Restore traditional single-pane windows

While the traditional single-glazed sash is becoming rare, there are still a lot of wood windows out there worth repairing. Single-glazed windows are popular in heritage homes, sheds, garages and cottages. Window panes need reglazing when there is obvious cracking, chipping, gapping or other deterioration of the putty, allowing water to migrate into the sash. If tapping on the glass produces a rattle, the pane is due for reglazing. Thankfully, the skills are not difficult to master.

It’s best to work with the window in an upright, vertical position, just as it is installed in the jamb. Often you can reglaze a window in place or rig up a glazing easel. This set-up can be as simple as an appropriately sized sheet of plywood held upright at an angle by some triangular brackets. Screw a scrap of wood for a ledge to rest the sash on and clamp, or screw the easel to a sturdy work table.

Deglaze, before reglazing

Removing old putty is the most time-consuming and difficult part of the job, but there are a few tools and techniques to help. The best way to get glazing compound out of the rabbet is with a chisel at least 1″ wide, and you have to keep it sharp.

Begin by holding the chisel perpendicularly to the glass and in line with the edge of the rabbet. With one hand, hold the tip of the chisel between your thumb and forefinger, with the bevel up, resting your hand against the sash, and apply pressure while pivoting the tip in a circular paring motion. Work along the rabbet, chipping out the putty, aiming for the seam between the putty and the glazing rabbet. Stop to resharpen the chisel when it stops cutting effectively.

Glazing points can be removed with a putty knife or chisel, by wiggling them out gently. Tiny brads often secure leaded panels and can be removed with needle-nose pliers.

After removing the glass, clean up the rabbet by scraping out any extra putty. Painting a prime coat of boiled linseed oil on the bare wood of the rabbet can help the putty adhere well without drying out. A coat of oil-based exterior primer also does the trick.