How to Seal RV Windows: The Ultimate Guide

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An RV window that isn’t properly sealed can wreak havoc on your vehicle.

The good news is that sealing your windows is an easy process that doesn’t require fancy tools or extensive knowledge of carpentry.

All you need are some basic supplies and our step-by-step instructions below. Plus, we’ll show you how to extend the life of your new seals for many years to come.

How to Reseal RV Windows Step-by-Step

How To Reseal & Replace RV Windows

Important: This tutorial is for the popular clamp-ring style windows found on many RVs. If your vehicle has a different style of window, you may need to contact the manufacturer for resealing instructions.

Materials Needed:

Tip: In the video above, they recommend the Seal-Tite Foamcore Window Kit. That is a quality kit, but if you’re just resealing one or two windows, it may be cheaper to buy the materials we list above or price out your own at a local store.

Step 1: Remove the Clamp Ring

First, we need to remove the screws on the interior of the RV window frame, which allows us to manually remove the clamp ring that helps hold the window in place.

Tip: Inspect the outer edge of the window and remove or loosen any caulk to help the window removal process go a lot smoother.

Step 2: Remove the Window

Now it’s time to remove the window! This process is much easier and reduces the risk of broken window glass if you have a helping hand.

With one person inside the RV and one standing outside, work together to remove the window. The person inside the RV will gently push the window outwards, removing any old caulk still holding the window in place, while the second person gently holds and guides the window.

Step 3: Remove Old Sealant

Once the RV window is removed, place it on a clean surface (outside part of window face down) and use a putty knife to remove the old sealant from the window trim. Inspect and remove any old sealant on your RV as well.

Step 4: Clean the Window

Clean the window and exterior of the RV with cleaning alcohol and a clean cloth. Make sure no dirt, dust, or debris could potentially obstruct the new RV window sealant and prevent it from forming a proper seal.

Tip: Be careful not to remove any of the paint or graphics from your RV when removing the old sealant.

Step 5: Apply New Sealant

Starting at the bottom of the RV window where the weep holes are located, begin installing the butyl sealant tape.

Work your way around the window frame, applying the replacement seal tape roughly 1/8 inch in from the window’s edge.

After working around the window with the sealant, overlap 3/8 of an inch where the putty tape meets at the bottom.

Inspect the entire length of the sealant and ensure there are no gaps between the sealant tape and the window frame. This will help ensure an air and water-tight seal.

Step 6: Re-Install the RV Window

Again, with two people, one inside the RV and one outside, gently lift the window into place.

Important: Be sure the window is right-side up when re-installing it. The weep holes should be at the bottom.

With the person standing outside the RV still holding the window in place, the person inside can start screwing the window back in.

For the tightest seal, screw on the clamp ring in this order:

  1. Start by screwing in the upper left screw, then move onto the lower right, lower left, and then screw in the upper right corner of your clamp ring.
  2. After screwing in the corners, you can finish screwing in the rest of the screws.

Step 7: Complete the Process

Your window should now be installed and have a tight seal around the frame.

But there’s one more quick step to complete. Apply the Dynaflex 230 Premium Elastomeric Sealant to the top of the outside window frame using a caulking gun. Make sure to apply the sealant until you hit the end of the corner radius. Smooth the sealer with your finger and allow it to completely dry before washing or driving your vehicle.

That’s it! Your RV window is now tightly sealed!

Important: If you don’t feel comfortable resealing an RV window, take your vehicle to a certified RV specialist to replace the window seals.

How to Extend the Life of Your RV Window Seals

Extending the life of your RV window seals is easy with a little routine maintenance and the right products.

Use Quality Sealant

The best first step to prolong the life of your seals is to use a high-quality, durable sealant when replacing your existing seal.

The seal under your window frame should be a butyl rubber sealant designed for vehicle use.

Waterproof Butyl Tape Sealant

Waterproof Butyl Tape Sealant

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The sealant bead you run across the top of the window frame should be either Dicor sealant or Dynaflex RV Flexible Sealant. Never use silicone caulk sealant around your RV windows.

Keep Your Windows Clean

When debris and dirt build up on an RV window seal, it can lead to the seal’s deterioration. Keeping your RV clean will not only improve the look of the vehicle but will also prolong the lifespan of certain components (i.e., your window seals). Wash your RV regularly and ensure all dirt or debris around the windows is removed.

Protect the Seal

When possible, park your motorhome in the shade to avoid exposing it to direct sunlight. When winterizing your camper, your best bet is to store it in a temperature-controlled storage unit. That’s not always possible, so at the very least, keep your vehicle covered and out of the elements when not in use.

When your RV has been exposed to extremely high temperatures, keep your windows closed and untouched until the temperature has stabilized to avoid unneeded stress on the seals.

There are also protectants available that can be applied directly to the window seals as a preventative measure. These products will help prolong the seal’s life by preventing shrinking and cracking.

While the seal under the window frame may not be reachable, you can apply 303 protectant spray to the sealant at the top of the window and the seals and gaskets around the window edge.

303 Marine & Recreation Aerospace Protectant

303 Marine & Recreation Aerospace Protectant

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RV Window Seal FAQs

What Is the Best Sealant for RV Windows?

The best sealant for RV windows is butyl sealant tape. Butyl rubber tape is perfect for sealing high-shock areas, like the windows in a mobile home (that travel down bumpy roads).

This super-strong and waterproof sealant helps to reduce the noise and wind when driving your recreational vehicle at high speeds.

Waterproof Butyl Tape Sealant

Waterproof Butyl Tape Sealant

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We also recommend you use an elastomeric sealant around the top of the window to further protect it from rain, snow, and other elements. You’ll want a high-quality sealant with flexible properties to withstand the joint movement involved when traveling. 

Dynaflex 230 Premium Elastomeric Sealant

Dynaflex 230 Premium Elastomeric Sealant

Buy Now on Amazon

Clicking this link to make a purchase may earn us a commission at no additional cost to you.

How Often Should RV Windows Be Resealed?

How often you need to reseal your windows will just depend on how much wear and tear your seals have seen, the amount of exposure to the sun and other elements, the quality of the sealant used, and many other factors.

I’ve seen older mobile homes (30+ years old) still with their original seals. And I’ve had to replace a seal on a window in a vehicle less than 10 years old.

It’s recommended to be proactive and check the outside window seals regularly by making it a part of your camper de-winterization process. If you notice your RV window seals shrinking, you have leaking windows, or you are replacing an RV window, you will need to reseal the window.

Should You Caulk Around RV Windows?

If your window is properly sealed with butyl tape sealant, you should only need to caulk the top of the window, making sure you caulk until the end of the corner radius. This will further prevent any water leaks.

Tip: Do NOT use a silicone caulking sealant around your RV windows. Use either Dicor or Dynaflex RV Flexible Sealant.

What Size Butyl Tape Should I Use for RV Windows?

A 5/16″ to 3/8″ thick butyl sealant tape will suffice for most RV window applications. When in doubt, check the size of your existing seal.

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