How to toe & heel a window or door

Toe and heeling is the glazier's trick that keeps sashes and doors square: the glass unit is packed diagonally inside the frame so it works as a rigid brace. Every window and door we make is toe and heeled in the factory, but transport, glazing on site or years of use can mean it needs doing again, and it's the first fix for a door that has dropped.

It applies to our made-to-measure uPVC windows and uPVC door sets.

1. 1

   Spot the signs of a dropped sash or door

   Glass doesn't flex, so a properly packed unit acts as a rigid brace that holds the sash or door slab perfectly square. When the packing settles or was never right, the slab “drops” away from the top hinge: the gap gets wider at the top lock corner, the bottom lock corner starts catching the frame or threshold, and you find yourself lifting the handle harder and harder to lock it. That's the cue to toe and heel.

2. 2

   Remove the glazing beads

   Working from inside, push a glazing paddle or stiff filling knife into the joint between bead and frame at the middle of a long bead, and twist. The bead pops out of its groove. Slide along and free the ends, then repeat for the others, leaving the top bead until last so the unit stays held. Lay the beads out in order so each one goes back where it came from. Don't use a screwdriver against the glass, and never force anything against the unit edge.

3. 3

   Check the bridge packers under the glass

   With the beads off you can see how the unit sits. Its weight must rest on flat bridge packers that straddle the drainage channel in the bottom rebate, never directly on the uPVC, and never blocking the drain holes. Packers should be at least as wide as the glass unit is thick (typically 28mm) so both panes are supported. If they're missing or askew, sit the unit properly before you go any further.

4. 4

   Pack the heel: the bottom hinge corner

   Find the corner at the bottom of the hinge side. That's the heel. Slide flat plastic glazing packers (they come in 1-6mm thicknesses) into the gap between the edge of the glass and the sash, snug but not forced. This anchors the bottom of the diagonal brace you're about to create. Only ever use plastic glazing packers, never wood, metal or coins.

5. 5

   Pack the toe: the top lock corner

   Now the diagonally opposite corner: the top of the lock side, the toe. Have a helper lift the lock side of the sash or slab until the gap around it looks even. A glazing paddle under the glass edge (never a screwdriver) gives fine control. Slide packers into the toe corner until they're snug. The glass now props the slab square: its weight travels down the diagonal from toe to heel and into the hinges.

6. 6

   Check the operation before you refit anything

   Open and close it a few times. The margin around the sash or slab should be even all round (roughly 3-5mm), the lock should engage without lifting or slamming, and nothing should rub. Too tight or still dropped? Swap packers for a thinner or thicker size. Don't stack force into the glass edge, as over-packing stresses the unit and can crack it or pop its seal.

7. 7

   Refit the beads

   Refit the beads in the reverse order you removed them: locate both ends into the corners first, then tap the middle home with a nylon or rubber mallet until it snaps into its groove, never a bare hammer, and never strike the glass. Shorter beads first, longest last. Give everything a final open, close and lock, and you're done.