How to Reseal a Fixed Window: A DIY Guide to Eliminating Drafts
Take a walk around your house today. Find a window that whistles in the wind or shows a crack in the caulk. With this guide, you now have the confidence to fix it permanently. A properly resealed fixed window isn't just a repair—it's an investment in comfort and efficiency.
Below is the step-by-step process to reseal the window frame yourself. Tools You’ll Need High-quality silicone or polymer-based caulk. Caulk Gun: For a steady, even bead. Removal Tools: Utility knife or a specialized sealant remover. Cleaning Supplies:
Special Cases
- Glazing putty (traditional wood frames): soften old putty with heat/have removed; apply fresh linseed oil–based putty or modern compatible substitutes; press glass and tool putty; allow full cure before painting.
- Metal frames (aluminum/vinyl): use compatible neutral-cure silicone or hybrid sealant; avoid acid-cure silicones on metal with coatings.
- Historic windows: match original materials and profiles; consult preservation guidance.
Before starting, gather these essentials to ensure a professional-grade seal:
For Exterior Resealing (Waterproofing the fix):
- The best sealant: 100% silicone or OSI Quad (advanced elastomeric polymer). Do not use latex outside.
- Backer rod (closed-cell foam rope, diameter 1/4” to 1/2” larger than gap)
- Caulking gun with smooth rod (not ratcheting)
- Mineral spirits or denatured alcohol (for cleaning)
- Painter’s tape (blue)
- Gloves and safety glasses
- Wood filler (if fixing rot)
- Putty knife and 5-in-1 tool
- Apply a continuous bead of neutral-cure silicone (not acetoxy—acetoxy smells like vinegar and can corrode metal frames).
- Tool the bead with a wet finger (dip in mineral spirits) or a plastic spoon for a concave profile.
How to Fix a Foggy Double-Pane Fixed Window
This is the hardest scenario. If you have condensation between the two panes of glass, you cannot “reseal” it from the outside. The inert gas (argon/krypton) has escaped, and the desiccant inside the spacer is saturated.
1. Tools & Materials Needed
- Putty knife / 5-in-1 tool
- Utility knife
- Heat gun or hair dryer (optional, for stubborn sealant)
- Caulk gun
- Painter’s tape
- Rubbing alcohol or mineral spirits
- Clean rags
- Sealant options:
