Repairing Leaded Light Windows

Repairing Leaded Light Windows

Lead Lights, the stained glass sometimes found in or above doors and windows in older houses, can seem difficult to repair if one of the small sections of coloured glass gets cracked or smashed. In reality, replacing the small panes of glass is a fairly simple, if slightly fiddly, job.

The main problem you might encounter is finding a local specialist glass supplier who can provide a replacement piece. It is worth checking this out before you take out the cracked glass so you know if you need to consider alternative solutions.


Step 1 – Removing the cracked glass

Traditional lead lights are constructed of small, shaped glass cutouts, held together by lead bars that have a groove cut into them. To remove a section of glass, you need to take a small chisel and insert it under the lead lip that holds the glass and bend it outwards. Do this all the way around the shape, until the glass drops out.

The corners may be soldered to give the window more strength. If this is the case, you will need to cut through the solder using a sharp knife. When it comes to putting the replacement glass into the frame, these cut corners can be bent back into shape and then glued using a two-part acrylic glue.

Glazing Tool Kit

Step 2 – Creating a template

To be able to get a replacement piece of glass that will fit the hole, you will need to make a template out of cardboard that fits in the gap. You can then take this, along with a piece of the original glass, to a specialist glass merchant.

Hopefully they will be able to match the colour and make a replacement. If you are having real trouble finding replacement glass, you can get the shape cut in clear glass and then use glass paint to colour it.

Step 3 – Fitting the stained glass

Once you have your replacement piece, you need to fit it back into the lead light. Before you do so, apply a bead of silicone sealer around the inside of the folded lead strip. This will ensure that the new glass does not rattle when it is in place (it can be difficult to get replacement sections to fit tightly).

Press the glass into place and carefully fold the lead edges back into position to hold it. Remove any sealant that is squeezed out with a cloth and make sure that the lead it flat and almost flush with the surface of the glass.

Repairing Leaks in Leaded Lights

As a leaded light window ages, you may find that leaks can appear between the small panes of glass. The easiest way to deal with small leaks is to seal the edges of the lead strips using a exterior-grade polyurethane varnish. Marks the leaks using a wax crayon during bad weather, so that you can identify and treat the leak when the rain stops.

Using a small artists paintbrush, brush the varnish liberally along the edge of the lead strip where it meets the glass. Make sure you do this both on the inside and the outside of the glass.

Press the lead strips down firmly in that area (ensuring someone is supporting the window from the other side) and then wipe off any excess varnish with a clean cloth dipped in white spirit.