Thinking the door is locked
There is a common misconception among people with uPVC or composite doors that require the door to be opened from the outside with a key, not the handle, that the door is locked when you pull the door closed. If you have a system like the this there’s a fairly good chance that the key is just working the latch mechanism, no different to that on your internal doors…
For most uPVC doors to be locked, the locking handle must be lifted vertically until the locking parts have moved into their respective recesses. Once they are fully extended the key can then be turned full circle, locking the system off. Only at this point, is the door locked.
Forcing the key
If you are having to force the key, then there is something wrong. Either your key is slightly off alignment, or the parts are worn and need replacing. To continue to use a system that you can feel is not right, will one way or another result in failure of the system.
Much better to call out a locksmith to check the locking system and pro-actively change it (but only if required!) than to end up in a situation where you need to call out an emergency locksmith.
Forcing the handle
Any handle you have on a uPVC door that requires to be lifted to lock, should be able to be opened and locked by Granny Jones 85 down the road. If you think your handle is too stiff for her to use, then IT IS too stiff. This can have several detrimental effects on your locking system, resulting in extreme wear and tear that will cause the system to fail years sooner than it should. 9 times out of 10, this is a simple fix for a locksmith or uPVC repair specialist and can be done with minimal disruption.
A phrase I use to let customers know if their lock could be on the way out, is “does it Stick, click or slip”