Mortice lock, backset and strike plate

Alongside the cylinder, the lock and the strike plate work together as one unit – relevant after damage or for a planned upgrade, rarely for a simple emergency opening.

A lock for a euro profile cylinder with latch and bolt. Whether a lock can be swapped depends on the backset and the centre distance (in flats often a backset of 55/60 mm and a centre distance of 72 mm; some doors also 92 mm). It is usually replaced after damage or for an upgrade – not with every opening.

The counterpart in the door frame for the latch and the bolt. It must match the bolt throw and the lock; a reinforced plate makes the door harder to lever open. Replaced only if damaged or as part of an upgrade.

The lock sits inside the door, and the cylinder sits in the lock. If the lock is faulty, the latch catches, the handle droops or the bolt is stiff. After a break-in the lock is often bent too. Then a new cylinder alone is not enough.

Often the lock is not the problem at all. Doors warp with heat and cold, and then the bolt no longer meets its counterpart in the frame properly. Often it is enough to adjust the strike plate in the frame. We check this before we suggest a new lock.

For a new lock to fit, two measurements are needed. The backset (Dornmaß) is the distance from the edge of the door to the centre of the handle. The centre distance is the distance between the handle and the cylinder. A photo of the open door from the side already helps us a lot.

The latch and the bolt engage in this plate. If it is loose or only fixed with short screws, the door is easier to force open. A stronger plate with long screws going into the masonry makes the door much more stable.

Lock and strike plate are not on the price list, because doors vary so much. We give you a fixed amount on the phone beforehand, based on a photo if possible.

There are locks for doors that open to the left and for doors that open to the right. Many locks can be converted, some can’t. Look from the side where you pull the door towards you: if the hinges are on the left, it is a left-hand door. We can see this straight away on a photo too.

The lock sits in a pocket that is milled into the edge of the door. In other words, it is set into the door. From outside you only see the forend (Stulp), the metal strip on the edge of the door, as well as the handle and the cylinder. It used to be different: with a rim lock, the whole lock sits in a box on the inside of the door. You can still find locks like this in some older buildings today.

In older houses, room doors often have a warded lock (Buntbartschloss) with a simple key that has a bit at the front. This lock is only meant to keep the door closed; it does not protect against burglary. If a lock like this is still fitted to a flat door, converting it to a lock with a euro profile cylinder makes sense. With old wooden doors, we check at the same time whether the door and frame are still solid enough.

Doors made of uPVC or aluminium often have a narrow frame made of profiles. A normal lock will not fit in there. Instead, a narrow-stile lock (Rohrrahmenschloss) with a short backset is used. On uPVC front doors, the main lock is often part of a multi-point locking system. Wooden doors, on the other hand, usually have a classic mortice lock with a larger backset. A photo of the door edge quickly shows us which type you have and saves a second trip.

If the handle hangs down limply, the cause is often the handle set and not the lock. Many handles have their own spring or are only held by screws that loosen over time. Carefully tighten the screws on the inside. If the handle stays loose, we check the handle set and the lock. Only then do we decide with you what needs to be replaced. Often the smaller part is the cause.

Some doors in a block of flats are fire doors or smoke doors, for example the doors to the basement or the underground car park. Special rules apply to them. The lock, the door fittings and the door closer must match the door’s approval. Do not alter anything there yourself, not even by fitting a different handle. Always clarify changes with the property management or the owner. If the work is possible, you get the price from us before we start.

A mortice lock works for many years without any trouble. Over time, however, springs and sliding surfaces wear out. Typical signs are a latch that comes back slowly, or a bolt that only extends fully when you push. A drop of oil hardly helps here, because the lock is hidden inside the door. If it gets worse, a new lock with the same dimensions is usually the clean solution.