Bar the Door

You touch a closed door, and it becomes locked and barred for the duration.   Otherwise, it is impassable until it is broken or the spell is dispelled or suppressed. Casting knock on the object removes either the barred or the locked effect; two castings of the spell would be required to remove both effects. A dispel magic will remove both effects and allow the door to be opened. If only the barred effect is removed, the lock can be picked; otherwise it can only be opened by breaking. 

While affected by this spell, the object is more difficult to break or force open; the DC to break it or pick any locks on it increases by 10 and the AC of the door increases by 2.