PVCu and aluminium windows. A hooked nose (spur) pulls the sash tight against a wedge or plate on the frame. These often use a simple keyed mechanism for security.

Sash window locks – for vertical sliding sash windows (timber or PVCu). These include fasteners that draw the sashes together and additional key-operated bolts that secure the sashes to each other or to the frame.

Window restrictors – devices that limit the opening distance (often for child safety) while still allowing ventilation. Some are releasable for cleaning or escape in an emergency.

Fanlight catches and locks – simple locking catches for small top-hung windows, often key-operated to meet insurance requirements.

Our window locks and window handles ranges cover most common systems used in UK homes, from widely used brands such as Mila, Maco, ERA and Yale.

Window security standards and regulations

While there isn’t a single “window lock standard” equivalent to TS 007 for cylinders, several standards and schemes are relevant:

PAS 24 – “Enhanced security performance requirements for doorsets and windows.” Modern windows tested to PAS 24 offer resistance to common attack methods as part of a complete unit.

Secured by Design (SBD) – the official police security initiative. Windows that are “Police Preferred Specification” are usually PAS 24-compliant and incorporate tested security hardware.

Approved Document Q (ADQ) of the Building Regulations – applicable to new-builds and certain change-of-use properties in England. It requires doors and windows in new dwellings to meet specific security performance, typically via PAS 24 or equivalent.

For existing properties, insurers usually focus less on formal standards and more on whether:

Accessible windows are fitted with key-operated locks

The locks are actually used and the keys removed

The windows are sound, correctly aligned and not obviously weakened

Measuring and selecting replacement window hardware

Getting the measurements right is key to a straightforward replacement job. Here are some of the most important dimensions to know.

Measuring espag window handles

For espag handles (PVCu/ aluminium casements):

Screw centres – measure the distance between the centres of the two fixing screws (commonly 43mm on most modern UK windows).

Spindle length – the 7mm square spindle length from the base of the handle to the tip. Common lengths are 10mm, 15mm, 20mm, 30mm and 40mm. Remove the old handle and measure the spindle that protrudes.

Handing – some espag handles are inline (non-handed) and can be used left or right. Others are handed; check whether your existing handle points left or right when closed.

Measure carefully in millimetres and choose a handle that matches screw centres and has a spindle length equal to or slightly longer than the existing one (you can cut down longer spindles if necessary).

Measuring cockspur window handles

Cockspur handles rely on “step height”:

Step height – the distance from the underside of the handle base to the underside of the spur (the part that hooks over the frame wedge). Common step heights are 9mm, 13mm, 17mm and 21mm.

To measure:

Remove the existing handle

Measure from the flat underside of the base to the underside of the spur that latches over the frame

Also note:

Screw positions – count how many screws are used (usually 3 or 4) and measure the centres if possible. Many replacement handles come with adjustable wedges to suit different frames.

Sash window locks – basic measurements

For timber sash windows:

Check the stile width to ensure the lock body will fit comfortably without weakening the timber

For stop bolts or sash locks fitted through the meeting rails, measure the timber thickness and choose bolts long enough to engage solidly without protruding

Many sash security kits are adjustable and include packers or sleeves for different window thicknesses.

Common window security problems and solutions

Problem: Window handle turns but doesn’t lock securely

The espag gearbox or shootbolt mechanism may be worn or broken. Replacing the handle alone will not solve it if the internal mechanism has failed. Identify the lock brand (often stamped on the metal strip – e.g. Maco, Roto, Mila) and backset, then source a compatible replacement gearbox or full mechanism.

Problem: Window is draughty or difficult to close

Adjust the cams or mushrooms on the espag strip; many are eccentric and can be rotated to increase or decrease compression against the keeps.

Check that keeps are firmly fixed and in line; loose or misaligned keeps reduce both security and weather sealing.

Problem: Keys for window locks have been lost

For cockspur and espag handles, replacement handles with new keys are often the simplest solution.

For older surface-mounted window locks, you may be able to source new keys from the brand and key number, but replacing the lock is often more economical.

Upgrading to locking handles and well-adjusted multi-point mechanisms will significantly improve both security and usability. Our window security section includes restrictors, sash locks and secondary security devices tailored to common UK window types.

Insurance requirements

Understanding what your insurer expects can save you trouble if you ever need to make a claim. Most UK home insurance policies specify minimum door and window security standards, especially for theft cover.

Typical UK insurer expectations

While wording varies, many insurers require the following as a minimum:

External doors (timber) – a 5-lever mortice deadlock or sashlock conforming to BS 3621 (or BS 8621/BS 10621 for variants), or a multi-point locking system with at least three locking points.

External doors (PVCu/composite) – a multi-point locking system with top and bottom hooks/bolts and a central deadbolt, operated by a key, often with a euro cylinder.

Patio/sliding doors – key-operated multi-point locking or top and bottom key-operated bolts, plus anti-lift devices where applicable.

Accessible windows – key-operated locks on all ground floor windows and on any upper floor windows that are reachable (e.g. from a flat roof or balcony).

Many insurers also require that:

All locks are put into full operation when the property is unattended

Keys are removed from locks and placed out of sight but accessible in an emergency

Any alarm system specified in the policy is set when the property is empty

Reading your policy wording

Look for a section titled “Minimum Security Requirements” or similar. Common phrases include:

“5 lever mortice deadlock conforming to BS 3621 or equivalent”

“Multi-point locking system with key-operated cylinder”

“Key-operated window locks on all accessible windows”

If your current hardware doesn’t meet the stated standard, your theft cover could be reduced or invalidated in the event of a claim. Upgrading to BS-rated locks and anti-snap cylinders is usually straightforward and relatively inexpensive compared to the risk of non-compliance.

Relevant British Standards for locks and cylinders

The most frequently cited standards include:

BS 3621 – thief-resistant key-euro operated mortice locks and rim locks suitable for external doors. Recognised by insurers and often accompanied by the British Standard Kitemark.

BS 8621 – similar to BS 3621 but with keyless egress from the inside (e.g. thumbturn), often used for doors on escape routes in flats and HMOs.

BS 10621 – locks where the deadlock can be activated by key from outside only, commonly used where additional security is needed.

TS 007 and SS312 – often referenced indirectly in insurer guidance for “3-star cylinders” or “anti-snap cylinders.”

When choosing products from our home security range, look for mention of these standards and, where applicable, the Kitemark or Sold Secure logos in the product descriptions.

Landlords, HMOs and fire safety considerations

For rented properties, particularly Houses in Multiple Occupation (HMOs), additional regulations and local authority requirements apply:

Locks on bedroom doors often need to allow escape without a key from the inside (e.g. BS 8621 thumbturn locks) to comply with fire safety guidance.

Entrance doors to flats in multi-occupancy buildings usually need self-closing devices and fire-resistant construction, along with keyless egress from the inside.

Landlords have an obligation under the Homes (Fitness for Human Habitation) Act 2018 to provide secure doors and windows – defective locks can be considered a failure to provide a safe home.

When upgrading in rented properties, balance security with escape requirements. Thumbturn cylinders and locks are a common solution on exit doors, providing external key control while maintaining internal keyless escape.

Proving compliance to insurers

Insurers rarely inspect every lock, but in the event of a claim they may ask:

What type of locks are fitted and where

Whether they conform to the stated standards

For photographs or invoices as evidence of upgrade

It’s good practice to:

Keep receipts or invoices for new locks and cylinders

Note down the standards (e.g. “BS 3621”, “TS 007 3-star”) and brands (e.g. Yale, ERA, Avocet) of the products installed

Ensure everyone in the household knows how to use the locks correctly, including fully engaging multipoint locks by lifting the handle and turning the key

Upgrading existing hardware

Whether you’re a trade installer or a homeowner improving security, upgrading existing door and window hardware is often a better investment than adding more alarms or cameras. Locks and cylinders are your first line of defence.

Prioritising your upgrades

If budget is limited, focus on the highest impact improvements first:

External door cylinders – replace basic euro cylinders with TS 007 3-star or SS312 Diamond-rated anti-snap cylinders. This is usually the most cost-effective upgrade.

Front door lockset – on timber doors, ensure you have a BS 3621 mortice deadlock or sashlock, and consider upgrading the rim nightlatch to a British Standard model if it’s old or basic.

Door handles and security furniture – on PVCu/composite doors, upgrade to TS 007 2-star security handles which protect the cylinder from attack. Used with a 1-star cylinder, this gives a cumulative 3-star rating.

Accessible windows – make sure all ground floor and easily reachable windows have working, key-operated locks.

Letterplate security – fit a letterplate restrictor or internal hood to prevent fishing for keys and operating thumbturns through the letterbox.

You’ll find suitable products across our home security, euro cylinders and door and window hardware categories.

Upgrading PVCu and composite doors

Most PVCu and composite doors use a multipoint locking mechanism with an external euro cylinder:

Step 1 – assess the existing cylinder

Check if it has any security markings (e.g. TS 007 star rating) or if it appears to be a basic, unbranded unit.

If it protrudes more than 3mm beyond the handle backplate, plan to replace it with a correctly sized cylinder.

Step 2 – measure and select a replacement

Follow the measuring method described earlier (from the centre of the fixing screw to each end) and choose a cylinder with appropriate internal/external lengths.

For high security, go for a 3-star or SS312 Diamond anti-snap cylinder from a recognised brand like Avocet, Yale, ERA or Mila.

Step 3 – consider upgrading the handles

Old or flimsy handles can flex under attack, exposing the cylinder.

TS 007 2-star security handles use hardened backplates and cylinder shrouds to resist snapping and drilling.

Trade tip: When replacing multipoint lock gearboxes or full strips, ensure you match the backset (commonly 28mm, 30mm, 35mm, 45mm) and the PZ (the distance between the handle spindle and cylinder centre – often 92mm) to the existing unit to avoid major door modifications.

Upgrading timber doors

Traditional timber front doors (common in UK terraces and older properties) often benefit from a combination of upgrades:

Mortice lock – ensure you have a 5-lever BS 3621 deadlock or sashlock. If your current lock isn’t Kitemarked, consider upgrading to a British Standard model.

Rim nightlatch – upgrade to a BS 3621 rim nightlatch for additional security and automatic latching. Brands like Yale and ERA offer high-security nightlatches with reinforced cases and cylinder protection.

Hinge bolts – especially on outward-opening doors. Hinge bolts (dog bolts) engage the frame when the door is closed and help prevent the door being forced off its hinges.

Door viewers and chains – add a wide-angle viewer and a strong chain or limiter to verify callers before unlocking.

DIY guidance:

When fitting a new mortice lock, carefully mark out the case size with a template or the lock body itself.

Use a sharp chisel and drill in stages to avoid splitting the door edge.

Ensure the lock is centred thickness-wise in the door and that the forend sits flush with the edge.

Fit the strike plate securely into the frame, with sufficient depth for the deadbolt and, if applicable, the latchbolt.

Aluminium and sliding patio doors

Older aluminium sliding doors and some basic PVCu sliders can be vulnerable to:

Being lifted off their tracks

Forcing simple latch-only mechanisms

To upgrade security:

Fit anti-lift devices – these can be metal plates or brackets on the frame and head that prevent the sash from being lifted high enough to clear the track.

Add auxiliary locks – surface-mounted patio door bolts that engage into the frame or track provide additional locking points.

Upgrade the main lock – where possible, replace basic centre latches with multi-point locking gear compatible with the existing profile.

For hinged aluminium doors, the same principles as for composite/PVCu apply: upgrade to anti-snap cylinders and, where possible, use security handles or cylinder guards.

DIY vs professional installation

Many upgrades, such as replacing euro cylinders and window handles, are well within the reach of competent DIYers with basic tools. However, consider professional help when:

The door or window is badly misaligned, rubbing or difficult to close – this may require specialist adjustments (e.g. toe-and-heeling glazed doors).

You are replacing multipoint lock gearboxes in older doors where the brand or type is unclear.

Fire doors or escape routes are involved, particularly in flats and HMOs; incorrect hardware could compromise fire safety and regulatory compliance.

Tradespeople and locksmiths will often carry a stock of common sizes and brands (Maco, Mila, ERA, Yale, Avocet, etc.) and can quickly identify and fit suitable replacements. For DIY customers, our detailed product listings and measuring guides in the home security section are designed to help you make the right choice first time.

Maintaining hardware for long-term security

Even the best hardware will underperform if neglected. Simple routine maintenance helps keep doors and windows secure:

Lubrication – apply a light lubricant (e.g. silicone spray or graphite for cylinders, not heavy oil) to moving parts once or twice a year. Avoid spraying WD-40 or similar into cylinders as a long-term solution; it can attract dirt.

Check fixings – periodically tighten loose handle screws, strike plates and keeps. Loose hardware reduces both security and alignment.

Inspect weather seals and alignment – if doors or windows drop, adjust hinges or keeps so that locking points engage fully without excessive force on the handle.

Replace worn or damaged items promptly – wobbly handles, keys that are difficult to turn, or locks that only work when “jiggled” are early warning signs.

Properly selected, installed and maintained hardware from our home security and related categories will help protect your home, comply with insurance requirements and provide peace of mind for years to come.