PART Q · Security
Part Q building regulations explained
Part Q concerns security in new dwellings, including relevant dwellings created by a material change of use. It addresses reasonable resistance to unauthorised access. The requirement is about the relevant doors and windows as complete assemblies, not just their locks.
Which openings matter
The guidance addresses relevant doors and easily accessible windows. Location and access matter, including openings that may be reached from adjacent structures.
Ask the designer to identify which openings require the relevant performance. A ground-floor window and an inaccessible upper-floor window may have different roles in the assessment.
How is performance demonstrated
Approved Document Q identifies recognised security performance routes, including PAS 24 and suitable alternatives supported by evidence. The product supplied must match the configuration covered by that evidence.
A different lock, pane or frame arrangement may change the verified assembly. Do not assume a certificate for a product range covers every variation.
Does Part Q apply to all old houses
It is not a universal retrospective requirement to replace every door and window in an existing home. Identify the work and whether it creates a new dwelling or otherwise falls within the applicable scope.
Improving an older home's security remains a sensible design choice even where this particular provision is not triggered.
What other requirements matter
Security measures need to work with fire escape, ventilation and accessibility. A secure opening that prevents the intended escape or ventilation function creates a different problem.
For example, review locking arrangements on an escape route rather than specifying security in isolation.
What should you retain
Keep product identification, relevant performance evidence and installation information. Check the delivered units and hardware against the approved specification before installation.
Agree substitutions with the designer. A similar-looking cheaper unit should not be assumed to provide the same security performance.