June 24, 2024

How To Reseal RV Windows Like a PRO

Leaky roofs and leaking windows are the top two causes for costly water damage in RVs. You can prevent this from happening though by being proactive and making leak prevention a priority. I’ll explain how to identify potential areas of concern and seal them properly before they become a problem.

Extend the life of your RV and avoid costly repairs by performing regular inspections and maintenance to keep water outside where it belongs. It is an easy and inexpensive task for any Do-It-Yourself RV owner. Here’s what you need to know. 

How often should you inspect RV seals?

Inspect the seals and check for water damage before purchasing any RV, even new ones. If you find poor seals, it could signal a potential water intrusion problem. 

Once you are confident that the RV is properly sealed, then I’d recommend rechecking them at least once a year. It’s best to do this in the summer so you have time to fix any seals before fall and winter. 

If you cover the RV in the off-season, a good cleaning, inspection and resealing is a great thing to do beforehand. You’ll be all ready to go when you remove the cover in the spring. 

What to look for?

Check Exterior Openings

Inspect exterior windows, doors, compartment openings, exterior lights, sidewall seams and other openings in your sidewall. Look for cracks, gaps, or poor application of sealant. 

Old Cracked Windows Seals - Windows Like a Pro - RVWITHTITO.com
This window seal will let water get in

Pay special attention to seams on the top and sides. They are more susceptible to wear and leakage since they get the majority of water runoff from the roof. 

TIP: Look for rusted screws. Rusty screws that secure wall panels, lights, and other openings are a sign that moisture is behind the outer wall.

Finally, Locate problem areas where water runoff from your roof occurs. Pay extra attention to those spots. If your not sure where those are, look for streaking along the sides. One areas often missed is next to the awning.

Here’s a little tip to keep water from running down the side of your RV

Check Interior Walls

Moving inside, water damage around windows can cause swelling, discoloration or possibly mold in the surrounding wall paneling. Perform a visual inspection then press the surface around the window checking for softness. 

Areas around the bottom of the window often are the first to show signs of water damage. Water leaking from the top of a window often runs down the side of the window into the paneling around the lower corners.

How to repair bad seals?

Once you’ve identified what areas need to be resealed, follow these steps to get a professional result.

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STEP 1 – Remove the old sealant

Use the pointy and flat end of a scraper to remove all existing sealant. Remove as much old sealant as possible. Mineral spirits can help loosen up residual sealant after the first scrape. Pour some on a rag wipe the around the area giving it a few minutes to do its magic before continuing.

Seal Windows Like a Pro - RVWITHTITO.com
Use a scraper to remove old sealant

If you’re worried about scratching your paint job, then I’d suggest using a plastic scraper. You may need to cut away sealant stuck in the cracks. A utility knife works well for this. 

STEP 2 – Clean and dry the surface to be resealed

This step is critical to getting a proper seal. Spray on some window cleaner and use a clean rag or shop towel to clean the area. The window cleaner will clean it up nicely and evaporate quicker. 

Seal Windows Like a Pro - RVWITHTITO.com
Clean surface very well before applying new sealant

Dry the entire area with a towel before moving on. 

STEP 3 – Outline the area to be resealed with painters tape

This step is critical to getting that professional result with a sharp edge. It will be time consuming as opposed to just free handing it. Trust me, the extra effort will be worth it. Leave a small gap of around 1/8 inch between the window frame and tape for sealant.

Seal Windows Like a Pro - RVWITHTITO.com
Tape around window frame leaving 1/8″ border for sealant

STEP 4 – Apply the sealant

What kind of sealant to use? Everybody has their favorite sealant for each type of surface and application. You’re RV manufacturer may also recommend one. I prefer the clear 100% silicone sealant from my local store because it works great and comes in a squeeze tube.

Seal Windows Like a Pro - RVWITHTITO.com
I prefer a clear silicon in a squeeze tube because it’s easier to apply in small areas

Clear GeoCell ProFlex works good too and is a bit more expensive. I do keep a couple of tubes of ProFlex handy but primarily use it in other areas. Don’t be afraid to experiment with other sealants and find your favorite.

PRO TIP: Do not seal the bottom edge of the window. Leaving a gap on the bottom edge unsealed gives water that gets in a way to drain out. Otherwise, it’s trapped in there soaking into your walls.

When applying the sealant, take your time and squeeze a thin bead of sealant into the crack around the top and sides of the window. Then run your finger along the edge to smooth it out. Overlap the sealant slightly over the tape. When you pull the tape off, it will leave a nice sharp line.

STEP 5 – Remove the tape

Wait a few minutes for the sealant to set up a bit, but not too long. Then carefully remove the blue tape. Apply a dab of mineral spirits to a shop towel and lightly wipe off any smudges.

STEP 6 – Let it dry

Watching it dry won’t make it dry faster, but do take time to stand back and admire your great work! Then walk away and let it set for about 24 hours.

More things you can do to prevent water damage

Cover your RV when not in use

Keeping your RV covered is the best way to protect it from rain, snow, leaves, pollen as well as the sun. A covered parking spot is ideal (I sure wish I had one), but using an RV cover is the next best thing. In fact, I used an RV cover to protect our Class C for many winters.

There are lots of RV covers like these available on Amazon for your length and type of RV. Find one that has protects from rain as well as sun. I’ve learned that covers with thicker fabric last longer.

Handing a large RV cover can be really challenging. So here are some helpful tips to make handling a large cover easier.

Keep your RV exterior clean

Washing your RV regularly helps prevent moss and mildew from forming in window cracks. Also, don’t ignore the roof. Clean it too. Remember that any nastiness on the roof will just run down onto the sides when it rains.

Cover Roof Seams with roof repair tape for long-term protection

The seams on your RV roof are the most exposed to weather. Adding an extra layer of protection on top of any existing lap sealant creates an extra layer of protection. Doing this can really extend the life of your existing seals. Four inch wide Eternabond or Gorilla Water Sealing tape works good for this.


Regular inspections and preventative maintenance is the best way to prevent water damage in RVs. When you notice an issue, deal with it sooner than later. 

A good seal job should last at least a couple years, maybe longer with just a little touch-up. After purchasing our older class A motorhome, I spent a couple weeks resealing the entire RV. That way I know I’ve got a good starting point. 

I hope this helps you out instead of just giving you more work to do. Here are a couple related articles that may interest you as well.

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