Tips for Re-sealing an RV Roof

One of the first things we realized after we bought BOBB-e is that we needed to re-seal the roof. Someone had clearly done it a few times before, but it also appeared pretty cracked and hadn’t be re-sealed for a while.

Before re-sealing

We knew we had a big task on our hands since the RV is 30′ long! We needed to do this before we hit the road, because it was going to take multiple coats of sealant, and each coat needed a full day to dry.

Step 1: What Sealant to Buy?

For many RVers, this choice is usually made for you if the roof is made of rubber. From everything we’ve seen and read on the internet, there’s a whole lot of things that you need to be aware of when replacing / repairing one. Luckily for us, our roof was made of aluminum, so we had a bit of flexibility on what we could choose. Another deciding factor for us was the fact that it had already been resealed before. We ended up going with a pretty versatile sealant called “Kool-Seal“, which is technically a 2-part sealant with a gray base coat and a white top coat. The base coat sticks to more surfaces a little better, and makes for a better layer for the top coat to stick to. Since the top coat is white, it also helps reflect a lot of the sun’s UV rays and thereby heat! So not only were we fixing cracks where water could get in, but we were also helping keep the RV cooler during the hot summer months.

Another thing we realized we needed was tape to go over the seams and provide an extra layer of protection. We went with two different kinds of tape. The first pass through we used Liquid Rubber Seam Tape (pictured below). The reason for using this tape is because the rubber sticks well to the existing surface, and the top side contains a piece of fabric to ensure that the new coats going on really soak in and seal everything.

We ended up having to replace one of the vent fans after re-sealing everything, and since the rubber tape requires a top coat of sealant to go over it, we had to find another solution. For this we went with EternaBond Tape (pictured below). The nice thing about the EternaBond Tape is that the top layer is made of a UV protective material, so no top coat is needed. If I had the whole roof to re-seal all over again, I may even consider using this over the rubber tape because of the simplicity of application. The felt layer on the rubber take really took a lot of sealant to get covered fully.

Step 2: Remove Previous Sealant

Here’s where I’ll be honest with you: this step is nowhere near as easy as it sounds. This is one of those times you’ll hear someone say something in a YouTube video along the likes of “and now all you have to do is scrape the old stuff off”. Here’s a taste of what that really looks like:

Timelapse of me scraping the roof in the hot sun

One of the reasons why this step is SOOOO difficult is because if you’re doing it in the middle of summer or anytime the sun is out really, it’s HOT! The white coating really works, but that means all the sun’s rays get reflected back at you while you’re up there. You really have to be careful about making sure you have proper eye wear otherwise you could see similar issues like you do with snow blindness after a day of having the sun reflected in your eyes.

Another one of the reasons why this is so difficult is because the previous coats are really stuck on there. In some places it was flaking / chipping off, but in others, the coating was on there like concrete. We spent days trying to get it all off, and eventually we settled on getting the majority of the flaky pieces off and then used acetone to clean the surface to prepare it for the new sealant.

Kyra chipping away at the previous layers while I take pictures

Step 3: Apply Seam Tape

This step was a lot more straightforward. The biggest issue here was trying to lay down single continuous pieces of tape 10-15ft long covering the larger seams. Some of the smaller details and pieces were tedious to get the tape around, but persistence paid off and we got everything all taped up and ready for the first base coat!

Step 4: Apply Lap Sealant Around Problem Areas

We had a few places that didn’t really accept seam tape very well, and had big enough cracks that we went ahead and used lap sealants to help us get the job done. There’s two kinds of sealants to look out for:

  • Dicor Self-Leveling Lap Sealant – this is used on places where the roof is flat. The sealant is thin enough that gravity will pull the sealant all the way down into the cracks and crevices to make sure it has a tight seal.
  • Dicor Non-leveling Non-sag Lap Sealant – this is used on vertical areas like antennas or seams between panels on the side of the RV. This is a much thicker sealant that stays where it is applied, so it does require a little bit of elbow grease to really get in some of the vertical cracks. Fair warning too, this stuff is STIIIIICKY and stringy, so make sure to cut a small bead size and have plenty of towels on hand to wipe up the mess.

Step 5: Apply the Base Coats

The biggest things to be aware of before you start applying the base coat are: 1) make sure to have enough on hand to do a full coat and 2) make sure it’s not going to rain for at least a few hours (I think it says 4-6 on the can), but ideally a full 24 hours free of rain is best. You’re also not supposed to walk on it after applying the base coat for 24 hours as well. So basically: be ready to do your work and have something else lined up to do to let it dry. We ended up doing 2 coats of base coat just to be safe (using only one can). One thing we learned is that some rollers worked best at really getting in the cracks and crevices, but then would wear out faster than the others, so I can’t really give a good recommendation either way one which rollers are best. I can say that using a roller vs. a brush was much quicker, especially on the large sections. A big brush was helpful in the smaller, harder to maneuver around areas.

Step 6: Apply the Top Coat

The top coats went on a little easier than the base coat, especially since the base coat really helped give a more even surface to stick to. There wasn’t much to this step besides making sure to apply enough and give it enough time in between coatings to dry. We lucked out that we had a few days of uninterrupted sun in a row, so we were able to knock it all out at once.

Step 7: Sit Back and Relax

That’s it, you’ve got yourself a whole new re-sealed roof, and you saved yourself a ton of money doing it yourself. I can see why so many companies charge a lot of money for this: it takes a lot of hard, manual labor to get it done. But the results speak for themselves, and the fact that you did it yourself means you have a better idea than anybody where problem spots might be in the future and you’re already prepared with the right materials to fix any potential leaks or problems that arise later on.

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