When you learn the different parts of a vintage window and how they operate, you can repair them to last for decades. It’s a simple, step-by-step process to replace broken sash cords, remove and replace broken glass and deteriorated window putty, and use epoxy for deteriorated wood repair. Repairing windows not only improves the appearance of a vintage house, but can increase energy efficiency.
Beyond the obvious function of letting in sunlight and ventilation, windows are an important architectural element that give a vintage home its distinctive character. Think of windows as the eyes of the house. Like human eyes, they differ in appearance; the number and type of panes, and the width of the sash, rails, muntins and mullions all affecting the look of the home. In addition to maintaining the original style, preserving vintage windows retains the old growth lumber used to construct them — wood that is tight grained and longer lasting than new wood you can buy today.
In double-hung windows, the most common vintage window type, both the top and bottom sash operate via a set of cords or chains attached to counterweights in the wall. The rope or chain moves over pulleys in the jamb. It is not uncommon for the upper sash to be painted shut. Originally the upper sash lowered to vent out rising hot air, and the bottom sash elevated to allow in cooler air. Casement windows are hinged on one side. Some large or decorative windows were always fixed in place.
If your sashes are deteriorated, you can use the same epoxy process we discussed in a previous article on siding repair. If the rails are rotted beyond repair, you can have new rails milled to match at a mill shop. You can greatly improve energy efficiency of vintage windows by adding weather stripping and storm windows, or by replacing the single glass panes with thermo-pane glass in the existing frame.
Broken sash cords or chains are a common ailment of double-hung windows. Evidence of broken cords includes a sash that feels heavy to lift, slams down after opening or you can’t see the cords along the jamb. Most sash cords are rope; chains were used on larger commercial windows and sometimes in more expensively built homes. In repairs, it’s important to use true sash cord or chain as materials not made for that use will stretch and break prematurely. You can find sash cord or chain at your local hardware store, big box retailer, and online.
10 steps to repair broken sash cords
- Remove stops: Slide small pry bar along the joint and locate the securing nails. Gently pry to loosen the nails and remove the stop, being careful not to split the wood. If the windows are painted, break the paint seal along the stop and window jamb, cutting along the joint with a sharp utility knife. If stops are screwed in place, simply remove the screws and the stops will come off.
- Slide out bottom sash: Pivot the sash out. While it’s out, install weather stripping along the bottom of the rail and at the meeting rail.
- Open weight access door: Along the jamb, about 6 inches up from the sill, you’ll find a small wooden door about 12 inches long that you can remove to access the window weights in the wall cavity. If the jamb is painted, you will need to cut along the joint of the access door to allow removal. After cutting the paint seam, tap lightly on the access panel. If they are screwed at the top, use a screw driver to remove; if they’re nailed, use a slim pry bar.
- Remove the weight: Reach in and pull the window weight, a heavy metal cylinder, through the door.
- Remove the broken cord: Pry the cord from the side of the sash. Sometimes the cords are nailed. Pull the broken cord out of wall pocket.
- Fish new cord: Run the new cord over the pulley and into the wall cavity until you see the end at the access door. Pull cord out of access door.
- Tie cord to weight: Tie the cord with a knot to the top of the weight. Set the weight back in cavity and reinstall the access door.
- Tie cord to sash: Set the sash back in jamb. Pull the cord so the weight hits the pulley and then release it back down a couple of inches. Tack with a small nail through the cord at the pulley to keep the weight in that location. Tip the sash out from the top, leaving the base on the sill but exposing the cord channel in the sash. Cut the cord for length where the cord attaches to the sash, allowing for a small knot. Tie the knot and insert in the channel, fixing it in place small nail. Remove the tack nail at the pulley.
- Install the stops: Complete the project by reinstalling the stops (and weather stripping if you need it) flush against the sash but with a little room to allow operation. Before finish nailing, test the operation of the sash.
- Upper sash: If you want the upper sash to operate, do the following after Step 2. Break the paint seal on the interior and exterior of the upper sash and along the parting bead. Remove the parting bead to remove the upper sash. Follow the same procedure noted above to install new cord. Install the parting stop (or a new stop if it broke during removal) and finish Steps 3-9.
Follow these same steps to remove the sash for glass or putty replacement or more extensive wood sash repair.
This article first appeared in South Bend Tribune.
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