What's actually causing this
Wood windows absorb humidity and swell during summer. Painted windows get sealed over time as coats of paint build up in the gap between the sash and the frame. Older double-hung windows also lose their balance springs.
What you'll need
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- Utility knife Shop →
- Putty knife or window zipper Shop →
- Sandpaper (80 grit) Shop →
- Candle wax or silicone spray Shop →
Step-by-step fix
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1
Score the painted seam
Run a utility knife along the gap between the sash and the frame — inside and outside. This cuts the paint seal without damaging the wood.
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2
Break the seal with a putty knife
Insert a wide putty knife into the seam and tap it gently with a hammer to work around the perimeter. Work slowly to avoid cracking the glass.
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3
Sand swollen edges
Open the window enough to access the edges. Sand any swollen areas with 80-grit sandpaper until the sash slides freely.
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4
Lubricate the channels
Rub candle wax or apply silicone spray to the window channels and the sash edges. Do not use oil-based lubricants — they attract dirt and degrade wood.
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5
Test and repaint if needed
Open and close the window several times. If you sanded bare wood, apply primer and paint to prevent future swelling.
Door and window contractors in New York typically charge $100–200/hr. Window replacement averages $300–800 per window, while entry doors run $800–2,500 installed.
Permits and inspections requirements vary by New York. Check with your local building department before starting.
Brownstone facades and masonry are common. Pointing and brick repair are frequent maintenance items. Window restoration in historic buildings requires specialized craftspeople. Roof access on multi-unit buildings is shared; repairs need landlord/board coordination.
Freeze-thaw cycles in New York stress window seals, weatherstripping, and door frames. Check for drafts annually and replace worn weatherstripping before winter.
DIY in New York: NYC's building code and co-op/condo board requirements make DIY repairs more restricted than most metros. Simple fixture swaps are generally fine, but anything touching plumbing lines, electrical, or structural elements typically requires licensed professionals and permits.
- The window frame is visibly bowed or twisted.
- The sill is rotted — the entire window unit may need replacement.
- A double-hung window sash falls when released (broken balance spring or spiral rod).
- The window is part of a casement and the crank mechanism is broken.
Let Uncle AI diagnose it first.
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