Reglazing a Window

This guidance will help you to reglaze a window, refitting plain or leaded glass in a period house.

If the window is leaded glass, if you try to remove the glass, you will probably find that the outer lead, around the window, will have perished. It will therefore be fragile and you will have to replace it. Please read our advice on this.

When replacing a pane, wear thick gloves. Chip out the glass, and the putty. Paint stripper or household bleach can be used to soften the putty; apply it and then cover with clingfilm until the putty has softened.

Use pliers to remove the 'sprigs', the little nails holding the glass in.

Measure the opening, and subtract 3mm from the height and width. Try to get horticultural glass which has the imperfections similar to those of the original glass.

Prepare the putty by rolling it in your hands and form a rope. Press this into rebate of the window; feed it forward from your hand rather than pulling it back.

Place the glass into the window and press all round it. Tap the sprigs into the wood; protect the glass from the hammer with a piece of thick card. Make a second putty rope and press this around the edge. Dip a putty knife in water and smooth the putty to form a bevel.

Ideally do not paint the putty until one month has elapsed, overlapping onto the glass by 1mm or so. If painting has to be done quickly, wait till a skin has formed on the putty - several hours.