Window Won’t Stay Up? Diagnose and Fix Sash Balances

A sash that slides back down the moment you let go is more than an annoyance. It can pinch fingers, slam onto the sill and crack glass, and it leaves you propping the window open with a book or a stick. When your window won’t stay up, the cause is almost always the balance system hidden in the side jambs, the springs or cords that counter the weight of the sash. In many cases the fix takes under half an hour and costs nothing, because a pivot shoe has simply popped out of its track or a spiral balance has lost tension.

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Start by figuring out what kind of balance your window uses. Once you know that, you can try the quick fixes first (re-seating, re-tensioning, cleaning) and only move to replacement if a part is actually worn out or broken. Most double hung and single hung windows built in the last 50 years use one of four systems, and each fails in its own predictable way.

Why a Window Won’t Stay Up: The Usual Suspects

Every movable sash is heavy. A typical vinyl or wood lower sash weighs 10 to 25 pounds, and larger units with insulated glass can weigh more. The balance system holds that weight in check so the sash stays wherever you leave it. If the window won’t stay up, one of these things has happened:

• A pivot shoe or balance shoe has come loose from the sash pin, so the spring is no longer connected to the sash.
• A spiral balance has unwound and lost the tension it needs to support the sash weight.
• A cord or string has snapped inside a block-and-tackle balance or an old sash cord system.
• A spring is fatigued after years of cycles and simply cannot carry the load anymore.
• The balance is the wrong size for the sash, often after a previous repair used whatever part was on hand.

Less often, the problem is friction rather than weak support. Paint, dirt or a warped jamb can make a sash stick halfway and then drop suddenly. Clean and inspect the tracks before you buy parts.

Identify Your Balance Type

Raise the lower sash fully and look at the side jambs. On many modern windows you can tilt the sash inward by pulling the tilt latches at the top corners, which exposes the balance channel. Here is what to look for.

Spiral Balance

A spiral balance is a narrow tube, usually about 5/8 inch in diameter, mounted inside the jamb channel. Inside the tube is a twisted metal rod and a spring. The bottom end has a small mounting clip or a cam that attaches to the sash. These are common on vinyl replacement windows. They are often color coded at the end to indicate the weight they are rated for.

Block-and-Tackle Balance

This type uses a metal or plastic channel with a coil spring at one end and a set of pulleys with a cord at the other. The cord connects to a pivot shoe that rides in the jamb track. Block-and-tackle balances show up in many vinyl and aluminum windows and are usually stamped with a code that identifies length and weight rating.

Constant Force Coil Spring

A flat ribbon of steel coiled like a tape measure sits in a pocket near the top of the jamb, with the ribbon running down to a shoe attached to the sash. These are found on many tilt-in vinyl and wood windows. The spring pulls with roughly the same force at any height.

Sash Cord and Weight

Older wood windows, especially those built before the 1950s, use cotton or nylon cord running over a pulley at the top of the jamb to a cast iron weight hidden in a pocket behind the trim. When the cord breaks, the sash drops and the weight falls to the bottom of the pocket. You often hear a thud inside the wall when this happens.

Tools and Materials

• Flathead and Phillips screwdrivers
• A spiral balance tension tool or a small slotted tool for unhooking spirals
• Needle-nose pliers and a putty knife
• Locking pliers or a clamp to hold a balance shoe in place
• Silicone spray lubricant (not oil, which collects dust)
• Work gloves and safety glasses
• Painter’s tape and a soft surface such as a folded moving blanket to rest the sash on
• Replacement balances or a window sash balance replacement kit, if needed

Glass Handling Safety Before You Start

Any repair that involves tilting or removing a sash means you are holding a heavy pane of glass. Wear gloves and safety glasses the whole time. Large sashes are a two-person carry, with one person on each side gripping the frame rather than the glass. Never flex the sash or let the corners strike the floor, a sill or a table edge, because glass is most vulnerable at its edges and corners. Lay the sash flat on a padded surface, not leaning against a wall where it can slide and fall. If the glass is already cracked, tape across the crack in an X pattern before handling. Older windows may have annealed (non-tempered) glass that breaks into sharp shards, while doors and some large windows use tempered glass that crumbles. Treat both with care.

Quick Fixes to Try First

These steps solve a large share of cases where a double hung window won’t stay up, and they require no new parts.

1. Check the pivot shoes. Tilt the sash in and look at the shoes in the jamb tracks. Each shoe should sit at the same height on both sides with its cam or slot facing the sash pins. If one shoe has ridden up the track or turned sideways, the sash pin is no longer engaged.
2. Re-seat a loose shoe. Use a flathead screwdriver to rotate the shoe’s cam so the slot faces up (unlocked position). Slide the shoe down to match the other side. Lower the sash so the pins drop into both shoes, then tilt the sash upright. Rotating it back to vertical locks the cam onto the pin.
3. Reconnect a spiral balance. If the spiral rod has slipped off the sash clip, hook it back on and give it the tension it needs (see the next section).
4. Clean and lubricate the tracks. Vacuum the jamb channels, wipe out grime and spray a light coat of silicone lubricant. A sash that drags can feel like it lacks support when it is really fighting friction.
5. Look for paint or debris. Run a putty knife along the stops and parting beads. Dried paint can cause a sash to stick and then release suddenly.

Adjusting Spiral Balance Tension

When a window is not staying up and it uses spiral balances, lost tension is the prime suspect. You can usually restore it in minutes.

1. Tilt the sash in and remove it, setting it on your padded surface.
2. Insert the tension tool into the bottom of the spiral rod. Hold firmly, because the spring will try to spin.
3. Pull the rod down about 3 to 4 inches and unhook it from the mounting clip.
4. Turn the tool clockwise to add tension. A common starting point is 3 to 5 full turns for a lower sash, though larger sashes need more.
5. Rehook the rod into the clip and repeat on the other side with the same number of turns.
6. Reinstall the sash and test. If it creeps down, add one or two turns per side. If it shoots up, remove a turn.

Always keep the turns equal on both sides, or the sash will rack and bind in the frame.

Replacing a Worn Balance

If the spring is fatigued, a cord is broken or the coil ribbon is kinked, replacement is the real fix. A window sash balance replacement kit or individual balances matched to your window solve the problem for years.

Match the Part

Remove the old balance and read any stamped codes on the channel or tube. Measure the length of the balance and note the diameter or width. For spirals, note the color of the end bushing. Bring the old part to a supplier if you can. A balance that is too weak will let the sash drop, and one that is too strong will make the window spring open.

Block-and-Tackle Replacement Steps

1. Tilt in and remove the sash.
2. Lock the pivot shoe with a screwdriver and lower it to the bottom of the track so the spring relaxes.
3. Unscrew the top of the balance channel from the jamb, then disengage the shoe and lift the balance out.
4. Insert the new balance, screw the top in place and attach the cord hook to the new shoe.
5. Set the shoes at matching heights, reinstall the sash and test.

Sash Cord Windows

For old cord-and-weight windows, remove the interior stop molding, lift out the lower sash, open the weight pocket access panel and tie on new cord. Use a sash cord rated for the purpose; braided cotton or a polyester blend lasts longer than the cheap twine sometimes used. Pre-1978 homes may have lead paint on trim and stops, so test before scraping or sanding and use lead-safe practices.

Troubleshooting After the Repair

• Sash still drifts down: add tension or confirm the balance weight rating matches the sash. Heavier triple-pane glass needs stronger balances.
• Sash won’t stay open but only on one side: one shoe or balance is not engaged. Check both pins.
• Sash pops up too quickly: the balance is too strong or overtensioned. Back off a turn on spirals.
• Window binds or racks: unequal tension side to side, or a shoe set higher than its partner.
• Grinding noise: a cracked shoe or a damaged pulley. Replace the shoe.

Cost Ranges

Doing it yourself is inexpensive. Spiral balances and block-and-tackle balances generally run in the low tens of dollars per pair, and pivot shoes cost a few dollars each. A tension tool is a small one-time purchase. Sash cord for a historic window is cheap per foot. Hiring a window repair technician usually costs somewhere between about $100 and $300 per window depending on access and parts, and full window replacement runs much higher, so it pays to rule out a simple balance fix before you consider a new unit.

When to Call a Pro

Call a window repair specialist if the sash is too heavy or large to handle safely, if the glass is cracked or the seal has failed, or if you cannot identify the balance type or find a matching part. Second-story windows that require working from a ladder outside are also better left to a pro. Historic wood windows with rotted sills or jambs may need carpentry beyond a balance swap. And if you have several windows that won’t stay open, a technician can often service them all in one visit for less than you might expect.