Window Won't Stay Up? Single- and Double-Hung Balance Repair
A single- or double-hung window that won't stay up, slams down or is very hard to lift has a worn, broken or mismatched balance, the spring system in the side of the frame that carries the sash's weight. The fix is to identify the balance type and replace it with an exact match, which is a repair, not a reason to replace the window.
The balance is the spring hidden in the side jamb that holds the sash at any height; when it fails the sash drops, creeps or becomes hard to lift.
Four main types: channel (block-and-tackle), constant-force coil, spiral tube, and box-style overhead balances.
Replacements must match closely; even 1/32 inch off can make a difference.
Constant-force coil balances are common in vinyl windows; block-and-tackle balances are found on wood, fibreglass and composite windows and have more parts to wear.
A falling sash can crush fingers and break glass, so keep the window shut and locked until it is fixed.
Older wood windows with original sash cords and weights can often be restored, and Toronto's Heritage Grant program favours repairing original windows on designated properties.
On this page
When a single- or double-hung window won't stay open, slides down on its own or slams shut, the balance has failed. The balance is the spring system hidden in the side of the frame that carries the sash's weight so it stays wherever you leave it. When the spring weakens, breaks or comes loose, gravity wins.
The good news is that balances are replaceable parts. A window with a failed balance usually has years of life left once the right balance is fitted, so this is a repair job rather than a reason to replace the window.
First, make it safe
A heavy sash that drops without warning can crush fingers and break glass. Until it is fixed:
- Keep the sash fully closed and locked, or, if you need airflow, wedge a cut length of wood in the side track to hold it open.
- Warn children and anyone else in the house not to lift it.
- If the sash has come loose from the frame at one side, don't try to force it back. Tilted or hanging sashes are heavy and the glass is easily cracked.
The four types of window balance
Modern windows use four main balance families, plus an outdated rod style you'll occasionally still meet. Pop the sash (on tilt-in windows) or look at the side jamb above the lower sash to see which you have.
| Type | What it looks like | Where you'll find it | Notes |
|---|---|---|---|
| Channel (block-and-tackle) | A long metal or vinyl channel in the jamb, containing a spring and pulleys, with a cord at the bottom | Wood, fibreglass and composite windows | More moving parts that can wear, rust or break |
| Constant-force coil | A flat stainless steel coil spring, like a tape measure, set in a pocket at the top of the jamb, with the tape attached to the sash | Common in vinyl windows | Simple and consistent over the sash's travel |
| Spiral | A tube with a twisted rod inside, attached to a shoe at the bottom | Varies by maker; common sizes 3/8 in (Series 900) and 5/8 in (Series 600) | Wound tension; needs a tension tool to install |
| Box-style overhead | A box at the top of the frame with a tape running down to the sash | Certain brands only | Brand-specific parts |
Very old wood windows may use a fifth system: cords running over pulleys to weights hidden in a cavity beside the frame. That is a different repair (new cord or chain), and those windows are often worth restoring. More on that below.
How to tell which balance you need
Getting the size right is the whole job. Look for a stamped code on the balance itself; for channel balances, weighing the sash helps pick the right spring. Even 1/32 inch off can make a difference.
Collect this before ordering:
- Type (from the table above).
- Any stamped code on the channel, tube or coil housing, and the window brand if you can find it on the frame or spacer.
- Length of the channel or tube, measured exactly.
- Sash weight for channel balances. A bathroom scale works if you can safely remove the sash.
- Shoe or pivot style at the bottom, which connects the balance to the sash.
The classic symptoms tell you which way it is off: a window that is hard to close has balances that are too strong, and one that slams down has balances that are too weak or broken.
Symptom, cause, fix
| What you notice | Likely cause | Fix |
|---|---|---|
| Sash won't stay up at all, drops fast | Broken spring, snapped cord or tape, or shoe disconnected from sash | Reconnect shoe if loose; otherwise replace balance(s) |
| Sash creeps down slowly | Weak or worn spring, or balance undersized for a heavier sash | Replace balances with correct rating |
| Sash is very hard to push down, springs back up | Balance too strong for the sash | Replace with correct rating |
| Sash tilts or racks, one side lower | One balance failed or mismatched pair | Replace both sides |
| Sash is stiff all the way, but stays where left | Dirty or painted tracks, swollen wood, worn weatherstripping | Clean and lubricate tracks; free painted sash; check seals |
| Grinding or clicking in the jamb | Damaged pulley or spring in channel balance | Replace balance |
Not every stiff window is a balance problem. Dirt in the tracks and worn pads cause many "stuck window" complaints. Clean the tracks and apply a silicone lubricant every six months. Also check the weatherstripping: felt strips need replacing every one to two years and tubular rubber or vinyl lasts about five.
Replacing the balance: what's involved
The general sequence on a tilt-in window:
- Raise the sash a few inches and release the tilt latches at the top.
- Tilt the sash in and lift one side out of the jamb, then the other. Support its full weight; it is heavier than it looks.
- Lock the balance shoes in place (usually with a flat screwdriver) so they don't fly up the jamb.
- Remove the old balances: unscrew channel balances at the top; unhook coil tapes; lower and release spiral shoes.
- Install the new balances, set tension if required, re-seat the sash pivots in the shoes, and test through the full travel.
Two warnings. Spiral balances and coil springs store energy and can spin or snap back if released carelessly, so eye protection is sensible. And on upper floors, a tilted sash is a real drop risk; this is where a two-person crew and a proper grip matter.
What it costs
There is little published pricing specific to balances in the GTA. The closest guide is the general window-hardware range: about $150–$450 for bent frames or broken window hardware on a scheduled visit, or $350–$650 as an emergency. What moves the price:
- balance type and whether it is a stock size
- both sides versus one (we recommend both)
- number of windows in one visit
- access: second-floor sashes and condo units take longer
Older Toronto homes: sash weights and heritage windows
Toronto has a lot of older housing stock: 29% of the city's dwellings were built in 1960 or earlier. Where original wood hung windows survive, a sash that won't stay up can be as simple as a broken cord.
If the house is designated under the Ontario Heritage Act, the City's Heritage Grant program covers the repair of existing, original windows and doors, and its guidance says original windows that are sound or repairable must be retained and restored. Repairing the balance system fits that approach. For permits and heritage districts in general, see our guide to permits for glass and window work in Toronto.
Rentals and bedrooms
In Toronto rentals, windows must be kept in good repair and free from defects and missing components under the property standards by-law. A sash that won't stay open is a defect, and fixing it is normally the landlord's job; see our rental broken window guide.
In bedrooms, a hung window that can't be held open may not serve as a practical emergency exit. The Ontario Building Code expects bedroom egress windows to open without tools and provide at least 0.35 m² of clear opening. Treat a failed balance in a bedroom as a priority.
When to call a pro
- You can't find a code or brand and aren't sure which balance to buy.
- The window is on an upper floor, or the sash is large and heavy.
- It's a spiral balance and you don't have a tension tool.
- The sash is cracked or fogged as well, so the glass and the hardware can be done in one visit.
- You have several windows of the same age going at once.
If the sash or frame itself is rotted, split or warped, a new balance won't hold it true. That's a window-replacement job, not a repair, and we'll tell you if that's where you are.
For casement windows with cranks rather than sliding sashes, see our casement crank guide.
Next step
A window that won't stay up needs the right balance, fitted and tensioned correctly. See our window hardware repair service or send us a photo of the jamb and any stamped codes for a free quote. If the glass is cracked or fogged too, we can replace the pane or sealed unit in the same visit and keep your frame.