How to Repair Old Windows

Updated: Mar. 19, 2024

Don't replace casement windows—repair them

FH08SEP_WINNEW_01-2Family Handyman
Learn how to fix common casement window problems. Free up a sticking window, replace a broken crank operator or sagging hinge, even replace an entire sash. Repairs are simple, and a lot cheaper than replacing the whole window.

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If you’re thinking about replacing your casement windows because they’re drafty, fogged up or just hard to open, consider this: You can fix most of the problems yourself for a fraction of the cost of new windows—and it won’t take you more than an hour or two per window.

In this story, we’ll walk you through the fixes for the most common casement window problems. (Casement windows are the type that swing like doors.) You won’t need any specialty tools, and the materials are available from most window manufacturers or online window supply companies.

Although your windows may look different from the ones shown here, the techniques for removing the sash and fixing problems are similar.

Figure A: Casement Window Operation

When you turn the handle, the operator moves the crank arm and the split arm operator. The split arm operator then opens the window sash. Casement window operators come in several styles. They may look complex, but they’re easy to disconnect, remove and replace.

Fix a stripped crank handle

File the shaft

File a flat spot on the operator shaft, then insert a longer setscrew into the handle. The flat side lets the setscrew lock onto the shaft.

Window handle

Replace the original setscrew with a longer one.

If you turn your window handle and nothing happens, the gears on your handle, crank operator shaft or both are probably stripped. Take off the handle and look for signs of wear. If the teeth are worn, replace the handle (available from manufacturers, window dealers, or search online for “window replacement parts”). If the shaft is worn, you can replace the whole operator (see the next fix). But here’s a home remedy to try first.

Start by backing out the setscrew to remove the handle (some newer handles don’t have setscrews and simply pull off—and this fix won’t work). If you have a folding handle, mark where the setscrew is on the operator shaft when the window is closed and the handle is folded up. Remove the handle and file the shaft so the setscrew can lock onto the shaft (photo). The metal is tough; it’ll take about 15 minutes to get a flat side. Or use a rotary tool with a grinder bit to speed up the job. Vacuum the shavings out of the operator so they won’t harm the moving parts.

Reattach the handle with a longer setscrew (sold at hardware stores). If you open and close the window a lot, this fix may not hold up in the long run.

Replace a stubborn crank operator

Photo 1: Pop out the crank arm

Open the window until the crank arm bushing is aligned with the guide track notch. Push down on the arm to pop the bushing out of the track.

Photo 2: Pry off split arm operator

Slide back the retainer clip on the arm and pry the arm off the stud on the sash bracket with a screwdriver.

Photo 3: Remove crank operator

Lift off the casement cover to expose the crank operator. Remove the screws, take out the crank operator and replace it.

If the splines on the crank operator shaft are worn or broken off, the gears don’t turn easily or at all, then it’s time to replace the crank operator.

Don’t worry if you can’t find the make, model or serial number of the crank operator. You just need a picture. Snap a digital photo, email it to a window replacement parts company and the company will sell you a new one. Or mail the company a print photo. You can also look at online catalogs at the replacement parts companies to find an operator that matches yours.

To replace the operator, first take the crank arm off the sash. Most crank arms slip out of a notch on the guide track on the sash (Photo 1). Others are pried off with a flathead screwdriver, or a channel is unscrewed from along the bottom of the sash. If the operator also contains a split arm operator, unhook that, too (Photo 2).

Slide or pry off the operator cover. If you have a removable cover, cut along the casement cover with a utility knife to slice through any paint or stain that seals it on the window jamb. Remove the trim screws along the top of the casement cover. Gently pry the cover loose (Photo 3). Be careful—the cover can easily break! Unscrew the crank operator. Set the new operator in place, aligning it with the existing screw holes, and screw it to the jamb. If the cover isn’t removable, crank operator screws will be accessible on the exterior of the window.

Fix a sticking window

Photo 1: Disconnect the arms

Open the sash and disconnect the crank arm. Pry the split arm operator off the top and the bottom of the sash with a screwdriver (the hinge arms easily pop off).

Photo 2: Slide the hinge shoe out

Slide the hinge shoes out of the hinge channels at the top and bottom of the window to remove the sash.

Photo 3: Drill new holes

Set the hinge channel in place, slightly over from its former location. Drill new holes, then screw it to the jamb.

If you have a window that drags against the frame when you open it, close the window and examine it from the outside. The sash should fit squarely and be centered in the frame. If not, you can adjust the position of the sash by slightly moving the hinge channel. (If the window is centered and square but still drags, see the next fix.)

You can move the channel at the top or the bottom of the window, depending on where the sash is dragging (but don’t move both channels). Start by taking out the sash (Photos 1 and 2). If the hinge arm is screwed to the sash, see ‘Replace a fogged sash’ below.

Mark the hinge channel location on the frame, then unscrew the channel. Fill the screw holes with epoxy (for vinyl windows) or wood filler (for wood windows). Filling the holes keeps the screws from realigning with their old locations when you reinstall the channel. Scrape the filled holes smooth before the epoxy sets. Place the channel back on the jamb, about 1/8 in. over from the mark (move the channel away from the side of the sash that’s dragging), drill 1/8-in. pilot holes and then reinstall it (Photo 3).

Replace a sagging hinge

Fasten the new hinge

Align the new hinge arm with the screw holes and fasten it into place. If the screw holes are stripped out, fill them with toothpicks dipped in wood glue, let the glue dry, then cut the toothpicks flush.

Over time, hinge arms that support heavy windows can start to sag, causing the sash to hit the frame in the lower corner that’s opposite the hinge. First make sure the window sash is square and centered in the window opening. If it’s not, see the previous fix. To eliminate drag in a window that fits squarely, replace the hinge arms at the top and the bottom of the window. You can buy the hinges at window hardware supply stores.

Remove the sash from the window. The hinge arms are located near a corner or in the middle of the window frame. Unscrew the hinge arms from the window, then install the new ones in the same locations.

Seal a drafty window: Weather stripping casement windows

Remove weather stripping

Work the old weather strip out of the groove gently to avoid tearing it and leaving the spline stuck in the groove.

Weather stripping often becomes loose, worn or distorted when the sash drags or when the strip gets sticky and attaches itself to the frame, then pulls loose when the sash is opened. Windows have weather strip on the sash, frame or both. Regardless of its location, the steps for removing and replacing it are the same. Weather stripping is available from your window manufacturer. The window brand and glass manufacturer date are etched in the corner of the glass or in the aluminum spacer between the glass panes. You’ll also need the height and width of your sash (take these measurements yourself).

If the weather strip is in good shape and loose in only a few places, like the corners, apply a dab of polyurethane sealant (sold at hardware stores) to the groove and press the weather strip into place. Otherwise, replace the entire weather strip. First remove the sash and set it on a work surface so you can access all four sides. If the weather strip is one continuous piece, cut it apart at the corners with a utility knife.

Starting at a corner, pull the weather strip loose from the sash. If the spline tears off and remains stuck in the groove, make a hook from stiff wire to dig it out.

Work the new weather strip into the groove, starting at a corner. You’ll hear it click as the strip slides into the groove.

If the window is stuck shut, it’s likely that the weather strip is sticking. After you muscle it open, spray silicone lubricant on a rag and wipe it on the weather stripping. Don’t use oily lubricants; they attract dust.

Replace a fogged sash

Photo 1: Remove the sash

Take off the sash by removing the screws in the channel and the hinge arms. Then slide the sash off the hinge arms.

Photo 2: Attach the new sash

Align the sash lip with the hinge arms, then slide the sash onto the hinges. Insert screws to fasten the sash in place.

If you have broken glass or fogging (condensation between the glass panes), you’ll have to replace the glass or the entire sash. If the sash is in good shape (not warped or cracked), you can sometimes replace just the glass. Call your window manufacturer to see whether glass replacement is an option and if a fogged window is covered under your warranty. You’ll need the information that’s etched into the corner of the glass and the sash dimensions.

Contact a glass repair specialist to have only the glass replaced (look under “Glass Repair” in the yellow pages or search online). Or you can replace the sash yourself and save some of the cost. Order it through the manufacturer.

To replace the sash, first remove the old one. You take this sash off by removing the hinge screws (Photo 1). For sashes that slide out, see ‘Fix a sticking window’ above. Remove any hardware from the damaged sash and install it on the new sash (this sash doesn’t require any hardware).

Install the new sash by sliding it onto the hinge arms, then screw it to the hinges (Photo 2).

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Cordless drill
  • Drill bit set
  • File
  • Pry bar
  • Utility knife

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

  • Replacement window hardware
  • Silicone lubricant