Replacing a Pane of Glass

Replacing a Broken Window

  • The first step is to remove the broken pane. A good idea is to liberally apply masking tape over the whole pane so that the larger pieces are kept together. Then, spread out a large sheet of plastic on either side of the pane – inside the house and outside, if it’s a window that you are sorting out; small shards of glass will fall on the plastic which you can then roll up and dispose of.
  • Next, remove the old putty from the window frame with a craft knife, putty knife or wood chisel. Make sure that you remove every trace of the old putty.
  • Remove all the glazier’s points – small metal triangles driven into the frame underneath the putty to hold the glass in place – as you remove the putty.
  • Apply a heavy coat of linseed oil to the frame to help keep the oil in the putty from drying out. Saturate the wood and you will find that the new putty remains pliable and lasts much longer.
  • Now run a very thin beading of putty, about 2-3mm or so, completely around the frame where the new glass will be set, as a cushion for the glass.

Installing the New Pane

  • Insert the new windowpane into the frame carefully. Press it down firmly and, still holding it in position with one hand, insert a glazier’s point on each side to secure the pane firmly in place.
  • Insert additional glazier’s points at 100mm intervals along each edge.
  • Putty should have the consistency of rather dry, thick dough when it is applied. Thin it down with the manufacturer’s recommended thinner if necessary.
  • Knead the putty until it is completely pliable and free of lumps, roll it into pencil-size strips and apply the rolls around the pane.
  • Once you have completed applying the putty, smooth it with a clean putty knife using long, even strokes. The putty should end up with a smooth, even surface at an angle of about 30-45° to the glass. It should not show from the inside of the window.
  • Once you are satisfied, run the knife around the inside of the frame to remove excess putty and to make a clean edge.

Shopping List

  • Masking tape
  • Large sheet of plastic
  • Craft knife, putty knife or wood chisel
  • Linseed oil
  • Putty
  • Glazier’s point
  • Glass, cut to size

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