Window Reglazing: How to Restore Old Windows in Your House

Sure, replacement windows are a fast and efficient way to maintain your home’s windows. But there are times when restoration is the only sensible alternative. Many homeowners are proud of their old bungalow home’s architectural character, and wouldn’t dream of putting replacement windows in. Even so, drafty winter nights and high energy bills can get old real fast. That’s when it’s time to consider reglazing your windows.

To reglaze, you’ll need to remove the old putty around the glass. This usually entails stripping away some or all of the layers of paint that may have accumulated over time on your window. It’s possible to just sand way the paint locally in order to get the old glazing putty off, but as long as you’ve removed the sash and have it in front of you to work on, you may as well strip all of the paint off. This will have the added benefit of making it easier to open old windows usually have so many paint layers on them that they no longer slide freely in their frames. Plus you can apply some good wood-preserving primer before re-painting.

Use caution if you are using a heat gun to help strip paint from the sash you risk the glass breaking from sudden expansion. For this reason also, wear eye protection and gloves during the process. A heat gun will also help in the next step, removing the old glazing putty, but many restoration specialists advise against it, especially if you wish to use your old glass.

When removing the glass, watch for metal glazing points that hold the glass in place. These should be taken out. The glass panes can then be removed for cleaning. Also excess putty can be detached from the sash.

Sashes should be sanded, patched, and primed with an oil-based preservative primer. When the primer is dry, and prior to reinstalling the glass, lay a bead of oil-based glazing putty around the rabbet to seal and cushion the glass. Next place the glass firmly in the window and replace the glazing points. Now you can apply the final glazing compound. Knead the compound for a minute, and roll it in your hands to create a bead of glazing putty.

Place the compound bead along the edge of the glass, then using a stiff putty knife, flatten it against the sash and window. Try to do this in one smooth motion, and avoid going back and forth over the compound bead. Use the edge of the putty knife to remove the excess.

Your reglazed window can be repainted on the inside and outside once the putty has set has set, which is usually after about 48 hours.