Moving into a new home, starting or ending a tenancy and changing a shared household are sensible times to review access control. Even when every known key has been returned, it may be impossible to know how many copies were made and who still holds one.
Changing the lock does not always mean replacing the complete mechanism. On many doors, replacing the cylinder — the component into which the key is inserted — provides a new controlled set of keys. The right choice depends on the door, lock case, cylinder, protective escutcheon and the level of protection required.
When to review keys and locks
- You bought a home and received keys from the previous owner.
- You moved into rented accommodation previously occupied by other tenants.
- A tenancy ended and new occupants will move in.
- A housemate left or no longer has permission to enter.
- A relationship ended or staff, contractors, carers or cleaners changed.
- A key was lost or stolen, particularly when it can be linked to the address.
- Copies were given to relatives, neighbours or contractors and are no longer accounted for.
- The key sticks, the cylinder is loose or the lock shows wear or tampering.
The aim is not to create unnecessary concern. It is to restore a simple rule: know how many keys exist and who is authorised to use them.
Buying a home
Previous owners may return every key they know about, while older copies may remain with relatives, neighbours, tradespeople or service providers. A replacement cylinder starts the new ownership period with a known set of keys.
The move is also a useful time to check whether the door closes smoothly, all locking points align and the cylinder does not protrude excessively. Poor alignment can strain a new lock and reduce its working life.
Rented accommodation
Review the tenancy agreement and agree any permanent alteration in writing with the landlord or owner. Clarify whether only the cylinder will be changed, whether the original part will be retained and how many keys will be supplied. This keeps a clear record for everyone involved.
Landlords preparing a property for new tenants can use the handover to assess wear, establish a known key set and resolve lock problems before occupation.
Shared homes when a housemate leaves
Returning a key matters, but it cannot prove that no copy was made. Cylinder replacement may be appropriate when access permission has ended, there is conflict or the remaining residents cannot reliably account for copies.
Count and record the new keys. Do not label them with the full address. Where electronic locks or access codes are used, remove old credentials and issue individual codes rather than sharing one permanent code.
Lock and cylinder: what is the difference?
The lock is the mechanism fitted to the door. The cylinder is the key-operated component that activates it. Many European-profile locks allow the cylinder to be replaced without changing the whole lock case.
A complete replacement may be required for internal failure, damage, corrosion, major misalignment, incompatibility or a move to a different system. A professional assessment helps prevent the purchase of an incorrectly sized part.
Choosing a security cylinder
Correct measurement comes first. A cylinder that protrudes too far may be more exposed, while an incompatible size may not operate correctly. Depending on the door and budget, features may include drill, bumping, picking and extraction resistance, reinforcement, emergency function and controlled key profiles.
No single component makes a door completely invulnerable. Security depends on the door, frame, hinges, lock, cylinder, escutcheon, installation and everyday key management.
Lost or stolen keys
If a missing key can be associated with the property, replacing the cylinder prevents that key from continuing to operate the door. If keys were stolen, review remote controls, access codes, shared entrances and any other credentials on the same key ring.
If you are locked out, call before trying cards, wires or improvised tools. These can damage the lock, frame and door. Identification and evidence of legitimate access may be requested before an opening or replacement.
Moving-home checklist
- Count and identify every key received.
- Ask whether third parties hold copies.
- Test the door inside and outside without forcing the key.
- Check protrusion, looseness, alignment and wear.
- Decide who remains authorised to enter.
- Agree alterations in writing for rented homes.
- Confirm measurements and compatibility before choosing hardware.
- Record the distribution of new keys and protect any ownership card.
Shop advice and on-site service
Casa de Chaves Don Pedro's physical Lisbon shop provides advice on compatible cylinders, locks, protective escutcheons, electronic locks and key copies. Bring clear photos and call before visiting to confirm opening times and available options.
On-site lock replacement, cylinder changes, installation and repair are available across the active service locations shown on this website, subject to appointment or confirmed availability. Call with the door type, situation and location so the appropriate service can be discussed before travel.