The frame is the fixed structure of an armoured door: the steel part anchored to the wall, the part that the leaf, the section that opens, hinges onto.
It is the backbone of the armoured front door, the part that does not move, and on its own it decides much of how secure your entrance really is.
When you turn the key, the bolts come out of the leaf and slide into the frame: if the frame is weak or poorly anchored, all the strength of the leaf counts for little.
The difference between frame and subframe
The two are often confused, but they are two different things that work together.
The subframe is the casing that is built into the opening first, as the base on which everything else is fixed.
The frame proper is the load-bearing structure of the door, fixed on top of the subframe: it is what holds the leaf and houses the bolts.
The general terminology of doors and windows is also covered in the entry door on Wikipedia.
What the frame is for
The frame does three jobs, all of them important.
It holds the leaf through the hinges, keeping it square over time.
It houses the bolts in its keepers, turning the locked door into a single block with the wall.
It transfers the loads to the masonry, so that pushes and prying attempts are not all taken by a single point.
Why the frame is decisive for security
A strong, well-anchored frame is what stops anyone from levering the door off its mountings, one of the most exploited routes when the leaf is solid but the surround is weak.
That is why on serious doors the frame is made of steel and is fixed to the wall with numerous anchor lugs set into the masonry, not with a few wall plugs.
The thickness and the keepers that hold the bolts matter just as much: that is where the door truly resists a forced entry.
Why frame and installation go together
Even the best frame achieves little if it is fitted out of true.
A frame installed plumb and square spreads the loads evenly and lets the bolts and hinges work properly, whereas one that is out of square makes the leaf rub and weakens the seal.
This is why the quality of the frame is also decided in the armoured door installation, where the skill of whoever fits it counts.
The frame in Ariete armoured doors
On Ariete doors the frame works together with the leaf and with locking points distributed on every side, so resistance is not concentrated on the lock side alone.
To understand how the various parts fit together, from the frame to the bolts, you will find everything in how an armoured door is made.
Conclusion
The frame is the silent half of the armoured door: you do not notice it the way you notice the leaf, but it is where the door ties into the wall and withstands forced entry.
It is the frame that houses the bolts and stops the door from being levered off, even when the leaf is sturdy.
Three things make the difference between a frame that holds and one that gives way: the steel it is built from, the anchoring with lugs set into the wall and the plumb and square installation.
So when you are assessing a front door, do not stop at the leaf or the lock: ask how the frame is built and how it is fixed, because it is exactly half of your security.
And remember that fitting a new door onto an old frame almost always means giving up part of the protection, because the frame is part of the product and not just an accessory.
Frequently asked questions
It is made of steel, because it has to hold the weight of the leaf and resist prying attempts. Its quality depends on the thickness and on how it is anchored to the wall.
It is almost never worth it. The new frame is part of the door’s security, and fitting a new door onto an old frame means giving up part of the protection: it should be assessed by a technician.
The subframe is built in first as the base, while the frame is the load-bearing structure fixed on top of it, on which the leaf works. They work together but have different jobs.
Both matter. A strong leaf on a weak frame can be levered off, so the door should be assessed as a single system, frame and anchoring included.