Window Reseal

Leaking cabin windows are one of the most common issues on the Catalina 27. The original sealant hardens and cracks over time, allowing water to run down the cabin liner and into places you'd rather it didn't go. The good news is that resealing the windows is a straightforward weekend project. This guide is based on the window reseal procedure shared in the IC27A file library (opens in new tab).

When to Reseal

• Water staining on the cabin liner below or beside windows.
• Visible cracking, separation, or hardening of the sealant around the window frame.
• Condensation or fogging between the window and frame that doesn't clear.
• Preventively — if the windows have never been resealed and the boat is 20+ years old, it's time.

Materials

• Butyl tape (1/8" × 3/4" or similar) — preferred for its long-term flexibility and easy future removal.
• Alternatively: Dow 795 silicone or 3M 4200 (not 5200 — you'll want to be able to remove the windows again someday).
• Plastic putty knives or scrapers.
• Denatured alcohol or acetone for cleaning.
• Painter's tape for masking.
• New stainless screws if the originals are corroded.

Procedure

1. Remove the interior trim ring or frame screws from inside the cabin. The windows on most C27s are held in place by a frame that screws through the cabin side from inside. Take photos before disassembly so you remember the order.
2. Carefully push or pry the window out from inside. A helper outside to catch it is useful. The acrylic is brittle — don't force it.
3. Remove all old sealant from both the window and the cabin opening. A plastic scraper avoids scratching the acrylic. For stubborn sealant on the fiberglass, a heat gun on low can help soften it.
4. Clean all surfaces with denatured alcohol. Let dry completely.
5. Inspect the window for crazing, cracks, or deep scratches. If the acrylic is badly crazed, consider replacing it — a local plastics shop can cut new pieces from your old window as a template.
6. Apply butyl tape around the window opening on the cabin side, creating a continuous bead with no gaps. Overlap the ends slightly.
7. Press the window into position from outside. Have your helper inside start the screws to hold it in place.
8. Tighten screws evenly in a star pattern — snug, not gorilla-tight. The butyl should squeeze out slightly all around, confirming a complete seal.
9. Trim excess butyl with a plastic putty knife. Clean up any residue with mineral spirits.

Tips from the Community

• Do one window at a time so you always have a reference for reassembly.
• Number the screws and their positions — hole spacing can vary slightly between windows.
• Butyl tape is strongly preferred over liquid sealants. It never fully cures, stays flexible for decades, and makes future removal easy.
• If you use a liquid sealant, mask both sides with painter's tape for clean lines.
• Check the drain channels in the window frame — some models have weep holes that can clog with old sealant.

While you have the windows out, it's a good time to inspect the surrounding deck core for moisture damage. Tap the area around each window opening and check for soft spots. See Critical Inspections for more on deck core assessment.