5 Years Later: The Maxx Fan Rust Check (And Why Your DIY Install is Fine)
Hey everybody, Matt here for AVC and welcome back to AVC Chronicles!
Today, we're doing a different kind of video—a little bit of an experiment. We have a van that was built here in 2020, which means its Maxxfan install is now five years old. We’re swapping it out for a CloudCap, and I thought it would be the perfect opportunity to pull this fan out and see how the original install held up against five years of Colorado sun, snow, ice, and everything in between.
The big question we always get is about rust when using self-drilling screws. The good news? I think what we found will give every DIY builder a lot of confidence.
Let's see what's up on the roof!
Step 1: The Sealant Check (Maintenance is Key!)
Before we even touched the fan, the roof was pressure-washed (though some stubborn debris remained—a good reminder to check your roof a couple of times a year!).
Once the fan was pulled, the first thing we saw was the Dicor lap sealant.
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Finding: The 5-year-old lap seal had started to crack and separate.
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Takeaway: This is totally normal, but it's why you need to check your seals at least once a year (ideally before and after winter). You don't want these cracks with snow and ice buildup, which can force water in.
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Maintenance Tip: If we were just doing upkeep, you could clean the old seal with a scouring pad and lay a new bead of lap sealant right over the top to reseal it.
Step 2: The Rust Myth (Self-Drilling Screws Win)
The most common fear we hear is that self-drilling screws puncture the metal and instantly invite rust, shortening the life of your van.
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The Test: We removed all the self-drilling screws and inspected the metal roof and the screws themselves.
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Finding: After five years, there was no surface rust on the screws or in the metal holes. The holes, the inner primed edge we cut for the fan, and even the raw metal edges looked totally fine.
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Takeaway: A proper install using self-drilling screws combined with quality sealant (like butyl tape and lap sealant) does an excellent job of sealing out moisture. Don't let the fear of rust stop you from using these easy, effective fasteners.
Step 3: The Glue Factor (Why Adhesives Rule)
Once all the screws were removed, we tried to lift the Maxxfan flange out.
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The Test: Can we easily remove the fan once the mechanical fasteners are gone?
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Finding: Absolutely not. Even without a single screw, the flange was glued down tight! We had to pry and scrape to get it off.
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Takeaway: The butyl (or "bud") tape that sits between the fan flange and the roof is incredibly effective. After five years, it was still plenty pliable and extremely sticky. This is your primary moisture barrier, and it's holding that fan down tight. You don't need to worry about the fan flying off or leaking if you use a quality sealant like butyl tape.
Conclusion: Your Install is Solid
After a thorough inspection, the 5-year-old Maxxfan install looked great.
The winning formula remains: Butyl tape + Dicor lap sealant + self-drilling screws. This combination creates a bomb-proof, sealed install that lasts years, even under tough weather conditions. It just needs a little maintenance on the sealant every now and then.
If you’re taking on your own vent fan install, we hope this gives you the confidence to trust the process.
Thanks for reading, and we’ll see you on the next one!