The leaf is the guest, the frame is the host

Call us out to a door problem and the fault is nearly always in the frame. "The leaf has dropped" usually means the frame has moved. "The key won't turn" usually means a keep plate has shifted. "It rubs" usually means the frame is out of square. The leaf stays as it was manufactured; the part attached to the building is the part that moves.

A frame is a perimeter assembly of formed steel profiles with three jobs: carrying the leaf through the hinges, receiving the lock bolts, and closing the gap to the wall.

Profile section tells you everything

Cut through a frame profile and the shape explains the whole door. There are three zones: the legs that bear on the wall, the rebate the leaf closes into, and the face the architrave meets. The number and angle of the folds between them set the stiffness. More folds produce a stiffer profile from the same gauge, which is why "how many millimetres" is only half the question — ask how the profile is formed as well.

Depth against wall thickness

Frame depth cannot be chosen independently of the wall. Too shallow and bare wall shows beside the finished door while the architrave sits over a void. Too deep and the frame projects past the wall face.

  • Apartment doors use a standard depth, with extension profiles for unusual walls.
  • Building entrance and villa frames are adjustable between 20 and 24 cm, which covers thick walls and external insulation layers.
  • Plasterboard openings need structural framing behind the frame; no profile, however stiff, holds in a board alone.

Wall build-ups differ by country, so this is the detail most often missed on export orders. Send wall thickness in centimetres with the material.

Anchoring: foam carries nothing

The frame is fixed at several points per side with anchors suited to the wall material, more closely spaced on the hinge side where the leaf weight lands. The usual shortcut — two fixings and polyurethane foam for the rest — fails, because foam insulates and fills but does not carry load. It softens and the frame slowly works loose.

Before fixing, the frame is squared and the diagonals measured equal. Two or three millimetres of difference makes the leaf rub, and hinge adjustment will not correct it afterwards.

Keep pockets and reinforcement

The pockets the bolts enter are the most heavily loaded part of the frame. In production they are machined before welding, with backing plates behind them. Pockets cut on site weaken the section. An unreinforced keep plate reduces even a good lock to average performance, because under force the load lands on thin sheet and it bends.

Hinge blocks are welded, not screwed; screwed blocks develop play and that is how a leaf starts to sag. Hinge-side security pins need their own pockets, which matters more as leaf weight rises — as across our building entrance doors.

Architrave

The architrave closes the transition between frame and wall, and its width affects both appearance and tolerance. A narrow architrave gives a modern, slim line but forgives nothing in a crooked wall. A wide one saves the day in older buildings by covering plaster deviations. Apartment doors commonly use around 10 cm, which is why a 90 × 200 cm clear opening finishes at roughly 108 × 210 cm overall.

Can you keep the frame?

A fair question when replacing a door. If the frame is square, firmly anchored and free of corrosion, changing only leaf and hardware can cut cost — but hinge axis, lock axis and thickness all have to match, and that rarely aligns. If the frame moves, has rusted or sits out of square, replace both.

Models built to standard sizes usually drop into existing openings; start from the 90 × 200 cm clear reference for apartments. Pattern changes do not change the frame design, so sheet panel doors and the decorative ranges share the same frame family. Send a photo of your current frame with the wall thickness and we will tell you whether it can stay before quoting.