Would this be secure?

[Lukas125]

I have recently moved into a new house with two sets of upvc patio doors. I want to change to anti snap locks, but this means changing 4 cylinders, at a time when funds are limited.

If I just changed the lock on the door that opens first on each set, i would only need two new locks, but would this be secure? The doors interlock and bolt to the frame, so it would appear impossible to open the second door without the first being open?

 

[JohnD]

or you could add patio door bolts, top and bottom of each door. As you will be aware, Eurocylinders are not very secure, nor are plastic doors.

extra bolts will improve security both now and in future if/when you change the cylinders.