Solution: get hold of a sledgehammer, right click on the doorframe and select the "destroy" option.
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so i placed a doorframe in the wrong place, it seems you can break down other placed wall components by smacking them with a hammer if you place them wrong, but the door frame has no hitbox to my weapons, however i can crash into it with a vehicle.. though i really dont want to break my only vehicle by smacking it into a wall.
I tried with a few items to hit this object but to no avail.. if anyone has any ideas please let me know