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 Denver typically charge $85–145/hr. Window replacement averages $300–800 per window, while entry doors run $800–2,500 installed.
Permits and inspections requirements vary by Denver. Check with your local building department before starting.
Brick, stucco, and wood siding common. Asphalt shingles perform well in dry climate. High altitude UV exposure requires quality paint and sealants. Freeze-thaw cycles cause expansion cracking.
Freeze-thaw cycles in Denver stress window seals, weatherstripping, and door frames. Check for drafts annually and replace worn weatherstripping before winter. Intense UV exposure in Denver degrades window seals, fades finishes, and warps exterior doors. Low-E glass and UV-resistant finishes extend service life significantly.
DIY in Denver: Denver's moderate licensing and outdoor-focused culture support DIY repairs. Freeze-thaw maintenance and seasonal winterization are common homeowner tasks. High altitude knowledge is helpful. Most people hire professionals for electrical and HVAC work.
- 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.
Describe the problem. Uncle AI asks the right questions and tells you exactly what's broken — and whether you should fix it yourself or call someone in Denver.
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