Installing a hollow metal door frame involves assembling the frame components, securing them to the rough opening, and checking that everything is plumb, level, and square so the door operates smoothly. The process differs depending on whether you’re working with wood studs, steel studs, or an existing masonry opening, but the core steps are the same: assemble the frame, position it in the opening, anchor it, and verify your tolerances.
Parts of the Frame You Should Know
Before you start, it helps to understand the terminology you’ll encounter in any instruction set. A hollow metal door frame has three main structural pieces: two vertical jambs and a horizontal header across the top. One jamb is the hinge jamb (prepped with cutouts for hinges or pivots), and the other is the strike jamb (prepped to receive the latch hardware).
The throat is the depth of the frame, measured between the returns on either side. This dimension needs to match your wall thickness. The rabbet is the recessed area between the face of the frame and the stop where the door panel actually sits. The stop is the raised lip that the door closes against. On most commercial frames, the stop is integral, meaning it’s formed as part of the frame profile rather than added separately.
Tools You’ll Need
- Carpenter’s level (4-foot minimum, 6-foot preferred)
- Framing square
- Wood spreaders cut to the exact width of the frame opening
- Saw or chisel for removing shipping spreader bars
- File for smoothing any cut points flush
- Drill and appropriate fasteners for your wall type
- Shims (wood or metal)
- Tape measure
One important note from the Steel Door Institute: frames often arrive with metal spreader bars tacked across the opening to prevent damage during shipping. These are not installation spreaders. Remove them with a saw or chisel and file the attachment points flush before you begin setting the frame. Use wood spreaders cut to size instead.
Assembling a Knockdown Frame
Most hollow metal frames for retrofit or renovation projects arrive as knockdown (KD) frames, meaning the header and jambs ship as separate pieces that you connect on site. Welded frames arrive as a single unit and skip this step entirely.
Start by sliding the header into one of the jambs. Each connection point uses a tab-and-slot system where tabs on one piece insert into corresponding slots on the other. Position both pieces so they overlap the wall by about 1 inch. Then connect the second jamb to the open end of the header, again overlapping the wall by about 1 inch. Once both jambs are seated, bend the tabs at the top of the header outward to lock the joint. The most critical tab connections are at the rabbeted part of the frame, where the door will sit. Those tabs should be bent firmly into an outward position to create a rigid, flush joint.
Choosing the Right Anchors for Your Wall
The anchor type determines how the frame attaches to the surrounding structure, and using the wrong one is a common mistake.
Wood stud anchors have two steel tabs that fold over the face of the stud. You position the frame in the opening, fold the tabs around the stud, and fasten them with screws directly into the wood.
Steel stud anchors use a bent steel plate that butts up against the metal stud. Fasteners go through the throat of the stud to secure the frame. This design accounts for the thinner profile of steel framing.
Existing masonry anchors are designed for openings where block or concrete walls are already standing. These are sometimes called “punch and dimple” anchors. A tube and strap channel is welded to the frame at pre-punched locations in the soffit, and expansion bolts pass through these channels into the masonry. This allows you to install a frame in a finished wall without tearing anything apart.
Setting the Frame in the Opening
With the frame assembled and the correct anchors attached, position it in the rough opening. If you’re working with a welded frame, you may need a second person to lift it into place as a single unit. Slide the frame into the opening so the throat wraps evenly around the wall on both sides.
Insert your wood spreaders near the bottom, middle, and top of the opening to hold the jambs at the correct width while you work. This prevents the frame from bowing inward or outward as you tighten anchors.
Checking Plumb, Level, and Square
This is the step that makes or breaks the installation. Industry standards call for a nominal clearance of 1/8 inch between the door and the frame on all sides, and 3/4 inch of clearance at the sill (the gap between the bottom of the door and the floor). You won’t hit those numbers if the frame isn’t set precisely.
Use your level to check that both jambs are perfectly plumb (vertically straight). Check the header for level across the top. Then use your square to confirm that all corners are 90 degrees. A properly set frame will measure the same diagonal distance from the top left corner to the bottom right as it does from the top right to the bottom left. If those diagonal measurements don’t match, the frame is racked and needs adjustment before you anchor it permanently.
Shim between the frame and the rough opening as needed to achieve plumb and level. On uneven floors, shim under the low side of the jamb to bring it level rather than trying to trim the high side. Once the frame is shimmed and verified, secure the anchors to the studs or wall.
Dealing With Uneven Floors
Floors are rarely perfectly flat, especially in older buildings or masonry construction. The approach that experienced installers recommend is straightforward: always install the frame plumb, level, and square regardless of the floor condition, then address the gap at the bottom separately.
Shim the low side of the frame until both jambs read plumb and the header reads level. If this creates a visible gap between the bottom of one jamb and the floor, you can fill it with caulk or a threshold shim depending on the application. The priority is a frame that operates correctly. A door hung in a racked frame will bind, sag, or fail to latch properly, and no amount of hardware adjustment will fully compensate.
Securing and Finishing
Once all anchors are fastened and you’ve verified your measurements one final time, remove the wood spreaders. Check the frame width at the top, middle, and bottom to make sure it stayed consistent during anchoring. If any section has shifted, loosen the nearest anchors, re-shim, and re-secure.
For steel stud and wood stud installations, the drywall or sheathing typically gets installed after the frame, lapping over the returns to create a clean finished look. For masonry installations where the wall is already complete, caulk or grout around the frame to seal it against the wall surface.
Before hanging the door, run your hand along the rabbet to confirm the stops are straight and no anchor heads or bent tabs are protruding into the door space. Standard hinge hardware provides only 1/16 inch of clearance between the hinge leaves when closed, so even a small obstruction can prevent proper operation.