Reseal Those Windows!

{mosimage} Replacing window sealant isn’t difficult. It is time consuming, and can be a bit messy, but your average do-it-yourselfer shouldn’t have much trouble keeping the elements in their place.

Out With the Old
First you’ll need to remove the window. Most RV windows have a piece of rubber trim that hides the mounting screws. Usually it completely encircles the frame, and the ends of the trim meet each other. Carefully pry up on one of the ends and pull the trim out from the track. If you spend a lot of time in hot, high-UV country, you may find that you won’t be able to reuse your trim. Take it with you to your RV dealer and see if replacement stock is available. On one of our older rigs, replacement rubber trim just wasn’t an option, so you’ll see the mounting screws, out there “in front of God and everybody.”

Once the screws (or nuts) are exposed, use the appropriate removal bit in your battery-powered power drill. Trying to remove these characters by hand is just too time consuming. Go easy so as not to strip them. With all screws removed, from the inside you’ll need to carefully look the window over. Often the window is also secured at a few points along the inside edge, going through the side edges of the window frame into the wall section. They’re often “stapled” into place, and a very small screwdriver may assist in removing them. You can try and have a helper shove the window out from inside the coach, but often times you’ll first need to carefully work a putty knife around all the edges of the window, “cutting loose” the window from the outside wall of the rig. Give a careful but firm shove, and you’ll soon find out if you got all the staples or other hardware loose.

On metal-sided RVs, the metal panels may try and pull loose from the sidewall of the RV. Gently disengage the metal siding from the window sealant and ease it back into place.

Cleanup Work
{mosimage}Probably the most involved and time-consuming part of the process is cleaning up the old sealant. You’ll want to take a putty knife after the RV sidewall to carefully scrape away all vestiges of the old sealant material. Use care so as to not scratch the sidewall.

Removing the sealant from the window unit requires plenty of time and patience. We’ve found sitting down to the task with your favorite beverage and a friend makes the job easier. A multipurpose painter’s tool (ours is a “Husky 6-in-1”) is really helpful getting down into crevices and around corners.

It’ll take awhile to get all the old sealing material off. OK, maybe you don’t need to get “every last vestige” of the old material off, but by far you want to have as much as possible off to ensure the new sealant sticks well.

Sealant Secrets
The material you’ll use to make a new seal is called “putty tape.” There are basically two breeds of putty tape around, the “regular” stuff and butyl putty tape. For windows, we highly recommend the butyl. It lasts longer, weathers better, and just makes a whole lot better seal. Yes, it is a bit more expensive, but in the long run, you’re probably better off using it. When you buy it from the RV dealership, make sure you get the little squares of paper that go between rolls. Putty tape sticks to itself something fierce, and trying to pry rolls apart is a bear.

One note for future safety: If you have any leftover butyl putty tape when you’re done with the job, clearly mark it. We use an indelible marking pen to write “BUTYL” on the inside of the roll core. Why all this folderol? Because later, if we go to reseal a roof vent, we ONLY USE butyl putty tape in some circumstances. Butyl putty tape is the ONLY safe putty tape to use on a rubber (EPDM) roof. Regular putty tape damages this roof membrane.

If you’re working in warm weather, it’s a good thing to stick your putty tape in the freezer for a few minutes. That’s because as the tape gets warm, it becomes more difficult to separate it from its backing paper. Chilled out, the tape goes on easier, and the backing paper zips right off.

With window in hand (or on a bench), pull back a few inches of the putty tape from the roll. Don’t take the backing paper off yet, as you’ll want to firmly press the putty tape down along the inside window flange. After making a complete circuit around the flange, cut off or tear the putty tape so that the butt ends slightly overlap. Now go back and using your fingers, massage the putty tape firmly into the flange.

If you’re installing the window into a rig with metal siding, many RV professionals recommend using a double layer of putty tape. To do this, peel back the putty tape backing, and starting in a slightly different location along the flange, stick down a second layer of putty tape, just as you did the first one. Don’t peel the backing paper off until you’re ready to install the window.

Reinstalling the Window
Have an assistant ready inside to lend a hand lining up the window. Peel the backing free from the putty tape at this point. Press the window into place, and have your helper assure proper alignment. With the helper keeping the window in place, set a couple of screws to keep the window in place. Now work your way back and forth across the window, installing screws. We find using new hardware for this job is never a bad idea.

After you’ve firmed down the screws, you’ll likely have extra putty tape sticking up around the margins of the window flange. Using a putty knife, carefully cut away and remove the excess putty tape. Some RVers like to add another layer of caution on the job in the form of a small bead of sealant around the entire perimeter of the window unit. We recommend clear acrylic caulk, and curse the use of silicone-based caulk. The latter is hard to remove in the future, and almost nothing will stick to it.

If you have new trim molding to cover the screws, or if you were fortunate enough to be able to salvage the old, go ahead and slide it into place.

One down, and how many to go? It’s not an easy job, but definitely worth the trouble.


Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics. They also provide great resources in their book, Camp Hosting USA—Your Guide to State Park Volunteering. Visit for more information. 

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