How to Fix a Window Stay That No Longer Holds the Sash Open

A window stay that no longer holds the sash open is one of the most common minor window problems in NZ homes, and in most cases it's a straightforward DIY repair. The fix usually comes down to tightening a worn friction mechanism, replacing a cheap stay arm, or swapping out a broken peg-and-slot stay — all jobs a confident homeowner can tackle in under an hour with basic tools.

Understanding How Window Stays Work

Before you start, it helps to know what type of stay you have. The two most common types in NZ homes are:

• Friction (casement) stays — a hinged arm with a friction pivot or locking lever that holds the sash at any angle. Common on aluminium casement and awning windows.
• Peg-and-slot (traditional) stays — a bar with holes or slots that drop onto fixed pegs on the sill. Common on older timber sash and casement windows.

Both types can fail in different ways, so identifying yours first will save you time.

Common Causes of a Failing Window Stay

• Worn or loose friction pivot — the most frequent cause on aluminium windows. The pivot bolt has loosened over time, reducing the clamping force that holds the arm in position.
• Broken or bent stay arm — the arm itself may be cracked, corroded, or bent out of shape, especially on older or coastal properties exposed to salt air.
• Missing or worn pegs — on peg-and-slot stays, the pegs can snap off or the holes in the bar can elongate, so the bar no longer locks in place.
• Loose fixing screws — the stay may simply have pulled away from the frame or sill, causing it to swing free.
• Paint or debris build-up — layers of paint or grime can jam the mechanism or prevent the peg from seating properly.

Tools and Materials You'll Need

• Screwdrivers (flathead and Phillips)
• Spanner or adjustable wrench
• Replacement stay (if needed — available at Bunnings or Mitre 10)
• Mild abrasive or fine sandpaper (for paint build-up)
• Penetrating oil (e.g. WD-40)
• Timber plugs or longer screws (if screw holes are stripped)

Step-by-Step: Fixing a Friction Stay

1. Open the sash fully and locate the friction pivot — usually a bolt or rivet at the elbow of the stay arm.
2. Tighten the pivot bolt using a spanner or screwdriver. Turn clockwise in small increments, then test whether the arm holds position. Don't overtighten or the stay will be too stiff to operate.
3. Check the fixing screws at both the frame bracket and the sill bracket. If screws spin without gripping, the holes may be stripped. Fill with a timber plug or use slightly longer, wider screws for a fresh bite.
4. Test the stay at several positions. If it still drops, the friction washer inside the pivot may be worn beyond adjustment — in this case, replacement is the best option.

Step-by-Step: Fixing a Peg-and-Slot Stay

1. Inspect the pegs on the sill plate. If a peg is snapped, unscrew the sill plate and take it to a hardware store to find a matching replacement plate.
2. Check the bar holes — if they've elongated, the bar needs replacing. Bring the old bar to match the length and hole spacing.
3. Clear any paint build-up from the pegs and bar holes using fine sandpaper or a craft knife. Apply a small amount of penetrating oil and wipe clean.
4. Refit and test — the bar should drop firmly onto the pegs and resist the weight of the sash without lifting off.

Replacing the Stay Entirely

If repair isn't practical, replacing the stay is usually inexpensive and straightforward. When buying a replacement:

Aluminium window hardware is widely stocked at Bunnings, Mitre 10, and PlaceMakers. Take the old stay with you to match it up.

NZ Building Code and Ventilation Considerations

If your window stay is on a habitable room window, keep in mind that Clause G4 (Ventilation) — confirm the exact clause reference with MBIE Building Performance or your local council — of the NZ Building Code requires adequate openable ventilation area. A stay that prevents the window from opening properly could affect compliance — worth bearing in mind if you're replacing stays in a rental property, where Healthy Homes Standards also set minimum ventilation requirements.

For windows above ground level, also consider fall prevention. If the window is in a child's bedroom or above a drop of more than 1 metre, the stay may need to limit opening to no more than 100 mm (unless the window is above a balustrade). Check MBIE Building Performance guidance or ask your local council if you're unsure.

Safety Note

Always prop the sash securely before working on a stay — a falling sash can cause serious injury or break the glass. Never lean out of an open window while making repairs at height.

When to Call a Professional

Most window stay repairs are well within DIY reach. However, call a qualified glazier or joiner if:

• The window frame itself is damaged, rotten, or out of square — a failing stay can sometimes be a symptom of a bigger structural issue.
• The sash is warped or swollen and no longer sits correctly in the frame.
• You need to replace glazing as part of the repair (cutting and fitting glass is best left to a professional).
• The window is part of a heritage or character home with non-standard hardware that's hard to source.

You can find qualified local glaziers and window specialists on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance — NZ Building Code
• Tenancy Services — Healthy Homes Standards
• BRANZ — Build Magazine and homeowner resources
• Bunnings — Window hardware
• Mitre 10 — Window stays and fittings
• WorkSafe NZ — Working safely at height