Composite Door Security Specifications — What the Standards Mean and What to Ask For

The security of a composite door is determined by three elements: the cylinder, the locking mechanism, and the quality of the door-to-frame fit. All three must be correct for the door to offer genuine resistance to the attack methods used in the majority of UK residential burglaries. A composite door with a standard cylinder, however impressive its core and skin specification, is significantly easier to defeat than the same door with an anti-snap cylinder. Understanding what to specify — and what the various certification marks actually mean — is the foundation of a genuinely secure door installation.

The Anti-Snap Cylinder — the Most Important Security Upgrade

Lock snapping is the dominant forced entry technique on uPVC and composite doors in the UK — it accounts for more residential burglaries than any other single door attack method. A standard Euro cylinder can be snapped in under 30 seconds using a tool available online. The snap attack works by applying rotational force to the exposed cylinder end, causing it to fracture at the weakest point and allowing the lock to be turned directly. An anti-snap cylinder has an engineered break zone beyond the shear line — when the cylinder snaps, the break occurs in a position that leaves the lock mechanism intact and the door unopenable. Brands certified to TS007 3-star standard (Ultion, Avocet ABS, Yale Superior, and others) have been tested against this attack method.

"Lock snapping remains the most common method of composite and uPVC door forced entry in the UK. The attack is fast, quiet, and requires no specialist knowledge. An anti-snap cylinder certified to TS007 3-star makes this method ineffective at the cost of a £30–£80 cylinder upgrade. This is the single most cost-effective security improvement available on any new or existing composite door installation."

— Secured by Design — Residential Door Security Standards

TS007 3★

The cylinder certification standard that confirms anti-snap protection

PAS 24

The doorset standard that tests the complete door, frame, and lock system

PAS 24 — the Doorset Standard That Matters

PAS 24 (Enhanced Security Performance Requirements for Doorsets) tests the complete assembled doorset — door, frame, glazing, locks, and hardware — against a series of physical attack methods. A PAS 24-certified composite door has been tested against manual attack, crowbar attack, glazing attack, and cylinder attack (using a cylinder that also meets TS007). Building Regulations Part Q now requires that replacement external doors in new dwellings achieve PAS 24 or equivalent — it is worth confirming that any composite door being quoted meets this standard, not just through certificate claims but by asking the installer for the specific door model's test certification.

Secured by Design Accreditation

Secured by Design is a police-backed accreditation scheme for products and developments that meet certified security standards. A composite door bearing the Secured by Design mark has been independently assessed against physical security standards and meets the requirements of the scheme. Insurance companies increasingly recognise Secured by Design products — some policies offer premium reductions for properties with SBD-accredited door and window installations. The scheme's product directory lists certified door manufacturers, allowing comparison before purchase.

"Secured by Design certification is the gold standard for residential door security in the UK. It is not a marketing claim: it is an independently assessed accreditation based on physical testing against real attack methods. A homeowner who specifies a Secured by Design composite door from a Secured by Design registered installer has done everything that is reasonably achievable to secure that entry point."

— Secured by Design — Homeowner Guidance

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