How To Install A Campervan Roof Vent Fan

After living full-time in my campervan for the last few years I can say with certainty that my campervan roof vent is one of the best installations I included in my DIY build. A roof vent is one of the first things most people install, so the learning curve seems daunting – but I promise you it’s actually MUCH easier than it appears.

The process of installing your fan is simple: pick a fan, decide where it’s going to go (this part is actually the hardest in my opinion), cut the hole, sit the fan in and connect a few things.

Truly, getting the placement right is 70% of the work. There’s a few things you want to consider before you start cutting holes in your van, so lets get into it!

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Step 1: Choose A Fan

Choosing the best fan for van life comes down to a few things: what’s your budget? what features do you need? how much space do you have on the roof?

The two top contenders in the marketplace are MaxxFans and Fantastic Fans. Personally, I’ve never met anyone who loves their Fantastic Fan, but I know many people (myself included) who rave about the MaxxFan Deluxe. I’ve had my MaxxFan Deluxe since 2020 and it’s been one of the best investments I built into my van. (Campervan HQ typically has the best price)

Consider these questions when picking your fan:

• Dimensions. Most fans require a 14×14 inch hole, but if you have less space there are smaller options (like the MaxxFan Dome or models which use an 11×11 inch hole)
• Roof layout. Most fans take up a larger footprint on the roof than just the 14×14 inch opening, so consider this when determining where you’ll fit other roof items, like solar panels.
• Electrical requirements. Most campervan roof vents require a simple 12v connection, which just means running one set of positive & negative wires to the unit.

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Step 2: Choose An Installation Location

There’s many things to consider when picking a spot. You want to spend a good amount of time on this decision because a cut hole cannot be uncut.

• A mostly flat spot is best for installation. On most vans, this means closer to the middle of the roof.
• How will you maximize airflow? For example, you want to increase space between your open windows and vent location so more air is circulated throughout the entire vehicle. A fan directly above your only open window won’t move much air outside of that immediate spot.
• Roof layout. How does your campervan roof vent fit in relation to all the other items you plan to install on your roof? This can include things like solar panels, AC units, awnings and roof decks.
• Drillable locations. Most vans come with a BEMM (Body and Equipment Mounting Manual), it’s typically a free download you can find with a quick Google search for your year, make and model. Within it are instructions for how to modify the vehicle, including where you can safely drill. NEVER drill through a cross beam in the roof. These are structural support and crucial incase your vehicle ever rolls. While it limits your options, you absolutely want to place your roof installations between these crossbeams.
• Intended use. Where your roof vent fan goes is also influenced by how you plan to use it. Most of my open windows are in the front of my van, so I placed my fan in the back to optimize airflow. This is also convenient for me because it’s directly above my bed – and nighttime is when I use the fan the most. If you plan to cook a lot then it might make sense to consider installing your fan over the cooking area to help quickly vent odors and oils.

Step 3: Mark And Cut The Hole

This step will likely be the most time consuming step in the entire process. Not the actual cutting, but the marking. Like they say, measure twice and cut once.

Mark Your Cut

The difficult with marking your hole location is that vans are not square or level. Making sure that the hole you’ve marked inside matches the hole you’ve marked outside (on the roof) can be tricky. When I installed my roof vent I used the crossbeams (sometimes called ribs) as my “anchor” – meaning I could see the rib on the inside of the van and the rivets for it on the roof of the van, so I measured back from the rib to get my markings to be aligned with each other inside and outside.

Use A Small Pilot Hole To Confirm Measurements

Cut a tiny pilot hole in the middle of your marked space. This step is crucial. At this point your interior and exterior markings are probably almost perfectly aligned, but they may be off by an inch or two. The pilot hole in the center will allow you to measure your dimensions from a specific point and make any adjustments necessary. Once you have interior and exterior markings aligned you can double check that this spot is still right for your needs and vent dimensions.

Prep Your Space

I highly recommend placing painters tape over the metal of your van to protect it from the jigsaw, which can scratch the paint. Painters tape removes easily without residue, which is why I think this is better than another type of tape, like duct tape.

It’s also extremely important to limit the number of metal shavings from cutting which will fall into the van. These can float around the van for years and cut through the paint which then allows rust to form. I taped a large garbage bag to the roof under my cutting location to collect the shavings, but a big tarp would also work.

Cut Your Hole

Cutting the hole is actually the easiest part. Start by using metal drill bits to cut into the 4 corners of your hole – these will allow you to insert your jigsaw blade and to turn the corners more easily.

It’s important to use the right blade in your jigsaw as well as the right speed settings for sheet metal. Using the right tools will make this job so much easier – it’s like cutting butter!

Before you move onto the next step you want to dry fit your campervan roof vent to make sure your opening will work.

Most campervan roof vents also have several screws that are installed along the top flange. Dry fit the top flange onto the roof and mark and drill where each of these screws fit through the plastic cover.

File And Paint The Exposed Metal

Unpainted metal on a van are bad news – they’re exposed which can fast track them to rust. For every hole you make in your van you want to file it with a metal file so it’s smooth, and then cover it with Rust-Oleam paint. Don’t worry about making this look pretty, it’s going to be covered anyway.

Step 4: Install Your Campervan Roof Vent and Waterproof

Congratulations! The hardest part of this install is done.

Some manufacturers instructions will have specific requirements for installing and waterproofing. If that’s the case, follow those. Otherwise, I’ve found butyl tape and Sikaflex to be a perfect waterproofing combination!

Each material will have its own specific instructions for prepping the surface for the adhesive, but in general a generous amount of rubbing alcohol to remove any dirt and residue from the surfaces is a good idea.

Butyl tape is double sided and very sticky. This is a common method for waterproofing roof-mounted things on RVs or vans. Be careful because once you put this down you’ll never get it off again.

Tape the bottom of the fan so all 4 sides are completely covered with no open gaps at the corners. Then lower the fan into the roof on your hole so the butyl tape makes a watertight seal between the fan and the roof.

Next, screw the flange into place in the pre-designated mounting points along the outer flange.

Finally, you want to use Sikaflex to cover all the screw heads as well as the entire perimeter of the flange to prevent water from entering. You cannot use too much Sikaflex! I promise you, this is a ‘more is better’ situation.

Step 5: Connect The Interior Parts And Hook Up To Electrical

This final step is quick and painless. From here you can add the interior parts of the campervan roof vent to the roof-mounted parts you’ve just installed.

You’ll need to connect the vent to your electrical system. Typically these fans do not require much power so you can get away with smaller wire but ALWAYS double check you have the right gauge for the job. I also strongly recommend installing quick-disconnects in case you ever need to replace or troubleshoot your roof vent in the future.

Lastly, most of these roof vents come with an interior flange that’s deep enough for an RV. This is deeper than most vans will need, so you can take an exacto knife and cut down the flange depth to the correct measurements for your DIY install. A jigsaw or bandsaw will also work well.