How to Seal Your Campervan Windows: A Practical Guide

Sealing campervan windows properly is one of the most important steps in your conversion project. If you don’t seal your windows right, you risk leaks, mold growth, and even damage to your campervan’s structure. But with the right products and techniques, you’ll keep moisture out and enjoy a cozy, dry home on wheels—no matter the weather.

Why Sealing Campervan Windows Matters

Your campervan faces rain, snow, humidity, and temperature changes every day. Without an effective seal, water can sneak between your window sizes and dimensions frame and the vehicle body, causing:

Persistent leaks
Mold and mildew growth
Rust and structural damage

Sealing creates a waterproof barrier, protecting your investment and making your campervan more comfortable and durable.

Best Campervan Window Sealing Materials & Brands

Here’s a quick look at popular sealing options, including trusted brands like Dometic, Seitz, and Polyvision.

Seal Type	Examples / Brands	Benefits	Trade-offs	Best For
Butyl Tape	Polyvision Butyl Tape	Great initial adhesion, easy to apply	UV exposure can degrade over time	Temporary seals, quick fixes
Polyurethane Adhesive	Sikaflex, 3M, Dometic	Strong, flexible bond; long-lasting	Requires good prep & curing time	Permanent, structural seals
Silicone Sealant	Dow Corning, Seitz	UV resistant, flexible, waterproof	Weaker adhesion than polyurethane	Secondary seals, weatherproofing
Compression Seals / Gaskets	Seitz Campervan Windows	Reusable, clean installation	May not seal perfectly against leaks	Windows designed for gasket fit

Polyurethane Adhesive: The Gold Standard for Campervan Windows

If you want a permanent, durable seal that can handle vehicle vibrations and temperature swings, polyurethane adhesive (like Sikaflex or Dometic’s PU adhesives) is your best bet.

Why Choose Polyurethane Adhesive?

Strong, elastic bond: It flexes with your campervan’s movement, preventing cracks.
Long-lasting: Properly applied, it lasts for years without failing.
Weatherproof: Resists water, UV, and temperature extremes.

What You Need to Know:

Application: Apply a continuous bead around the window frame, typically in a triangular or hourglass shape. This shape balances adhesion area and flexibility.
Surface Prep: Clean, degrease, and lightly sand the surfaces to ensure the adhesive sticks well. Dirt or oil will cause failure.
Curing: Polyurethane cures with moisture in the air, taking anywhere from 24 hours for handling strength to 7 days for full cure. Plan your schedule accordingly.
Costs: Expect to pay around $10-20 for a tube of high-quality PU adhesive, enough for 1-2 windows.

Butyl Tape: Quick and Easy—But Watch the Trade-Offs

If you’re on a budget or need a fast solution, butyl tape (like Polyvision Butyl Tape) is a popular choice.

Pro: Sticks immediately, waterproof, easy to work with.
Con: Degrades under prolonged UV exposure, so it’s best for temporary seals or areas protected from direct sunlight.
Cost: Very affordable, usually under $10 per roll.

Silicone Sealants: Great for Extras, Not Primary Seals

Silicone is flexible and UV resistant, making it perfect for sealing small gaps or as a secondary seal. However, it doesn’t bond as strongly as polyurethane.

Use silicone for: sealing trim, roof vents, or window edges after the main seal is in place.
Avoid silicone for: structural window bonds where strength is critical.

Surface Preparation: Don’t Skip This Step!

No matter which sealant you choose, prepping your surfaces is non-negotiable:

Clean thoroughly: Remove dust, grease, and rust.
Abrade (sand) surfaces lightly: This improves adhesion.
Prime if recommended: Some adhesives work better with primer.

Skipping prep can cause leaks and shorten your seal’s lifespan.

Quick Decision Guide: Choose the Right Seal for Your Campervan Windows

Scenario	Recommended Seal Type	Why
Permanent, strong window installation	Polyurethane adhesive (e.g., Sikaflex, Dometic)	Durable, flexible, long-lasting
Temporary or budget-friendly	Butyl tape (e.g., Polyvision)	Easy to use, immediate adhesion
Secondary sealing & weatherproofing	Silicone sealant (e.g., Seitz)	UV resistant, flexible but weaker bond
Campervan windows designed with gaskets	Compression seals/gaskets (e.g., Seitz)	Clean install, reusable

Final Tips for Sealing Your Campervan Windows

Take your time: Rushing leads to mistakes.
Follow product instructions: Different adhesives have different curing times.
Check your work: After curing, inspect your seals for gaps or bubbles.
Plan for maintenance: Even the best seals need periodic checks.

By choosing the right campervan window sealing method for your needs and following these practical tips, you’ll keep your van dry, comfortable, and ready for adventure.