There’s a common misconception that if your home has older windows that are in less-than-perfect condition, you must replace them with new windows. But as long as the window is structurally sound, you can fix most problems and extend the window’s service life by many years.
There are instances when a window is so badly damaged that it’s beyond repair, such as when the entire frame is rotted, or if there’s extensive termite damage. Then, it’s time for a new set of windows. However, some of the most common window problems can be fixed with minimal time and money.
1. Block out drafts.
Caulk around window frames to block out drafts and wind-driven rain.
The number one problem with older windows is that they don’t seal very tightly, which allows cold air to blow in during the winter and cooled air to escape during the summer.
To fix the seals, start by caulking around the exterior window frame to block the flow of air from the outside. Look for gaps between the perimeter of the frame and the house siding or exterior trim boards.
Use a stiff-bristle brush and putty knife to clean the gaps of all dust, dirt and debris. Then, overfill the gaps slightly with acrylic-latex silconized caulk. Smooth out the caulk bead with a wet finger.
Next, seal around the inside of the window with weatherstripping. Choose window weatherstripping that’s large enough to fill the gaps around the sash but still flexible enough to allow the window to operate. Install the weatherstripping along the two side jambs, the sill, and at the meeting rail where the two sash come together.
2. Repair rotted wood.
Carve away rotted wood from the sash and sill, and then apply epoxy wood filler.
The exterior frames of wood windows are susceptible to rot caused by moisture, as well as damage from birds and insects. If you don’t repair the frame in a timely manner, you’ll eventually have to replace the entire window. Fortunately, most wood rot can be fixed in a matter of minutes.
Start by using a sharp chisel to cut and carve away the rotted wood. It’s imperative that you remove all the rot and expose the solid, sound wood underneath. If you leave behind any decayed wood, the rot will continue to spread.
Next, buy two-part epoxy wood filler and mix it according to the manufacturer’s directions. Use a flexible-blade putty knife to spread the filler over the damaged section. If the repair is more than an inch deep, fill it halfway, then wait for the filler to harden. Then, apply a second coat, overfilling the area slightly.
Allow the epoxy to cure for about an hour, then sand it smooth either by hand with 80-grit sandpaper, or with an orbital finishing sander. Wipe away the sanding dust with a damp cloth, then apply a coat of primer. Finish with two applications of a topcoat of paint.
3. Unstick stubborn sash.
The sash on older double-hung and single-hung windows are notorious for becoming stuck and difficult to open. A stuck sash is far less of a problem on crank-out casement windows.
Sash typically become stuck either because the counterbalance mechanism breaks or because the sash is painted shut. It’s important to note that if you do have a stuck sash, you should resist the temptation to pound on it with a hammer or hit it with your hand. You’ll only damage the sash or hurt yourself.
The counterbalance mechanism is installed against the side jambs and attached to the sash. It’s spring-loaded and designed to offset the weight of the sash, making it easier to open and close and window. However, if the mechanism seizes up or snaps, it’ll be very difficult to budge the sash.
New counterbalances are available directly from the window manufacturer, as well as from window replacement parts companies found online. The proper way to install new counterbalances differs slightly from one window manufacturer to the next but, typically, you must remove the sash, pry out the old counterbalances, and fasten the new counterbalances to the side jambs. Then, attach the spring-loaded mechanism to the sash and reinstall the sash.
If the window is painted shut, take a sharp utility knife to slice through the paint seal along the interior stops. Then, cut through the paint along the sill and at the meeting rail where the two sash meet.
Once you’ve sliced through the paint-sealed joints, push a stiff-blade putty knife into the joints all around the perimeter of the sash. Then, try lifting the sash with two hands. Position each hand near the upper outer corners of the sash, not in the middle.
If the sash doesn’t open, don’t force it. Instead, cut through the paint seal alongside each of the interior window stops, then use a thin pry bar to carefully pry off the stops. Gently tug the sash loose. Reinstall the old stops, or cut and install new stops against the sash.
4. Refinish the exterior.
Scrape away loose, blistered paint, then prime and repaint the surfaces.
To shield wood window frames from the elements, it’s important to maintain a protective coat of paint on all exterior surfaces. Once the paint starts to crack, blister and peel, water can soak into the wood and begin to rot the window frame, sill and sash.
Use a tungsten-carbide paint scraper and wire brush to remove loose, blistered paint. Be careful not to gouge the wood. Next, lightly sand all surfaces with 100-grit sandpaper. You can use a hand-sanding block or orbital finishing sander.
As you sand, try to “feather” the existing paint coat to blend smoothly into any bare wood spots. Also, be sure to sand over the old paint coat, which will roughen the surface and help the new paint coat to adhere.
Patch any cracks, holes and depressions with two-part epoxy wood filler or auto-body filler. Overfill the patches, then sand them smooth with 80-grit sandpaper.
Wipe off all sanding dust with a damp cloth, then apply one coat of exterior-grade primer, followed by two coats of house paint.
It’s good to inspect the paint finish on your windows annually. You should pay particular attention to south-facing windows, which are exposed to the most amount of sunlight and can fade more easily.
5. Fix busted sash cords.
Before there were mechanical counterbalances, windows were fitted with a system of sash weights, pulleys and cords that offset the weight of the sash. This simple system works surprisingly well—until the sash cords break. When that happens, the weights drop down inside the wall, making it virtually impossible to open the window.
Here are the basic steps to fixing busted sash cords:
- Pry off the window stops from the side jambs and remove the bottom sash.
- Pry off the parting bead from the window frame and remove the top sash.
- Unscrew the access panel from each side jamb to expose the void inside wall.
- Fish out the sash weights and broken cords from inside the wall. Cut away the old cords.
- Thread new cords over the pulleys and tie them onto the sash weights. Drop the weights back inside the wall.
- Fasten the cords to each side of the top sash.
- Reinstall the top sash, then replace the parting bead.
- Repeat these steps to attach new cords to the weights for the bottom sash.
- Set the bottom sash into the window frame and reinstall the window stops.