How to Paint Window Frames and Sills
Windows are the trickiest trim to paint. Too much paint and they stick shut forever. Too little and you get thin, uneven coverage. Learn the professional sequence and techniques that prevent stuck windows while achieving crisp, clean lines.
Quick Summary
Time needed
1-1.5 hours per window
Cost
$15-25 in supplies
Difficulty
Moderate to Hard
Why Window Painting is Tricky
Windows combine every painting challenge in one place: intricate detail work, moving parts that can't be painted shut, glass edges that show every mistake, and awkward angles that test your brush control.
The Stuck Window Problem: Paint even slightly into the channels where windows slide, or let sashes dry touching each other, and you'll have a window that's painted shut. It takes 10 seconds to ruin and hours to fix.
The good news: with the right sequence and a small brush, window painting is manageable. The key is knowing what NOT to paint and when to move the window.
Tools and Materials
Required
- •1.5-inch angled sash brush
- •Semi-gloss or satin trim paint
- •Paint tray or small container
- •Drop cloth
Recommended
- •Razor blade scraper
- •Putty knife or 5-in-1 tool
- •Painter's tape (for glass if desired)
- •Damp rag for quick cleanup
Understanding Window Parts
Knowing the terminology helps you understand the painting sequence:
Step-by-Step Guide
1. Position the Window for Access
For double-hung windows (most common), raise the lower sash and lower the upper sash so they pass each other. This gives you access to all surfaces.
Window Positioning:
- •Raise lower sash to about 6 inches from top
- •Lower upper sash to about 6 inches from bottom
- •Clean any dust or debris from exposed areas
2. Paint the Muntins First (If You Have Them)
If your window has muntins (the grids between glass panes), paint these first. Use your small sash brush and work carefully along the glass edge.
Pro Tip: Let paint overlap onto glass by 1/16 inch. This seals the wood-glass joint against moisture. You'll scrape the excess later with a razor blade.
3. Paint the Window Sashes
Paint the horizontal and vertical parts of each sash (the movable window frames). Paint the exposed portions of both sashes while they're in this position.
Critical: Do NOT paint the top or bottom edges of the sashes where they contact the jamb. Do NOT paint the sides where they slide in the channels. Paint only the visible face and the inner edge that faces into the room.
4. Reverse Window Position and Finish Sashes
Once the first position dries to touch (15-20 minutes), reverse the window position: lower the bottom sash, raise the top sash. Now paint the parts that were hidden before.
Don't return windows to fully closed position until paint is completely dry (2-4 hours) or they may stick together.
5. Paint the Window Jamb (Frame)
Paint the stationary frame pieces: the channels where windows slide (paint only the visible face, not inside the channel), the head jamb (top), and side jambs.
Don't Paint
- • Inside the sliding channels
- • Weather stripping
- • Window locks/hardware
Do Paint
- • Visible jamb faces
- • Parting beads (stops)
- • Window frame edges
6. Paint the Casing Trim
Paint the decorative trim around the window opening just like you would paint any other trim. Cut in where it meets the wall, then fill in the face.
7. Paint the Sill Last
The window sill is the horizontal shelf at the bottom. Paint it last so you don't rest your hand on wet paint while working on the upper areas. Use smooth horizontal strokes following the wood grain.
Tip: Sills take more abuse (water, sun, hand contact) so consider an extra coat here for durability.
8. Move Windows Before Paint Fully Dries
This is crucial: once paint is dry to touch (30-60 minutes), open and close each window several times. This breaks any paint seal before it fully cures. Don't skip this step.
Important: If you wait until paint is fully cured (24 hours), the window will be stuck. You must move it while paint is still slightly flexible.
Professional Tips
Use a Quality Sash Brush
A good 1.5-inch angled sash brush ($12-20) is worth every penny for window work. The narrow size gives you control in tight spaces, and quality bristles hold a sharp edge for clean lines against glass.
Razor Blade Cleanup
Wait 24 hours for paint to fully cure, then use a razor blade scraper at a 45-degree angle to remove any paint from glass. This is faster and gives cleaner results than trying to tape perfectly or cut absolutely perfect lines.
Work in Good Light
Windows are backlit, which makes it hard to see wet paint against the white trim. Use a portable work light from the side to see what you're doing. Paint windows during daytime if possible.
Frequently Asked Questions
How do I paint windows without getting them stuck shut?
The key is to avoid painting the moving parts where they contact the frame. Don't paint the channels where the window slides, and don't let paint build up where sashes meet. Once paint is dry to touch (30-60 minutes), open and close the window several times to break any paint seal before it fully cures.
Should I tape off the glass when painting windows?
It's optional. Taping takes time, and a steady hand with a quality sash brush can cut clean lines. Many professionals skip tape and use a razor blade scraper to clean up any paint on glass after it dries. If you're new to cutting in, tape the glass leaving a tiny gap (1/16 inch) so paint seals the glass-to-wood joint.
What order should I paint window parts?
Paint in this order: 1) Muntins (the grids between glass panes), 2) Window sashes (the moving parts), 3) Window jamb and frame (stationary parts), 4) Casing trim around the window, 5) Sill. This lets you blend wet edges and prevents painting yourself into corners.
Ready for the Next Step?
Windows done. Now apply the second coat to all trim for durability and perfect coverage.