Hollow metal steel doors and frames are built to last decades — but rear doors, warehouse man doors, stairwell doors and mechanical room doors eventually reach the point where repair no longer makes sense. Rust eats through the bottom of the frame, impacts dent the door out of shape, forced-entry attempts bend the jamb, and the hardware stops working. This guide explains how hollow metal doors and frames are built, the signs it is time to replace them, how a proper replacement is done, and what to think about for fire-rated and high-security openings in GTA commercial buildings.
How hollow metal doors and frames are built
The door
A hollow metal door is made of two steel face sheets over an internal core — honeycomb, polystyrene, polyurethane, or steel stiffeners — with reinforcements built in where hinges, locks and closers attach. The gauge of the steel (its thickness) and the core determine strength, insulation and suitability for fire ratings.
The frame
Hollow metal frames come in two main types:
- Knock-down (KD) frames are shipped in pieces and assembled on site, often installed into existing drywall openings.
- Welded frames are welded into one unit at the factory and set during construction, usually anchored into masonry or steel stud walls. They are stiffer and more durable on high-traffic and high-security openings.
Hardware preparation
Doors and frames are prepared (“prepped”) for specific hinges, locks, strikes, closers and exit devices. When replacing, matching or updating these preps matters — otherwise the new door will not work with your hardware.
Signs your steel door or frame needs replacement
Rusted frame bottoms
The bottom of exterior steel frames sits in salt, slush and standing water every winter. Over the years the steel rusts from the inside out until the jamb is perforated or detached from the floor. A rusted frame no longer holds the door square or secure.
Doors rusted through or delaminating
The bottom edge of the door skin often rusts through first, and face sheets can separate from the core. Once the skin has failed, the door loses strength and insulation.
Impact damage
Pallet jacks, carts, forklifts and vehicles dent doors and bend frames. A badly dented door may drag, bind or no longer latch.
Forced-entry damage
Prying at the lock side bends the frame stop and the jamb and can tear the strike out. Even after repairs, a bent frame often leaves a gap that invites the next attempt.
Hinges tearing out
When hinge reinforcements fail, screws tear out of the door edge or frame, and the door sags. Repeated re-screwing rarely holds for long.
Doors that never seal
If a rear door lets in drafts, water and light even with new weatherstripping, the door or frame is usually out of square.
Repair or replace?
Many steel door problems are repairable — re-hanging the door, replacing hinges and closers, straightening minor dents, or replacing a section of a rusted frame. Replace the door, the frame or both when:
- The door skin is torn, rusted through or delaminated.
- The frame is twisted, bent or rusted along most of its length.
- The opening has been forced repeatedly.
- Internal reinforcements have failed and hardware will not stay secure.
- A fire-rated opening is damaged and can no longer perform as rated.
For smaller repairs see hollow metal and steel door repair; for frame-only issues see door frame repair.
How a proper replacement is done
- Survey and measurement. Opening size, wall type, swing, handing, hardware and any fire rating are recorded. Older buildings often have non-standard sizes.
- Ordering the right door and frame. Gauge, core, fire label, and hardware preps are specified to match the building’s needs.
- Removal. The old door and, if required, the frame are removed while protecting the surrounding wall and floor.
- Setting the frame. The new frame is set plumb, level and square, anchored properly to the wall and floor, and grouted or fastened as the wall type requires.
- Hanging the door and hardware. Hinges, lock or exit device, closer and any electrified hardware are installed and adjusted.
- Sealing and finishing. Weatherstripping, sweep and threshold are added on exterior doors; the frame is caulked and finished.
- Testing. The door must swing freely, close and latch on its own, lock correctly and seal evenly.
Fire-rated steel doors and frames
Stairwells, corridors and some service rooms require fire-rated door assemblies. Both the door and the frame carry labels, and the hardware — hinges, closer, latch or fire exit device — must be suitable for fire doors. A replacement must maintain the rating of the opening: do not mix unlabeled frames with labeled doors, and make sure the door self-closes and latches. See fire door inspection and repair.
Security upgrades when you replace
- Heavier gauge doors and frames for rear and laneway doors.
- Welded frames on high-risk openings.
- Latch guards to block prying at the lock edge.
- Non-removable hinge pins or security studs on outswing doors.
- Vertical rod exit devices on pairs of doors — see our panic bar guide.
- Quality cylinders and rekeying — see commercial lock repair.
Winter and salt: protecting your new door
Most frame failures we see in the GTA start at the bottom of the frame where salt and water sit. To protect a new door and frame: keep snow and slush cleared from the threshold, rinse salt away during thaws, touch up any scratched paint before rust starts, and make sure the threshold and sweep keep water from pooling. A little maintenance adds years to the life of the opening.
Hollow metal door and frame replacement across the GTA
We replace steel doors and frames throughout the GTA and surrounding regions, including Hamilton, Kitchener, Mississauga, Brampton and Vaughan. See also commercial door replacement and commercial door installation.
Frequently asked questions
What is a hollow metal door?
A hollow metal door is a steel door made of two steel face sheets over an internal core, with reinforcements for hardware. It is the standard door for commercial rear exits, stairwells and service areas.
Can you replace a steel door without replacing the frame?
Yes, if the frame is solid, square and prepared for compatible hardware. If the frame is rusted, bent or damaged, replacing both gives a better result.
How long does a steel door and frame replacement take?
Once the door and frame are on site, a single opening is usually completed in one visit. Custom sizes and fire-rated assemblies may need to be ordered first.
Can a rusted frame bottom be repaired?
Often the rusted section can be cut out and replaced. If the rust extends further up the jamb, a full frame replacement is more reliable.
Do fire-rated openings need labeled doors and frames?
Yes. Fire-rated openings require labeled doors and frames with suitable hardware, and the door must self-close and latch.
Get a quote
Call Commercial Door Repair Ontario at 647-931-0097 or request a quote for hollow metal door and frame replacement anywhere in the GTA.